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Research progress on habitat suitability assessment of cropdiseases and pests by multi-source remote sensing information
, Available online  , doi: 10.12357/cjea.20220930
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Effects of combined application of nitrogen and organic fertilizer on soil bulk density, pH and carbon and nitrogen metabolism in ratooning rice field
, Available online  , doi: 10.12357/cjea.20220886
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Difference of Effects of Non-Crop Habitat Types on the Distribution of carabid beetles and spiders in Adjacent Farmland
, Available online  , doi: 10.12357/cjea.20220963
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Aquatic product trade has implications for land use, carbon emissions and biodiversity
, Available online  , doi: 10.12357/cjea.20230009
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Effects of long-term cotton straw return and application of manure on soil nutrients and enzyme activity in cotton field
GUO Zhenwei, LI Yongshan, WANG Hui, CHEN Mengni, FAN Qiaolan, YANG Na, XI Jilong, ZHANG Jiancheng
, Available online  , doi: 10.12357/cjea.20220614
Abstract(6) HTML (2) PDF(1)
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Incorporation of straw and manure application in soil play important roles in nutrient management, maintenance of crop productivity, and improvement of soil quality. The experiment was conducted to clarify the effects of long-term cotton straw returning and manure application on soil nutrients and enzyme activities in continuous cropping cotton fields, and provide scientific evidence for cotton straw returning and manure application. This study relied on a long-term experiment (since 2007) on an agricultural management system conducted by the Niujiawa Cotton Agroecosystem Experimental Station of the Cotton Research Institute, Shanxi Academy of Agricultural Sciences. Four treatments, namely nitrogen and phosphorus fertilizer+straw stubble removal (NP), nitrogen and phosphorus fertilizer+straw returning (NPS), nitrogen and phosphorus fertilizer+organic fertilizer (NPM) and nitrogen and phosphorus fertilizer+straw returning+organic fertilizer (NPSM), were set up. The results showed that the cotton yield treated with NPS, NPM and NPSM significantly increased by 10.23%, 11.10% and 26.22% (P<0.05), compared with NP treatment, respectively. The contents of soil total nitrogen, total phosphorus, alkali hydrolyzable nitrogen, available potassium and available phosphorus in NPSM treatment significantly increased by 48.76%-60.18%, 91.23%-112.18%, 140.63%-229.17%, 35.86%-60.54% and 146.92%-483.34% (P<0.05), compared with NP treatment, respectively. NPSM treatment significantly increased soil enzyme activities, (P<0.05), soil urease activity significantly increased by 118.50%-151.84%; phosphatase activity by 76.81%-93.11%; catalase activity by 30.53%-41.33%; and invertase activity by 83.41%-129.32%, compared with NP treatment, respectively There were significant positive correlationship between soil nutrient content and soil enzyme activity. Therefore, long-term straw returning with manure application can significantly increase the cotton yield, increase the nutrient content and improve the enzyme activity for soil fertility improvement in continuous cropping cotton field
Review of relationships between soil aggregates, microorganisms and soil organic matter in salt-affected soil
DONG Xinliang, WANG Jintao, TIAN Liu, LOU Boyuan, ZHANG Xuejia, LIU Tong, LIU Xiaojing, SUN Hongyong
, Available online  , doi: 10.12357/cjea.20220752
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Soil organic matter is a fundamental aspect of cultivated land quality, which not only promotes the formation of soil aggregates but also provides nutrients for plants and microorganisms. The formation and decomposition of soil organic matter are inseparable from the participation of microorganisms. Soil aggregates not only provide a habitat for microorganisms but also provide physical protection for organic matter. In soils with high salt content, the accumulation and decomposition of organic matter become more complex. Therefore, this paper summarized soil salinization and its deleterious effects, analyzed the impact of soil salt on soil aggregate structure and microbial characteristics, and described the characteristics and accumulation rules of organic matter in saline-alkali soil. Additionally, the research progress on the impact of soil salt on soil organic matter was summarized to reveal the potential mechanism of carbon sequestration in salt-affected soils. Previous studies have shown that the organic matter content in salt-affected soil is low, the aggregate structure is poor, and the microbial activity is low. Poor soil structure leads to the exposure of soil organic matter and facilitates greater decomposition, and the low amount of exogenous organic matter input leads to difficulty in the accumulation of soil organic matter. It can be seen that salt-affected soil is a potential carbon pool, and appropriate measures can significantly increase the organic matter content of salt-affected soil. On this basis, future research directions for organic matter accumulation in salt-affected soil were proposed: 1) the response of soil aggregate structure and soil microorganisms in the process of organic matter partitioning under different salt environments; 2) the response of soil aggregate structure and soil microorganisms in the process of organic matter accumulation under the addition of exogenous organic materials; and 3) the productivity characteristics of salt-affected soil after the increase in soil organic matter. The above research clarifies the turnover mechanism of organic matter in saline-alkali soil, provides a theoretical basis for “carbon sequestration” of saline-alkali land, and provides targeted measures to improve the quality of saline-alkali farmland and promotes the green sustainable development of saline-alkali land.
Discussion on the agricultural efficient utilization of saline-alkali land resources
LIU Xiaojing, GUO Kai, FENG Xiaohui, SUN Hongyong
, Available online  , doi: 10.12357/cjea.20220967
Abstract(17) HTML (6) PDF(1)
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Currently, there are about 9.9×107 hm2 of salt-affected soils in China, in which the modern saline soil is about 3.7×107 hm2. As an important reserved cropland resources, the comprehensive utilization of saline-alkali soils play very important role for ensuring national food security. After decades of research and practice, China has formed complete technical systems in the improvement of saline-alkali land, in which the hydraulic engineering measures combined with salt leaching by fresh water irrigation and drainage systems have played a key role in the reclamation of saline-alkali soils. However, due to the shortage of water resources and climatic conditions, most of the saline-alkali land in China has not been developed and utilized. In recent years, with the development of social economy and the progress of science and technology, people have gradually realized that saline-alkali land is an integral part of the natural ecosystem, in which the saline resources including saline soils, saline water and salt-tolerant organisms etc. have played important roles in diversified food production, ecological conservation and human life. In order to promote the high-quality development of agriculture in saline-alkali areas, it is necessary to strengthen the studies on the theories and technologies of efficient utilization of saline resources and to develop the relevant industry of saline-alkali land resources utilization. This paper analyzed current situation and the problems existing in the reclamation of saline-alkali soils, and discussed the utilization of halophytes and saline water resources, the efficient improvement of salt-affected soils by fertile root zone construction, the production of high-quality agricultural products in saline-alkali soils, the space utilization of saline lands by developing facility agriculture, and the development of grass and animal husbandry in saline-alkali land. This paper will provide reference for the efficient utilization of saline-alkali land resources.
Effects of returning gramineous green manure to cotton field on soil carbon and nitrogen in saline alkali soil
WANG Jingkuan, GAO Fengshu, ZHANG Kaiyue, LI Shuai, LIU Xinwei
, Available online  , doi: 10.12357/cjea.20220221
Abstract(126) HTML (91) PDF(26)
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To explore the effect of gramineous green manure on soil carbon and nitrogen contents in saline alkali cotton fields, two low-temperature- and saline alkali-tolerant gramineous green manures, ryegrass ‘Dongmu 70’ and barley ‘Zhudamai No.4’ were selected for in situ returning experiments from 2018 to 2019. Three treatments were set up: winter fallow farmland-cotton (T1), ryegrass-cotton (T2), and barley-cotton (T3). The contents of soil organic carbon (SOC), soil total nitrogen (TN), soil microbial biomass carbon (SMBC), and soil microbial biomass nitrogen (SMBN) were measured in different treatments at different periods (15, 50, 110, and 180 d) after returning green manure to field. The soil microbial quotient (SMQ) and ratio of soil microbial biomass carbon to nitrogen (SMBC/SMBN) were calculated. The results showed that both T2 and T3 significantly increased the contents of SOC and TN, and reached maximum values of 9.50 g∙kg−1 and 798.84 mg∙kg−1 (T2) and 9.91g∙kg−1 and 759.34 mg∙kg−1 (T3) at 180 d after returning green manure, respectively, and they were significantly higher than those of T1 treatment by 29.60% and 27.85% (T2) and 35.20% and 25.13% (T3), respectively. The variation dynamics of SMBC and SMBN contents in T2 and T3 were basically similar throughout the returning period, indicating a trend of stable growth in the early stage and significantly higher contents than those in T1, and a decrease in the latter stage and slightly lower contents than those in T1 at 110 d. The maximum values of SMBC and SMBN were 217.84 mg∙kg−1 and 34.51 mg∙kg−1 for T2, and 212.88 mg∙kg−1 and 33.43 mg∙kg−1 for T3 at 50 d and were higher than T1 by 81.46% and 47.76%, and 77.33% and 43.13%, respectively. In addition, the contents of SMBC and SMBN at different periods after returning to the field demonstrated that T2 was higher than T3. The change trend in SMQ in different treatments was consistent with that of SMBC. The two green manure treatments showed higher SMQ except for 110 d. T2 reached a maximum value of 2.82% at 15 d, while T3 reached a maximum value of 2.98% at 50 d. The SMBC/SMBN values of each treatment varied from 4 to 7; therefore, the microbial community in the soil was concluded to be mainly bacteria after returning the green manure to the field. T2 and T3 showed higher SMBC/SMBN values compared with T1, except at 110 d. In conclusion, the planting and return to the field of gramineous green manure in winter fallow farmland in saline alkali soil can significantly improve soil carbon and nitrogen contents in cotton fields, ameliorate the composition of soil microbial communities, improve the effect of soil microbial carbon sequestration, and provide nutrients for the growth of subsequent crops. The research results have guiding significance for the rational utilization of winter fallow farmlands in saline-alkali soils.
Exogenous hydrogen sulfide modulates metabolic responses of sugar and phenolic acid in naked oat leaves under saline-alkali stress
LIU Jianxin, LIU Ruirui, LIU Xiuli, JIA Haiyan, BU Ting, LI Na
, Available online  , doi: 10.12357/cjea.20220649
Abstract(23) HTML (8) PDF(0)
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In order to clarify the regulatory effect of hydrogen sulfide signaling on the plant metabolome under saline-alkali stress and to reveal its mechanism of enhancing plant saline-alkali tolerance, a pot experiment was conducted with naked oat (Avena nude) as the material. Four treatments were applied to potted naked oat plants in a 2 × 2 factorial combination, including 0 or 3.00 g·kg−1 saline-alkali (molar ratio of NaCl∶Na2SO4∶Na2CO3∶NaHCO3 at 12∶8∶1∶9) added to the potting soil and spraying with distilled water or 50 µmol·L−1 sodium hydrosulfide (a hydrogen sulfide donor) on leaves at the heading stage. The effects of exogenous hydrogen sulfide on glycolytic metabolite levels, redox balance, and phenolic acid content in leaves and on the yield traits of naked oats under the four treatments were investigated using ultra-performance liquid chromatography-tandem mass spectrometry technology combined with orthogonal partial least squares discriminant analysis. Under non-saline-alkali conditions, sodium hydrosulfide application did not have a significant effect on the ratios of (reduced glutathione)/(oxidized glutathione) and (reduced coenzyme Ⅱ)/(oxidized coenzyme Ⅱ), adenosine triphosphate content in leaves, and yield traits of naked oats; however, the levels of citrate, succinate, and 6-phosphogluconolactone were significantly upregulated and those of glucose-6-phosphate, pyruvate, lactate, α-ketoglutaric acid, glutamate, asparagine, erythrose-4-phosphate, and sedoheptulose-7-phosphate were significantly downregulated in the leaves. Saline-alkali stress significantly reduced the levels of glucose, glucose-6-phosphate, fructose-6-phosphate, fructose-1,6-diphosphate, 3-phosphate glyceraldehydes, 3-phosphoglyceric acid, pyruvate, lactate, α-ketoglutaric acid, glutamate, glutamine, asparagine, erythrose-4-phosphate, sedoheptulose-7-phosphate, ribose-5-phosphate, reduced glutathione, oxidized glutathione, reduced coenzyme Ⅱ, and oxidized coenzyme Ⅱ in the leaves of naked oats; whereas the ratio of reduced glutathione to oxidized glutathione was increased significantly. Spraying with sodium hydrosulfide significantly increased the levels of glucose, fructose-6-phosphate, 3-phosphoglyceric acid, lactate, α-ketoglutaric acid, fumarate, malate, glutamine, 6-phosphogluconolactone, and sedoheptulose-7-phosphate in the leaves of naked oats under saline-alkali stress, and significantly decreased the asparagine content. The levels of trans-cinnamic acid and syringaldehyde in the leaves of naked oats under non-saline-alkali conditions were significantly decreased by spraying with sodium hydrosulfide. Saline-alkali stress significantly reduced the content of trans-cinnamic acid in the leaves of naked oats, and markedly increased the levels of benzoic acid, p-hydroxycinnamic acid, and trans-ferulic acid. Spraying with sodium hydrosulfide significantly increased the levels of 4-hydroxybenzoic acid and vanillin in the leaves of naked oats under saline-alkali stress, and remarkably decreased the levels of salicylic acid and 4-hydroxy-3,5-dimethoxycinnamic acid.There was no significant increase in spike number, spike boll number, thousand-grain weight, and biological yield of naked oats under saline-alkali stress as a result of spraying with sodium hydrosulfide; however, sodium hydrosulfide significantly alleviated the decrease in spike grain number and grain yield induced by saline-alkali stress. These results indicate that exogenous hydrogen sulfide participates in the regulation of sugar catabolism and phenolic acid levels in naked oats, which can enhance the saline-alkali tolerance of naked oats. The increasing effect of exogenous hydrogen sulfide on organic acid levels in the sugar decomposition pathway and the unique regulatory effect on phenolic acids may play an important role in enhancing the saline-alkali tolerance of naked oats.
Effect of planting and returning Vicia villosa on soil active organic carbon and yield of subsequent maize in coastal saline soils
LI Kexin, WANG Guangmei, ZHANG Xiaodong, ZHANG Haibo, SHI Yiming, JI Zengcheng, ZHOU Zhiyong
, Available online  , doi: 10.12357/cjea.20220759
Abstract(34) HTML (18) PDF(2)
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Fallow in the winter-spring season is becoming a common practice in the Yellow River Delta region, influenced by heavy soil salinization, scarce available water in spring, and reduced precipitation induced by climate change. However, fallow in winter can cause ecological problems such as soil erosion and secondary salinization, which will inevitably lead to environmental degradation once large areas of crop land being fallow. This study investigated the influence of planting and returning Vicia villosa (V. villosa treatment) in the winter-spring season on soil physicochemical properties, especially on active organic carbon and yield of subsequent maize crops compared to fallow, to provide a reference for the application of cover crops in improving saline-alkali land productivity in the Yellow River Delta. The field experiments were conducted from September 2020 to October 2021. For the V. villosa treatment, V. villosa was sown in September 2020 and returned to the soil as green manure during its blooming period in May 2021, and maize was sown in July 2021. For the fallow treatment, the experimental area remained fallow before maize sowing, and maize was sown on the same day under the same cultivation management as for the V. villosa treatment. The results showed that during the growing period of V. villosa, the soil electrical conductivity (EC) decreased, and the readily oxidizable organic carbon content (ROC) increased. When V. villosa was returned to the soil, soil pH decreased, and soil nutrients and active organic carbon contents improved significantly compared with fallow. During the entire experimental period, the average pH of the V. villosa treatment decreased by 0.12, and the average contents of total nitrogen (TN), total phosphorus (TP), organic carbon (SOC), ROC, dissolved organic carbon (DOC), and ROC/SOC of the V. villosa treatment increased by 15.1%, 5.5%, 6.3%, 99.1%, 8.2%, and 89.9%, respectively, compared with those of fallow treatment. However, the average EC values for the two treatments were approximately equal. Compared to the fallow treatment, the V. villosa treatment significantly increased the subsequent maize straw biomass, grain yield, and total aboveground biomass by 25.3%, 15.9%, and 21.4%, respectively, indicating a better yield improvement effect. Principal component analysis showed that maize yield was positively correlated with soil TN, SOC, DOC, and ROC, but negatively correlated with pH and EC. EC and soil organic carbon components were strongly correlated before the return of V. villosa. However, TN had the greatest influence on soil organic carbon components in each maize growing period after V. villosa return, followed by pH. The content of each organic carbon component increased with increasing TN content and decreasing pH. This study indicates that planting and returning V. villosa in the winter and spring seasons could increase soil active organic carbon content by increasing soil TN and decreasing pH, which comprehensively enhanced maize yield. Overall, in the Yellow River Delta, the introduction of V. villosa as a cover crop has prominent advantages in soil amelioration and yield improvement of subsequent crops when compared to fallow in the winter-spring season, which could be considered as the optimal planting pattern for the comprehensive utilization of saline-alkali land.
Regulation of fulvic acid on tomato yield and quality under saline water irrigation
CHEN Pei, WANG Jintao, DONG Xinliang, TIAN Liu, ZHANG Xuejia, LIU Xiaojing, SUN Hongyong
, Available online  , doi: 10.12357/cjea.20220178
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In view of the problem that the lack of freshwater resources restricts crop growth in saline-alkali areas around Bohai Sea, the regulation effect of fulvic acid on the yield and quality of tomato under saline water irrigation was studied according to the regional salt water resource endowment. In this study, the integrated water and fertilizer test method for substrate cultivation was adopted, and three fulvic acid concentrations were set: 0 mg·L−1, 450 mg·L−1, and 900 mg·L−1; five saltwater concentrations : 1 g·L−1, 3 g·L−1, 5 g·L−1, 7 g·L−1, 9 g·L−1, a total of 15 treatments. The results showed that compared with no fulvic acid addition, fulvic acid addition had obvious yield-increasing effects on tomatoes under different saline water concentrations. The yields of 450 and 900 mg·L−1 fulvic acid were increased by 6.14%−21.08% and 12.83%−34.63%, respectively. With the increase of salt water concentration, tomato fruit weight, fruit number per plant, water consumption, yield water use efficiency, vitamin C and lycopene content per fruit dry matter decreased significantly, and fruit reducing sugar increased first and then decreased. Under saline water irrigation, the application of 450 and 900 mg·L−1 fulvic acid could increase tomato single fruit weight, fruit number per plant, water consumption, yield water use efficiency, Vitamin C, lycopene and reducing sugar content per fruit dry matter. With the increase of fulvic acid concentration, proline content and K+/Na+ in tomato leaves increased significantly, while MDA and Na+ decreased significantly. The yield and water consumption per plant were positively correlated with K+/Na+, and negatively correlated with proline, malondialdehyde and Na+; Vitamin C and lycopene in tomato fruit were significantly positively correlated with K+/Na+, and negatively correlated with malondialdehyde and Na+; There was a significant negative correlation between reducing sugar and malondialdehyde and Na+. The above results showed that fulvic acid could alleviate the inhibition of salt water irrigation on tomato yield, and also promote the yield water use efficiency, Vitamin C, lycopene and reducing sugar content of dry matter per unit fruit. It could alleviate salt stress mainly by promoting the accumulation of organic osmotic adjustment substance proline, increasing K+/Na+ and reducing the production of membrane lipid peroxidation product malondialdehyde.
Effects of biochar and conditioner on pioneer crops planted in coastal barren severe saline-alkali soil
YANG Lilin, TANG Shuda, ZHU Xiangmei, HOU Jianwei
, Available online  , doi: 10.12357/cjea.20220799
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Mechanisms that assist in reclaiming the coastal barren severe salt-affected soils in arid and semi-arid regions when treated with soil amendments have not been well characterized. Aiming at biological improvement, development, and utilization of barren severe saline-alkali soils, a field experiment was conducted to apply biochar and soil conditioner for pioneer crops planted in the coastal barren severe saline-alkali area of the North China Low Plain. Six treatments included single or combined application of two-level biochar rates (0 and 1.25 kg∙m2) and three-level soil conditioner rates (0, 0.83, and 1.66 kg∙m2) at the start of the experiment. Biochar significantly inhibited younger plant growth at the early stage of oil sunflower but had no marked impact on grown-up plants during the later stage, and grain quantity and yield. Meanwhile, biochar increased N and P contents in stems, leaves, and shells, the K content in stems, shells, and kernels of oil sunflowers, and promoted the transfer of K and Ca from leaves to kernels. However, biochar impeded Mg uptake and decreased the Mg content of stems and sunflower discs but had no significant effect on Na uptake by oil sunflowers. Soil conditioner significantly increased the growth of stems, leaves, and discs, and improved the grain yield. In addition, it promoted P transfer to the kernel. At an application rate of 1.66 kg∙m2, the soil conditioner promoted the transfer of N to the kernel preferentially and significantly improved the Ca content of stems, leaves, and discs, while increasing the Mg content of stems. Co-application of biochar and soil conditioner weakened the negative impact of biochar on plant growth, increasing uptake of N, P, K, and Ca, and facilitating transferring N, P, and K to the kernel, whereas reducing Na and Mg uptake for oil sunflower. Oil sunflowers, other than cotton, as a pioneer crop, are more suitable for planting in coastal barren, severely saline-alkali areas. The results from this preliminary study show that the co-application of biochar and soil conditioner provides an alternative method of waste recovery, converting straw resources into a value-added product, development, and bio-reclamation for coastal barren severely salt-affected soils, and the option of salt-tolerant pioneer crops that are adaptive to coastal areas.
Analysis of Quality and Quantity Characteristics of Saline ice Meltwater under Different Pretreatment
, Available online  , doi: 10.12357/cjea.20220924
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Development theory and new system of technology of high-efficient eco-agriculture in rural area of Fujian Province
LIN Yi, YE Jing, CHEN Hua, WANG Yixiang, LIU Penghu, WENG Boqi
, Available online  , doi: 10.12357/cjea.20220928
Abstract(15) HTML (4) PDF(3)
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As the demands of high-efficient eco-agriculture have enriched the content of building an agricultural powerhouse, its in-depth exploration and continuous improvement are essential measures and operation carriers to implement the rural revitalization strategy. Basis of the development experience of secure an adequate supply, resource conservation, and environment-friendly agricultural, the study extended and expanded the scientific and theoretical connotations of high efficiency ecological agriculture, constructed main framework of “county-regional-basin” high efficiency eco-agriculture construction, and analyzed the construction ideas and development goals of high efficiency eco-agriculture in the process of rural revitalization. High-efficient eco-agriculture was the improvement and sublimation of ecological agriculture. Following the construction requirements to improve the quality and efficiency of modern agriculture and the construction of a strong agricultural province of Fujian Province, the study proposed the practical countermeasures of new cluster construction for the integrated development of rural ecological industrialization and industrial ecology in Fujian Province; according to local conditions to create a harmonious coexistence of humans and nature, which is suitable for work and livable rural integration; deeply explored and established a new technology system optimization construction and implementation countermeasures for the new management mechanism and entrepreneurial system of carbon-neutral in rural areas of Fujian Province. In addition, the study explored and created a production and operation model of rural industrialization + ecological “double synergy” development and agricultural economic benefits + ecological benefits “double coordination” development; adjust measures to local conditions to promote the transformation and upgrading of high efficiency eco-agriculture with regional characteristics, which is an effective path to comprehensively promote rural revitalization.
Study on shallow mild saline groundwater use safety in winter wheat irrigation based on subsurface drainage system in coastal area of Hebei Province in China
GAO Hui, ZHAO Liang, LIU Bin, FU Tonggang, LIU Jintong
, Available online  , doi: 10.12357/cjea.20220937
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There is a shortage of irrigation water resources in the coastal saline-alkali cultivated land of Hebei Province, which is rich in shallow saline water resources. Proper saline water irrigation during the critical period of winter wheat growth can alleviate the irrigation crisis in this area. In this paper, coastal saline-alkali land of Hebei province was selected as the research object, and Maying Village of Nandagang Industrial Park located Cangzhou city was selected as the test base, shallow mild saline water winter wheat field irrigation experiment was carried out in order to analysis the effects of saline irrigation on winter wheat yield and soil salt content. The results indicated that: 1) Mild saline water irrigation in the joint-heading stage of winter wheat can increase the yield of winter wheat in coastal saline-alkali land of Hebei province, which was more than 1.5 times that of dry wheat. 2) Based on subsurface drainage system, mild saline water irrigation would not cause salt accumulation in the soil surface layer, when the rainfall is maintained under multi-year average rainfall conditions in rainy season, the average soil salt content after the 2016−2018 rainy season was 2.86 g∙kg−1, 1.60 g∙kg−1 and 1.38 g∙kg−1, and the degree of soil salinization was reduced year by year after two consecutive years of salt water irrigation. The conclusion was that: the shallow saline water resources in the coastal saline-alkali land of Hebei province could be safely utilized in the irrigation of winter wheat. On this basis, we took Cangzhou City of coastal region of Hebei Province as an example, the analysis of shallow salt water resource prospects shows that: only winter wheat water demand was considered in Cangzhou City, irrigation water demand deficit was at least 1.7×108 m3 in Cangzhou City. The shallow saline water resources of 1−5 g·L−1 in Cangzhou City are abundant, which can meet the deficit in terms of water resources; the feasibility of mild saline water irrigation for winter wheat makes the planting mode of one crop of spring maize a year in some cultivated land become the planting mode of two crops of winter wheat-summer maize a year, and the sown area of winter wheat can be increased by at least 9000hm2 in Cangzhou. The results provided scientific basis for the safe utilization of coastal mild saline water resources, grain yield guarantee and soil sustainable development in coastal area of Hebei province.
Effect of underground brackish water depth on soil water-salt distribution and water consumption of winter wheat
ZHANG Xuejia, WANG Jintao, DONG Xinliang, TIAN Liu, LOU Boyuan, LIU Xiaojing, SUN Hongyong
, Available online  , doi: 10.12357/cjea.20220882
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Production of winter wheat in the low plains around the Bohai Sea faces the constraint of freshwater resource shortage, and the efficient and safe use of the relatively abundant shallow brackish water resources is of great importance for sustainable agricultural development. Soil column simulation experiments were conducted at the Nanpi Ecological Agricultural Experiment Station of the Chinese Academy of Sciences in 2021–2022. Four treatments, including no groundwater but freshwater (487.5 mm) irrigation treatment (CK) and underground brackish water depths of 0.5 m (GW1), 1.0 m (GW2), and 1.5 m (GW3) with 20 mm freshwater irrigation were applied, with three replications for each treatment. This experiment investigated the characteristics of soil water, salinity content, and water use in winter wheat. The results showed that the distribution of soil water and salt in the surface soil (0–10 cm) gradually decreased with increasing groundwater depth. Compared with the CK treatment, the surface soil water content of the GW1 treatment significantly increased by 30.9% and that of the GW3 treatment significantly decreased by 79.3%, whereas there was no significant difference for the GW2 treatment. Compared with the CK treatment, the salinity of surface soil in the GW1 and GW2 treatments significantly increased by 3.4 g·kg−1 and 2.0 g·kg−1, respectively, whereas there was no significant difference in the GW3 treatment. Salt in the GW1 and GW2 treatments mainly accumulated in the surface soil, whereas that in the GW3 treatment was low and mainly accumulated at a depth of 30–50 cm. The evapotranspiration of winter wheat significantly decreased with increasing groundwater depth. The evapotranspiration of winter wheat significantly increased by 50.2% and 20.3% under the GW1 and GW2 treatments, respectively, compared to CK, and there was no significant difference between the GW3 and CK treatments. The grain yield of the GW3 treatment was the highest, which was significantly increased by 38.04% compared with that of the CK treatment. The highest values for water use efficiency at the biomass and yield levels in the GW3 treatment were significantly higher than those in the CK treatment by 26.7% and 40.1%, respectively. The above results show that 1.5 m is the upper limit of the suitable groundwater depth for winter wheat growth in underground brackish water shallow burial areas when the mass concentration of brackish water is 3 g·L−1 and groundwater depth is 0.5–1.5 m. Under these conditions, the surface salinity and crop evapotranspiration were the lowest, and the yield and water use efficiency were the best.
It is necessary to develop the slow and controlled release fertilizer continuously
ZOU Guoyuan, CAO Bing, LI Lixia, XIAO Qiang, LI Jijin
, Available online  , doi: 10.12357/cjea.20230038
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Development of slow-release and controlled-release fertilizers is an important way to reduce fertilizer rate and improve their use efficiency, and plays an important role in supporting the sustainable development of modern agriculture. This paper reviewed the 32 years’ research work in the fertilizer area in Institute of Plant Nutrition, Resources and Environment, Beijing Academy of Agricultural and Forestry Sciences. The research process, team organization, product innovation and fertilization service of different fertilizers from laboratory to field were introduced, and the future research directions were analyzed and prospected. Since 1991, the Institute has started the research and development of slow-release and controlled-release fertilizers. In the initial stage (1991-1998), zeolite-coated fertilizer and resin-coated fertilizer were developed successively. During the rapid development stage (1999-2015), controlled-release fertilizer products have gradually realized industrialization and driven the development of the industry. During the stable promotion period (2016-), bio-based coated controlled-release fertilizers have been paid attention to and made great progress. Zeolite-coated urea is a kind of inorganic coated fertilizer with natural zeolite as coating agent. Its functional characteristics were investigated, and a series of fertilizer formulations and application techniques were developed. Resin-coated fertilizer is made by spraying a layer of semi-permeable or impermeable material on the fertilizer surface to achieve controlled release of nutrients. The production process of polyolefin resin type is divided into three parts: dissolution of coating material in solvent, granule coating and solvent recovery. In 1998, the institute developed a spouted bed coating equipment with an annual output of 2000 t resin-coated fertilizer. Thermosetting resin coated fertilizer is another major type, for which solvent-free in-situ reaction film-forming process is commonly used. The high-efficiency mixed spraying method with self-cleaning function was proposed, and semi-automatic and continuous automatic productions were developed one after another. At the same time, the nutrient release prediction technology and on-line rapid detection technology were constructed for controlled-release fertilizer, and a series of special formula fertilizers and their application technology were developed. The innovation of slow-release and controlled-release fertilizers has served the precise nutrient requirements of crops from field to horticulture, and promoted the upgrading of fertilizer industry, reducing the fertilizer rate and enhancing fertilizer use efficiency, and even controlling non-point source pollution. In order to meet the realistic need of agricultural development, in the future, it is still necessary to continuously study the biodegradable coating materials for fertilizer products, the multi-stage continuously controllable release of nutrients, the innovative large-scale and continuous production processes, the on-line rapid detection technologies of product quality, and the special multi-component and controlled-release functional fertilizers for crops.
Effects of the content dynamics of NO3-N and phenolic acids in soil on root growth of cotton seedlings under the return of wheat straw
LI Jianan, YANG Changqin, SHU Hongmei, ZHANG Guowei, WANG Xiaojing, LIU Ruixian, CHEN Jiamin, WANG Feibing, CHEN Xinhong
, Available online  , doi: 10.12357/cjea.20220918
Abstract(21) HTML (4) PDF(3)
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As natural supplements containing valuable nutrients, such as carbon, nitrogen, phosphorus and potassium, etc., crop straws are often incorporated into soils in sustainable agriculture. Nitrate nitrogen (NO3-N) is the main form of nitrogen released from crop straw under dry farming. For cotton, NO3-N is not only the main form of nitrogen absorption by root, but also the regulation signal of plant root growth. Straw return can cause net N immobilization resulting from high C/N of crop straw, which affect the availability of soil and fertilizer N, thus inhibiting the early growth of crops and even decreasing crop yield. Meanwhile, straw return also releases a large amount of phenolic acid, inhibiting seed germination and root growth of crops. The aim of this study is to reveal the mechanism that the concentration dynamics of NO3-N and phenolic acid in soil affect the growth of cotton seedlings under the return of wheat straw. Based on the 11-year return of wheat straw, field experiment was conducted in 2021 and 2022 at the experimental station of Jiangsu Academy of Agricultural Sciences in Nanjing, Jiangsu Province, China. Two treatments of wheat straw removal (CK) and wheat straw return (S) were applied. The concentrations of NO3-N and phenolic acid of soil in subsequent cotton field, the NO3-N content and nitrate reductase activity of cotton seedlings, the activity and morphology indexes of cotton root and the biomass of cotton seedlings were investigated. The results demonstrated that straw return increased the concentrations of NO3-N and phenolic acid contents in soil, and the effect on 0~20 cm soil layer was greater than that on 20~40 cm soil layer. With the delay of days after straw return, the concentrations of NO3-N and phenolic acid in soil increased first and then decreased, and reached the peak at 24 d−31 d after straw return. Within 31 d after straw return, the root activity, root NO3-N content, nitrate reductase (NR) activity, root biomass and morphological indexes of cotton seedlings under straw return treatment were significantly lower than those under CK treatment, but showed the opposite trend after 31 d of straw return. The correlation analysis showed that the concentrations of phenolic acid in 0~20 cm soil was significantly and negatively correlated with the root activity, NO3-N content of root, the length, diameter and surface area of cotton root and the aboveground biomass. The NO3-N content in different soil layers was positively correlated with the indexex of morphology and physiology and the biomass of cotton seedling, but did not reach a significant level. In sum, the effect of straw return on the growth of cotton seedlings showed a trend of "first inhibition and then promotion". Within 31 days after straw return, the "inhibition effect" of phenolic acid of soil on the growth of cotton seedlings was greater than that of "fertilization effect" of straw. Higher phenolic acid content reduced the root activity and root growth of cotton seedlings, inhibiting the absorption and utilization of NO3-N in cotton seedlings. After 31 d of straw return, the "fertilization" effect of straw was greater than the "inhibition" effect of phenolic acid, which promoted the root growth of cotton seedlings.
The modernization of China’s eco-agriculture: connotation, task and path
ZHAO Guishen
, Available online  , doi: 10.12357/cjea.20230036
Abstract(12) HTML (5) PDF(3)
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As China’s agriculture is in a critical period of transformation of modernization, it is substantially necessary to further recognize the connotation, task and path of China’s eco-agriculture in the new era and to reach a common understanding on it. In our view, the modern eco-agriculture in China can be considered as the essential path to modernization of China’s agriculture due to its originating from China’s traditional agriculture, absorbing modern achievements in science and technology and applying modern management system of industry, which also give new meaning to China’s eco-agriculture. However, the modernization of China’s eco-agriculture is still facing huge tasks and challenges of ensuring food security, ecological safety, nutrition security, inheritance of traditional farming culture and realizing common prosperity. Consequently, through maintaining a systematic approach, upholding fundamental principles and breaking new ground, China’s eco-agriculture should make great breakthroughs aiming at innovating the typical model of ecological agriculture, strengthening research and development of agricultural green inputs, accelerating the development and application of new equipment for ecological agriculture, promoting the operation capacity of industrial chain, and improving the policy and mechanism of ecological compensation. The practical path would focus on maize and soybean intercropping, rice-fish co-culture, green house of planting-breeding, indoor vertical eco-farm in innovation of typical model; new slow/ controlled release fertilizer, new liquid fertilizer, biochar based fertilizer, microbial fertilizer, micronutrient fortifier, green smart fertilizer, green manure crop, photo-micro fertilizer, CO2 gas-fertilizer, biological pesticide, natural enemies and pollinating insects, new insect trapping equipment, biodegradable mulch film and soil remediation technology & product in green inputs area; advanced agricultural basic equipment, intellisense technology, cloud-brain technology, intelligent control/management technology, internet of things based on integrated ground-air-space, platform of space breeding laboratory, recycling system of organic waste, integrated biological control system for diseases, insect pests and weeds, indoor vertical farming system in agricultural equipment area; community supported agriculture, ecological leisure and health care, cloud ecological farm, green international trade in operation of modern industrial chain; and Gross Ecosystem Product (GEP), Gross Economic-Ecological Product (GEEP) and Environmental, Social and Governance (ESG) in agricultural policy making etc. In summary, based on China's actual condition, there is an urgent need to innovate and develop the modern industrial & technological system of China’s eco-agriculture relying on two-wheel drive of agricultural science & technology and rural reform, China’s eco-agriculture would provide Chinese solutions for the sustainable development of world agriculture in future decades.
Effects of subsurface organic ameliorant combined with film mulching on saline soil organic and inorganic carbon in Hetao Irrigation District
SONG Jiashen, ZHANG Hongyuan, CHANG Fangdi, YU Ru, ZHANG Xia, WANG Weini, SU Wei, LI Yuyi
, Available online  , doi: 10.12357/cjea.20220749
Abstract(26) HTML (5) PDF(2)
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Soil organic carbon (SOC) and inorganic carbon (SIC) are important carbon pools involved in the global carbon cycle. Subsurface (10−30 cm) organic ameliorant (OM) combined with film mulching (PM) is an effective measure to optimize the physical structure and regulate water and salt movement of saline soil in arid areas. However, the distribution of SOC and SIC in the 0–60 cm soil layer and their relationship with soil physicochemical properties remain unclear. This study was based on a 6-year micro-field experiment of saline soil at the Yichang Experiment Station, which is located in the Hetao irrigation area of Inner Mongolia. Four treatments were set: conventional control (CK), OM, PM, and OM+PM. The levels of SOC, SIC, total carbon (TC), and soil physicochemical property indexes (soil moisture, salinity, pH, and total nitrogen) in the 0−60 cm (0−20 cm, 20−40 cm, and 40−60 cm) soil layer after the harvest of Helianthus annuus during 2019–2020 were measured, and the variation characteristics and influencing factors of TC, SOC, and SIC were analyzed. The results showed that the TC content in the 0−60 cm soil layer and SOC in the 0−40 cm soil layer were mainly affected by OM treatment compared with PM treatment (P<0.01). The SIC content in the 0−40 cm soil layer was affected by OM treatment (P<0.001), PM treatment (P<0.05, except for the 20−40 cm soil layer in 2019), and their interaction (P<0.001); however, the 40−60 cm soil layer was mainly affected by OM treatment (P<0.05). Compared to CK and PM treatments, OM and OM+PM treatments significantly increased SOC content in the 0−40 cm (0−20 cm and 20−40 cm) soil layer by 31.9%−195.6% (P<0.05), and significantly increased SOC content in the 40−60 cm soil layer by 33.7%−49.4% (P<0.05) only in 2020, but significantly decreased SIC content in the 0−40 cm (0−20 cm and 20−40 cm) by 9.9%−35.0% (P<0.05). Based on the changes in SOC and SIC, compared with CK treatment, OM+PM treatment significantly increased TC content in the 20−60 cm (20−40 cm and 40−60 cm) soil layer in 2019 by 10.4%−39.4% (P<0.05), and the TC content of the 0−20 cm layer in 2020 was significantly increased by 13.0% (P<0.05). The regression analysis results further indicated that the dominant factor of the total carbon pool changed from SIC to SOC with the OM+PM treatment. The results of redundancy analysis showed that soil physicochemical properties were the main factors affecting soil TC, SOC, and SIC (explaining 60.7%−91.9% of the variation), and total nitrogen and pH were the main factors affecting soil TC, SOC, and SIC in the 0−40 cm layer, whereas soil TC, SOC, and SIC in the 40−60 cm layer were mainly affected by salinity and pH. Correlation analysis showed that changes in SOC and SIC were completely opposite. Soil organic carbon was positively correlated with total nitrogen and negatively correlated with salinity and pH (P<0.01). Soil inorganic carbon was negatively correlated with total nitrogen and positively correlated with pH (P<0.01). Therefore, OM combined with PM (OM+PM) could compensate for the loss of SIC and realize carbon accumulation by increasing SOC, which is an effective strategy to increase the carbon sequestration potential of saline soil in this region.
Research Progress of Rural Regional System Carbon Effect from The Perspective of Double Carbon
, Available online  , doi: 10.12357/cjea.20220798
Abstract(16) PDF(0)
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Study on Spatiotemporal Changes of Physiological and Biochemical Indexes and Total Flavonoids of Tetrastigmahemsleyanum in response to blue and purple monochromatic light treatment
, Available online  , doi: 10.12357/cjea.20210116
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Growth characteristics and soil respiration rates with different coverages of Suaeda salsa at coastal beaches
LI Yongtao, WANG Zhenmeng, WEI Haixia, ZHOU Jian, WANG Lili, ZHANG Jun, LYU Xingjun, YANG Qingshan, WANG Yuanbo
, Available online  , doi: 10.12357/cjea.20220727
Abstract(45) HTML (17) PDF(2)
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Coastal beaches are one of the most important components of coastal wetlands. Studies on vegetation growth characteristics and soil respiration in coastal beaches are essential for evaluation of the ecological and environmental functions of coastal wetlands. In the present study, differences in vegetation growth, root distribution, and soil respiration rate of Suaeda salsa with four coverage types (bare flat and low-coverage, medium-coverage, and high-coverage) were determined to explore the impact of vegetation coverage on the growth characteristics of S. salsa and soil respiration rates at the coastal beach of the Yellow River Delta. Significant differences were observed in the soil physicochemical properties and vegetation growth of S. salsa on coastal beaches with different coverages. Soil salt content and bulk density were lower in various coverage areas than those in bare flats, whereas soil porosity and nutrients contents were greater than those in bare flats. The growth indices of S. salsa, such as biomass, plant height, and branch number, were positively correlated with vegetation coverage (P<0.05), indicating better growth in soils with higher vegetation coverage. The underground S. salsa biomass in saline land was mainly distributed in the 0–20 cm soil layer, showing a shallow distribution pattern. Roots with a 2–5 cm diameter were dominant components, accounting for 72.53%, 59.72%, and 39.30% of the underground biomass in the low-, medium-, and high-coverage areas, respectively. The root length, surface area, tip number, branch number, and cross number of fine roots increased with coverage, and the differences in these indices between the different coverage areas were significant (P<0.05). Soil respiration rates were low, at 0.26–1.01 μmol∙m2∙s1, owing to the low soil organic carbon content and microbial activity in the study area. Soil respiration rates were significantly affected by vegetation coverage and showed an increasing order of value with coverage (high-coverage area > medium-coverage area > low-coverage area > bare area). Soil respiration rate was measured as an evident daily change as a low-high-low single peak curve, with the maximum value appearing at 12:00 in the low-coverage and bare areas and at 14:00 in the high- and medium-coverage areas. S. salsa growth indicators were significantly negatively correlated with soil salt content, demonstrating that soil salt was the main limiting factor for vegetation growth in coastal wetlands. However, the soil salt content was affected by vegetation coverage. Soil respiration rate was highly and positively correlated with plant growth indicators. We concluded that soil physicochemical properties, vegetation growth of S. salsa, and soil respiration rate were significantly affected by vegetation coverage on the coastal beach of the Yellow River Delta. High vegetation coverage improves soil properties and vegetation growth, further promoting ecological restoration in coastal wetland areas. The results of this study provide a theoretical basis for the vegetation and ecological restoration of coastal beaches in the Yellow River Delta. However, long-term field observations are recommended to determine the permanent effects of vegetation coverage on vegetation growth characteristics and soil respiration on coastal beaches.
Effects of saline water irrigation on soil quality and crop production: a review
SUN Hongyong, ZHANG Xuejia, TIAN Liu, LOU Boyuan, LIU Tong, WANG Jintao, DONG Xinliang, GUO Kai, LIU Xiaojing
, Available online  , doi: 10.12357/cjea.20220899
Abstract(34) HTML (23) PDF(9)
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Fresh water is a basic natural and important strategic resource. Most salt-affected soils are distributed in arid and semi-arid areas, and a shortage of freshwater resources is the most important limiting factor for sustainable agricultural development. However, the relatively rich saline water, land, solar, and thermal resources in saline-alkali areas provide sustainable regional agriculture development potential. To address challenges of soil quality decline and crop yield reduction induced by saline water irrigation, this study summarizes the factors affecting the safe utilization of saline water and the impact mechanism of saline water irrigation on soil hydraulic characteristics, soil physicochemical properties, crop growth, grain yield, and quality. First, freshwater, brackish water, and saline water classifications were as previously described. Factors affecting the safe utilization of saline water include saline water quality, irrigation amount, irrigation methods, and the groundwater table. Second, saline water irrigation has negative effects on soil quality, which increases the salinity of the surface soil, destroys the soil structure, and further affects the soil hydraulic characteristics, water infiltration, and salt distribution, affecting greenhouse gas emissions. Third, crops grow slowly and die because of the lower photosynthetic rate after saline water irrigation. However, most of the treatments irrigated using saline water improved the grain yield compared with the rainfed treatment and improved the grain quality under optimal salinity water. Furthermore, based on field experiments, most crops have optimal saline water thresholds. Finally, we analyzed the regulatory effects of agricultural practices such as organic fertilizer application, straw mulching, tillage, saline water irrigation schedules, cropping systems, and salt-tolerant crop planting. In the future, to ensure food and water security, it is necessary to conduct the mechanism process and technology research, and develop model to demonstrate the effects of saline water deficit irrigation and water-fertilizer-salt comprehensive regulation on the change in soil quality after saline water irrigation, and the effects of saline water precision irrigation on crop production and the ecosystem, which will provide a theoretical basis and technical support for the sustainable development of agriculture in water-deficient and saline areas.
Progress of research on the improvement of saline-sodic soil using acidic substances
MIAO Yue, YANG Fan, WANG Zhichun, SHAO Xiwen, GENG Yanqiu
, Available online  , doi: 10.12357/cjea.20220675
Abstract(87) HTML (31) PDF(8)
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As a reserve land resource in China, saline-sodic soil has great utilization potential; if properly developed and utilized, it will produce great benefits. Chemical methods are important for improving saline-sodic soils. In the early days, calcium-containing preparations, such as gypsum and phosphogypsum, were used to replace the exchangeable sodium adsorbed on soil colloids by adding exogenous calcium. However, saline-sodic soils are rich in calcium carbonate. Acid substances, as one of the chemical amendments, can be hydrolyzed to produce hydrogen ions. This reduces the pH of saline soil, which is conducive to dissolving calcium carbonate in soil and providing calcium sources for replacing exchangeable sodium in soil; thus reducing the addition of exogenous calcium materials and reducing the improvement cost. Based on a comprehensive analysis of domestic and foreign studies on the physical properties, saline properties, nutrient utilization, and crop yield of saline-sodic soil, this paper summarized the improvement mechanism and practice of the application of acid substances to saline-sodic soil, and forecasted its future development trend to provide a reference for saline-sodic soil management and agricultural utilization.
Screening of accumulating plants in farmland surrounding typical lead and zinc smelting enterprises
HE Mengke, GUO Junmei, YANG Junxing, ZHENG Guodi, CHEN Tongbin, MENG Xiaofei, LI Yufeng, LIU Jie
, Available online  , doi: 10.12357/cjea.20220711
Abstract(21) HTML (6) PDF(2)
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As one of the most important lead (Pb) and zinc (Zn) smelting production bases in China, the heavy metal content in the farmland surrounding the enterprises in Jiyuan City of Henan Province seriously exceeded the national standard due to the backward technology and large pollutant discharge. In order to explore the characteristics of heavy metal contamination in farmland around Pb and Zn smelting enterprises in Jiyuan City, select the dominant plants for remediation and safe utilization of heavy metal-contaminated farmland, and establish a preliminary remediation model, field experiments were conducted on farmland surrounding Pb and Zn smelting enterprises in Jiyuan City. The study included investigating the characteristics of cadmium (Cd), Pb, and arsenic (As) pollution in soil, analyzing the heavy metal content in main agricultural products, selecting 17 kinds of heavy metal-accumulating plants for field cultivation, and studying their biomass, heavy metal contents, enrichment coefficient, extraction amount, and remediation efficiency. The results showed that the average content of Cd, Pb, and As in soil was 2.22 mg·kg−1, 173.1 mg·kg−1 and 18.38 mg∙kg−1, respectively, which were mainly distributed in the cultivated layer. Among them, the content of Cd and Pb exceeded the risk screening values in the Environmental Quality Standard for Soils (GB 15618—2018), and the single factor pollution index reached 3.71 and 1.02, respectively. In terms of the wheat and maize cultivated on the contaminated farmland, the content of Cd, Pb, and As in maize seeds did not exceed the values in the National Food Safety Standards (GB 2762—2017), but the Cd and Pb content in wheat seeds exceeded the standards, while the exceeding rates both reached 100%. In plant cultivation experiments, the biomass and heavy metal enrichment capacities of the 17 kinds of accumulating plants differed significantly. The biomass of Amaranthus hypochondriacus was the highest, reaching 29 598 kg·hm−2, which was 46.61 times that of Noccaea caerulescens (635 kg·hm−2). The contents of Cd, Pb, and As in the 17 plant species were 2.90−30.90 mg·kg−1, 7.81−93.1 mg·kg−1, and 3.76−22.9 mg·kg−1, respectively. The bioconcentration factors of Cd, Pb, and As were 1.31 to 13.92, 0.05 to 0.54, and 0.20 to 1.24, respectively. Helianthus annuus ‘S606’ had the largest Cd, Pb, and As comprehensive bio-concentration index of 2.3. Combining plant biomass and enrichment capacity, 17 plant species showed clear differences in the removal efficiency of contaminated soil. Cluster analysis showed that Amaranthus hypochondriacus, Brassica napus ‘Zhongyou 1000’, and Helianthus annuus ‘S606’ had higher Cd and Pb accumulation and remediation capacities in soil. The removal efficiency of these three species was higher than 1.90% for Cd and 0.07% for Pb, showing a promising potential for remediation of Cd and Pb-contaminated soils. In addition, Brassica napus and Helianthus annuus can be further processed to produce edible oil, feed, or fertilizer, which can bring economic benefits while remediating soil. In conclusion, the farmland surrounding the Pb and Zn smelting enterprise in Jiyuan City was typically light to moderately contaminated with Cd and Pb. In response to this situation, two technical modes of heavy metals-contaminated farmland remediation were proposed: Amaranthus hypochondriacus-Brassica napus rotation remediation mode and Helianthus annuus monoculture remediation mode. Both modes can achieve high remediation efficiency and were viable and extendable.
Peaking process and decoupling analysis of carbon emissions of crop production in China
WU Haoyue, ZHOU Lei, HE Yanqiu, LIU Lu, MA Jinshan, MENG Yue, ZHENG Xiangjiang
, Available online  , doi: 10.12357/cjea.20220864
Abstract(25) HTML (8) PDF(6)
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Exploring the peaking process of carbon emissions of crop production provides a basis for greenhouse gas emission mitigation. Existing studies have generally found that the carbon emissions of crop production in China reached an inflection point in 2015. Nonetheless, it is far from reliable to judge whether the peak was reached without verifying the specific peaking process by statistical approaches. To better understand the peaking process, this paper calculated the carbon emissions of crop production in 30 Chinese provinces from 2000 to 2020 with four carbon sources considered, including agricultural materials, rice paddies, soil management, and straw burning. Then, the peaking process of carbon emissions was explored from both national and provincial levels. The Tapio decoupling index was used to verify the relationship between carbon emissions and economic output. The results show that: (1) The total carbon emissions of crop production in China had an annual average of 233.269 Mt, increasing from 200.020 Mt to 242.819 Mt during the study period, which peaked at 262.647 Mt in 2015. The average annual change rate after reaching the peak was −1.560%, indicating the emissions entered the plateau. Over time, agricultural materials became the primary emission source with a proportion of 34.6% while soil management contributed the least with a proportion of 11.6% in 2020. (2) Carbon emissions of crop production were positively correlated with the cropping scale. Merely two provinces, Hunan and Henan, had the highest emissions over 20 Mt, five provinces, such as Hubei and Shandong, had the highest emissions distributing in 15~20 Mt, and other five provinces like Jiangxi and Sichuan had the highest emissions ranging from 10 to 15 Mt. In contrast, the highest emissions in 18 provinces were less than 10 Mt, especially in Beijing, Tianjin, and Qinghai, with emission peaks below 1 Mt. As far as the peaking process, the carbon emissions in 13 provinces, including Beijing and Tianjin, were in a state of decline, those of 10 provinces, such as Shanxi and Chongqing, entered a plateau, and those of seven provinces like Henan and Anhui hadn’t met their peak yet. (3) At the national level, the long-term relationship between carbon emissions and economic output showed a weak decoupling, while the short-term one had changed from weak decoupling to strong decoupling. At the provincial level, the short-term relationship had evolved from multi-type coexistence to mainly strong decoupling. Consequently, it is recommended that emission mitigation of crop production in China should be sped up by source and phase based on the peaking process and emission magnitude. The provinces that had emissions in the states of peaking and plateauing require additional attention, as their subsequent developments determined the overall emission reduction. In comparison, flexible space of emission mitigation can be given to the provinces of declining states, as many of them are accompanied by low emissions and optimistic momentum. Nevertheless, three high-emission provinces, Hubei, Jiangxi, and Shandong, had also reached peak emissions and began to decline, which may serve as an example for provinces with similar conditions. The findings provide local solutions to accelerate the peaking process of carbon emissions of crop production in China.
Influence of combined application of bioorganic fertilizer and chemical fertilizer on lettuce growth and soil environment
ZHANG Qing, HU Chunsheng, LIU Binbin, ZHANG Yuming, DONG Wenxu, LI Xiaoxin, LIU Xiuping, WANG Jing, ZHANG Ruiyuan, WU Kunyan, WU Jie
, Available online  , doi: 10.12357/cjea.20220642
Abstract(28) HTML (8) PDF(5)
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Irrational fertilization leads to soil degradation and output decline, and waste disposal affects the sustainable development of environment and resources. Bioorganic fertilizer showed outstanding advantages in plant growth promotion and soil fertility cultivation, which is beneficial to efficient utilization of resource and reduction of chemical fertilizer application, as well as the development of vegetable industries. In this study, bioorganic fertilizers specifically for experiment were made by fermentation after inoculating Bacillus licheniformis, B. amyloliquefaciens and B. megaterium into Chinese medicine residues respectively, and lettuce pot experiment in greenhouse was conducted to explore the influence of bioorganic fertilizer combined with chemical fertilizer on lettuce growth and soil environment. Six treatments were set, including three treatments where bioorganic fertilizer with 80% nitrogen content replaced chemical fertilizer [B. licheniformis + Chinese medicine residue organic fertilizer + chemical fertilizer (B1H), B. amyloliquefaciens + Chinese medicine residue organic fertilizer + chemical fertilizer (B2H) and B. megaterium + Chinese medicine residue organic fertilizer + chemical fertilizer (B4H)], one treatment where organic fertilizer with 80% nitrogen content replaced chemical fertilizer [Chinese medicine residue organic fertilizer + chemical fertilizer (H)] and chemical fertilizer treatment (CF), as well as no fertilizer treatment (CK). The growth indicators of lettuce including biomass and quality and soil environmental indicators including physicochemical properties and bacterial diversity were measured and analyzed. The results showed that: the comprehensive effect of fertilization measures on yield and quality improvement of lettuce and nutrient environment improvement of soil were both ranked as B4H>B2H>B1H>H>CF>CK. Compared with H, the fresh weight and content of chlorophyll, vitamin C and soluble sugar of lettuce in B4H were increased by 10.69%, 17.77%, 47.54% and 10.95% respectively, while the lettuce nitrate content in B4H was decreased by 52.00%, and the content of available phosphorus (AP), rapidly available potassium (AK), alkali hydrolyzed nitrogen (AN), microbial biomass carbon (MBC) and water dissolved organic carbon (DOC) in B4H were increased by 47.57%, 10.98%, 8.05%, 35.54% and 16.10% respectively, as well as the species richness and diversity increased by 7.68% and 0.85% respectively in B4H. Soil AP, AK and AN were the most important impact factors affecting lettuce growth, while pH, AP and AK were the most significant regulatory factors on soil bacterial community. Bioorganic fertilizer combined with chemical fertilizer affected lettuce growth and soil environment mainly by regulating these key factors in soil. Fertilization was beneficial to bacterial Alpha diversity promotion in lettuce rhizosphere soil, and higher bacterial Alpha diversity in rhizosphere soil performed promoting effect on lettuce yield and quality. As a whole, B4H was the optimal fertilization to the improvement of lettuce growth and soil environment, and field experiment could be carried out to do further study on it’s effect of growth promotion and fertility cultivation,as well as the environmental effect. This study proposed new theoretical support to the development of vegetable and bioorganic fertilizer industries, and was conducive to the implementation of green sustainable development strategy.
Effects of different salt and alkali stress on absorption, transportation, and metabolism of nutrient elements in cotton
LU Xiaoyu, GUO Jiaxin, TAO Yifan, YE Yang, GUI Chenghao, GUO Huijuan, MIN Wei
, Available online  , doi: 10.12357/cjea.20220581
Abstract(74) HTML (57) PDF(9)
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There are many types of saline-alkali land in Xinjiang, and salt accumulation is a serious problem. Therefore, this study aimed to explore the effects of different saline-alkali stresses on the absorption, transportation, and metabolism of cotton nutrients and to reveal the tolerance mechanism of cotton to different salt and alkali stresses to provide a theoretical basis for cotton cultivation on different types of saline-alkali land in Xinjiang. Four treatments were used in this study: control (CK), NaCl stress (CS), Na­2SO4 stress (SS), and alkali (NaHCO3+Na2CO3) stress (AS). The effects of different salt and alkali stresses on the content and metabolism of nutrient elements in cotton roots and leaves were explored using ionomics and metabonomics. Compared with CK, the total biomass of CS, SS, and AS treatments decreased significantly (P<0.05) by 51.7%, 47.8%, and 52.3%, respectively. Compared with CK, CS treatment significantly (P<0.05) increased the content of N in leaves and the content of P in roots; significantly (P<0.05) decreased the contents of P, K, Ca, Mg, and S in leaves; the contents of N, P, K, Ca, Mg, and S in stems; the content of N, Ca, and Mg in roots. Under AS treatment, the contents of P, K, Ca, Mg and S in leaves; the contents of N, P, Ca, Mg and S in stems; and the contents of N, P and S in roots significantly (P<0.05) decreased, while Mg content in roots significantly (P<0.05) increased over the CK treatment. Seven differential metabolic pathways were screened from cotton leaves and roots under the CS treatment; 16 and 29 differential metabolic pathways were screened from cotton leaves and roots under the SS treatment; and eight and 18 differential metabolic pathways were screened from cotton leaves and roots under the AS treatment. NaCl stress inhibited the transport of P, Ca, Mg, S, and N uptake in cotton but promoted the transport of N and K; NaCl stress had relatively little effect on metabolism, only the accumulation of amino acids and organic acids. Na2SO4 stress did not significantly inhibit the absorption and transport of N and K but promoted the absorption of Mg and S. However, it inhibited the absorption and transport of Ca and Mg in cotton. Na2SO4 stress had a significant impact on metabolism. The significant accumulation of S incotton promotes the metabolism of amino acids, and the enhancement of amino acid metabolism also indirectly promotes the intensity of other metabolic pathways, making cotton more tolerant to Na2SO4. Alkali (NaHCO3+Na2CO3) stress inhibited N and S uptake and P, K, Ca, Mg, and S transport but increased Mg uptake, which significantly changed the metabolism of organic acids in cotton, enhanced the metabolism of organic acids in roots, significantly accumulated organic acids, and significantly accumulated linoleic acid in leaves.
Time variation characteristics of agricultural green development indexes in Lishu County,Jilin Province
HOU Xiangcheng, LI Han, WANG Yin, FENG Guozhong, LIU Yajun, LI Xiaoyu, GAO Qiang
, Available online  , doi: 10.12357/cjea.20220189
Abstract(70) HTML (32) PDF(13)
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As an advanced agricultural production county in China, Lishu County in Jilin Province has always been at the forefront of green agricultural development; this study took it as a typical case. Through the established indicators system of Chinese agricultural green development, combined with the nutrient flows in food chain, environment and resources use (NUFER) model, it analyzed the characteristics and change rules of agricultural green development indicators in terms of social economy, food production, and ecological environment, from 1994 to 2019, in Lishu County. The driving and restricting factors of county agricultural green development in Jilin Province were further explored. The results showed that the overall level of agricultural green development in Lishu County has improved steadily from 1994 to 2019, with the number proportion of indicators of grade I and grade II decreasing from 47% to 23%, and the number proportion of indicators of grade III and grade IV increasing from 22% to 47%. In terms of social economy, the per capita comprehensive agricultural input and the per capita disposable income of rural residents have increased annually, and the per capita protein intake and the proportion of animal protein production have also improved, both reaching a grade IV level. Although the power of agricultural mechanization has shown an increasing trend, it is still at level I and needs to be improved. In terms of food production, the energy consumption per unit agricultural output value and the fertilizer phosphorus absorption utilization in farmland have been at level IV for many years; however, the comprehensive nitrogen use efficiency of livestock and poultry nitrogen has always been at a low level. The input of pesticides and fertilizer nitrogen reached level III in 2019; however, it did not increase continuously during the process, which was greatly affected by the years. In terms of the ecological environment, nitrogen emissions, nitrogen surplus, and environmental losses per unit cultivated land area due to nitrogen inputs all showed an improving trend from 1994 to 2019. However, the comprehensive utilization rate of livestock manure and the livestock and poultry carrying capacity per unit area was still at grade I, which meant that the development of the livestock industry still faces great challenges in Lishu County. Above all, the underutilization of resources, the environmental pollution, and ecological damage was caused by a single plantation structure, low yield of high-quality agricultural products, high input of pesticides and chemical fertilizers, and unstable numbers of livestock. It is therefore urgent to develop and utilize black land resources reasonably, to vigorously promote testing soil for formulated fertilization, improve conservational tillage and other excellent agricultural technologies, solve the contradiction between supply and demand of high-quality agricultural products, reduce damage to the ecological environment, and comprehensively promote the green development of agriculture in Jilin Province.
Effects of salt stress on physiological characteristics and yield of different salt-tolerant wheat varieties
TAO Rongrong, LU Yu, YU Qi, MA Quan, DING Yonggang, QIAN Jin, DING Jinfeng, LI Chunyan, ZHU Xinkai, GUO Wenshan, ZHU Min
, Available online  , doi: 10.12357/cjea.20220164
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Soil salinity is a global issue that affects wheat production, and it is of great interest to improve the production efficiency of wheat in saline fields. A comprehensive understanding of salt-tolerance mechanisms and the selection of reliable screening indices are crucial for breeding salt-tolerant wheat cultivars. Previous studies have reported the performance of wheat under salt stress and controlled experimental conditions, such as potted plants, seawater (saltwater) irrigation, hydroponics, and salt ponds, but could not simulate the actual production environment in the field and reflect the law of crop growth in a natural state. How salinity stress affects wheat yield, and the physiological indicators that contribute to yield formation under saline field conditions are not yet to be established. Five spring wheat varieties with significant differences in salt tolerance (salt-tolerant varieties: ‘NM21’ ‘YM20’ ‘YFM4’; salt-sensitive varieties: ‘YM23’ ‘AN1124’) screened in a previous experiment were grown at two sites with significantly different soil salinity, namely: non-saline (control, soil salinity before sowing was 0.770±0.062 g∙kg−1) and saline (soil salinity before sowing was 3.294±0.198 g∙kg−1) fields, in Dafeng, Jiangsu, China. The yield and its components, post-anthesis chlorophyll content, chlorophyll fluorescence Fv/Fm, malondialdehyde content, and proline content were measured. The results showed that the leaf area index, dry matter accumulation, and tillers number decreased significantly in saline field. Moreover, compared with the control, wheat yield in saline field decreased significantly and was only 26.2% of the control. The number of spikes, kernels per spike, and 1000-grain weight also decreased significantly. The number of spikes, which decreased by 60.7%, was the main constraint on yield production, followed by the 1000-grain weight, which also decreased. Salt stress also caused a significant decrease in chlorophyll relative content (SPAD value) and chlorophyll fluorescence Fv/Fm but significantly increased the malondialdehyde and proline contents; the range of change differed among varieties. Salt-tolerant varieties had a lower decrease in chlorophyll content and chlorophyll fluorescence Fv/Fm and a lower increase in malondialdehyde content but a higher increase in proline content, therefore, there was a lower decrease in yield. Correlation analysis was carried out for the physiological characteristics at the flowering stage, yield, and its constituent factors in wheat with different salt tolerances. The results showed that there was a significant positive correlation between chlorophyll fluorescence Fv/Fm and the number of spikes, 1000-grain weight, and yield, and SPAD value was positively correlated with dry matter accumulation. A significant positive correlation was observed between dry matter accumulation and the number of spikes, 1000-grain weight, and yield, indicating that salt stress inhibits photosynthesis in wheat by reducing chlorophyll content and chlorophyll fluorescence Fv/Fm, reducing the production of photosynthetic products, consequently resulting in a final yield reduction. Hence, in field identification, SPAD value and chlorophyll fluorescence Fv/Fm at the flowering stage can be used as fast and reliable indices for salt tolerance in wheat. Furthermore, ‘YM20’ had the lowest yield reduction rate and better overall performance, making it suitable for planting in Dafeng saline land.
Evaluation of the effect of future climatic change on Hebei cotton production and water consumption using multiple GCMs
WANG Keyu, YANG Yanmin, YANG Yonghui, LIU Deli, CHEN Li
, Available online  , doi: 10.12357/cjea.20230016
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Climatic model is the main source of uncertainty in climate change impact assessment. It can soundly decrease the uncertainty by using multiple climate models during assessment. In this study, the crop model APSIM-COTTON was carefully calibrated on the basis of two years of field experiments, and 22 GCM models (AR6) were used to driven crop models to evaluate the effects of climate change on cotton production and water consumption in Hebei Province. As the main growth indicators, leaf area index, plant height, square number, boll number and dry matter weight of each plant organ, were used to correct the variety parameters of APSIM-COTTON. The coefficient of determination was above 0.8 indicated the simulated and observed values were well fitted. The trend of climate change in this site was that the solar radiation intensity under SSP1-2.6, SSP2-4.5 and SSP5-8.5 was higher than the baseline and increased with the time, but it was lower than the baseline under SSP3-7.0; temperature tended to increase in all scenarios, and the amplitude increase with the increase of radiative forcing and time, the minimum temperature increased more than the maximum temperature; Annual rainfall increased over time in most scenarios. The response of cotton production and water consumption to future climate change was the comprehensive effect of CO2 concentration, solar radiation, temperature, rainfall and other climatic factors. The crop model simulation results showed that under all climate scenarios and all time periods in the future, the sowing date was advanced, and all development stages (emergence, squaring, flowering, and harvesting) were shorter than that the baseline period. In the 2090s, under the scenarios of SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5, the boll opening stage advanced 9.3 d, 12.0 d, 14.7 d and 16.0 d, respectively, while the harvest stage advanced 15.3 d, 21.0 d, 30.3 d and 35.2 d, respectively. The total ET in the year under all scenarios except SSP3-7.0 showed an increasing trend while the irrigation amount decreased. Under the SSP5-8.5 scenario, the annual ET in 2030s, 2050s, 2070s and 2090s increased by 6.5 mm, 7.8 mm, 14.3 mm and 32.7 mm compared with the baseline, respectively, while the irrigation amount decreased by 25.7 mm, 23.8 mm, 30.5 mm and 29.0 mm, respectively. In the future, the changes of cotton yield were not large in the scenarios of lower radiation focing and there was a decreasing trend with ages under high radiation forcing. Under the scenarios of SSP1-2.6 and SSP2-4.5, lint yield decreased about 61.5 kg∙hm−2 and 46.6 kg∙hm−2 in the 2090s. However, under the scenarios of SSP3-7.0 and SSP5-8.5, the reduction by 2090s reached 407.1 kg∙hm−2 and 432.5 kg∙hm−2. In this study, 22 GCM models were used to simulate the response of cotton growth and water consumption to climate change over 100 years in the 21st century, and the changing trends in different scenarios and different time periods were compared, which was expected to provide technical support for making adaption strategy to the climatic change. However, the uncertainty of evaluation the climatic effect on cotton production still exists in this study, and more site data should be considered in the calibration process and more crop simulation models with different mechanism should be compared in the evaluation in the future research.
Activation of phosphorus pools in red soil by maize and soybean intercropping and its response to phosphorus fertilizer
SU Lizhen, ZHAO Hongmin, HOU Xianfeng, CHEN Yuan, XIAO Jingxiu, ZHENG Yi, TANG Li
, Available online  , doi: 10.12357/cjea.20220345
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Phosphorus limits the growth of crops and is easily fixated to red soil; however, reasonable intercropping can promote phosphorus absorption and reduce phosphorus fixation. Studying the effects of maize and soybean intercropping on phosphorus transformation and mobilization in red soil in the southwestern drylands under different phosphorus application levels is of great significance. Based on four consecutive years of field positioning experiments, two planting modes — maize and soybean intercropping and maize monocropping — were set; four phosphorus application levels — no phosphate fertilizer (P0), 60 kg∙hm2 of P2O5 (P60), 90 kg∙hm2 of P2O5 (P90), and 120 kg∙hm2 of P2O5 (P120) — were also implemented. The effects of maize and soybean intercropping on phosphorus fractions in maize rhizosphere soil and the response of soil phosphorus to the phosphorus gradient were studied using modified Hedley phosphorus classification method. The contribution of different phosphorus fractions to the soil phosphorus activation coefficient (PAC) was investigated using a random forest model. Maize and soybean intercropping increased the available phosphorus content and phosphorus availability in red soil under phosphorus fertilization. Compared with maize monocropping, at P0 level, the available phosphorus content of the intercropping maize rhizosphere soil increased significantly by 70.4% (P<0.01). Maize and soybean intercropping greatly promoted the mobilization of phosphorus in red soil and conversion to the active phosphorus pool. At P0 and P90 levels, the soil PAC of intercropping was significantly increased by 87.4% (P<0.05) and 34.6% (P<0.01), respectively, compared with that of monocropping. Intercropping also increased the proportion of active phosphorus pool to total phosphorus by 15.1% averagely. Among them, the Resin-P content in the inorganic active phosphorus component at the P120 level was significantly increased by 53.7% (P<0.05), compared with in monocropping. Furthermore, the NaHCO3-Po (organic P extracted by sodium bicarbonate) content in the organic active phosphorus pool was significantly increased by 117.0% and 25.6%, at the P0 and P120 levels, respectively (P<0.05). Intercropping reduced the proportion of stable phosphorus pool in red soil by 1.1% of the total phosphorus. At P90 level, the content of Conc.HCl-Pi (inorganic P extracted from concentrated hydrochloric acid) in the stable phosphorus pool was significantly decreased by 40.2% (P<0.01) compared with maize monocropping. The random forest model showed that soil inorganic phosphorus was the main determinant of PAC, and the mean square error of PAC increased by 14.7% when the predicted value of water-soluble inorganic phosphorus (Resin-Pi) was removed. Maize and soybean intercropping significantly increased the available phosphorus content and PAC in maize rhizosphere soil, increased the proportion of active phosphorus pool and moderately stable phosphorus pool, and decreased the proportion of stable phosphorus pool in maize rhizosphere soil. The mobilization effect of maize and soybean intercropping on the phosphorus pool was significant at low and medium phosphorus levels, but not at high phosphorus level, while soil inorganic phosphorus components had a greater effect on PAC. The results showed that maize and soybean intercropping promoted the mobilization of phosphorus and the conversion of phosphorus to the active phosphorus pool in red soil, especially under conditions of medium and low phosphorus application. However, the effect of the intercropping of maize and soybean on the mobilization of phosphorus in red soil was not obvious under the condition of high phosphorus application.
Differences in soil microbial community and function between healthy and clubroot diseased plants of Chinese cabbage
ZHANG Zhihao, DENG Yishu, NIE Qiang, XIE Guoling, WU Liutong, DI Xueyan, SHI Hao, FU Kejian, ZHANG Jilai, LIN Chun, ZHANG Naiming, SU Youbo
, Available online  , doi: 10.12357/cjea.20220498
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Clubroot disease severely restricts the development of the cruciferous vegetables industry. Changes in soil microbial diversity and composition are not only closely related to cruciferous crop clubroot disease but are also crucial to soil health, sustainable development of agricultural production systems, and human health. Therefore, it is necessary to understand the differences in microbial community structure between clubroot and bulk soil. Illumina MiSeq high-throughput sequencing technology was used to sequence bacterial 16S rDNA and fungal ITS genes in the bulk soil of healthy (H) and clubroot infected (D) Chinese cabbage. The results were compared with relevant databases after quality control. The physical and chemical properties of the bulk soil were determined, and the differences in the microbial community structure and composition between samples were analyzed. The relationship between soil physical and chemical properties, soil microbial community, and clubroot disease was discussed, and the function of bacteria and fungi in the samples was predicted. The results showed that: 1) the evenness and diversity of the bacterial community in the bulk soil of healthy Chinese cabbage plants were higher than those in the bulk soil of healthy Chinese cabbage plants. The richness, evenness, and diversity of fungal communities in the bulk soil of Chinese cabbage plants with clubroot disease was higher than those in the bulk soil of healthy Chinese cabbage plants, indicating that clubroot disease greatly influenced the composition of the soil fungal community. 2) Actinobacteria, Proteobacteria, Firmicutes, Chloroflexi, Acidobacteria, and Gemmatimonadetes were the dominant phyla of bacteria in soil samples. Bacillus, Gaiella, Defluviicoccus, Clostridium, and Nocardioides were the dominant genera of bacteria in the soil samples. The dominant fungal phyla in the bulk soil were Ascomycota, Mortierellomycota, Basidiomycota, and Olpidiomycota. The main fungal genera identified were Gibberella, Mortierella, Thielavia, and Basipetospora. 3) Metabolism, environmental information processing, cellular processes, and organic systems are four types of bacterial functions with significant differences in bulk soil bacterial communities between healthy and diseased plants;the functional abundances of Gibberella, Thielavia, Kernia, and Fusarium in bulk soil fungal communities of diseased plants were higher than those of healthy plants. 4) Principal coordinate analysis showed that the bacterial and fungal community structures in the bulk soil of healthy and diseased plants were significantly different. Redundant analysis showed that pH, total nitrogen, available nitrogen, available potassium, and cation exchange capacity were the main factors influencing microbial community changes in bulk soil. This study provides a new basis for the study of rhizosphere microbial flora of cruciferous crops and provides the possibility for the study of the method of controlling clubroot by beneficial synthetic bacteria-mediated pathogenic bacteria, as well as a way to alleviate soil degradation and rebuild healthy soil.
Impact of domestication on the mechanism of millet and rhizosphere microorganism interactions
CUI Wenxiu, ZAI Xiaoyu, ZHAO Meicheng, ZHENG Chunyan, SONG Chunxu, ZHU Feng
, Available online  , doi: 10.12357/cjea.20220398
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Rhizosphere microorganisms can endow plants with new stress resistance, and variations in their community structure and ecological functions also reflect the adaptability of crops to environmental changes. Domestication affects the genetic diversity, physiological traits and metabolites of crops, which in turn affects the composition and function of rhizosphere microbial communities. So far, the research on crop domestication mainly focus on the correlation and influencing mechanism among plant genetic diversity, plant phenotypical and physiological characteristics. However, the role of microorganisms in the process of crop domestication and the exploration of the interactive mechanism with plants is still in its infancy. In this review, we firstly systematically summarized the current progress concerning the effects of domestication on the community construction of gramineous crops rhizosphere microorganisms. Thereafter, we focused on foxtail millet, an important C4 model plant originating in China, to discuss the effects of domestication on foxtail millet growth, physiological traits and how these changes may further affect the structural and functional properties of rhizosphere microbial communities. This work would contribute to provide theoretical guidance for the restoration of crop-microbe beneficial relationships in agricultural ecosystem.
Effects of earthworm mucus and straw charcoal on heavy metals during domestic sludge co-composting
HUAN Huihui, CHU Zhaoxia, WANG Xingming, FAN Tingyu, DONG Zhongbing, ZHEN Quan, ZHANG Jiamei, DAI Bibo
, Available online  , doi: 10.12357/cjea.20220253
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Heavy metals restrict the reuse of municipal sludge. To passivate the activity of heavy metals, reduce sludge toxicity, and create new value, 2 kg of sludge was composted with 40 mL earthworm mucus and 2%, 4%, 6%, and 8% straw charcoal, to investigate changes in the heavy metal mobility in sewage sludge. The results showed that, compared with the control sludge compost (CK), the pH increased by 1.42% (P<0.05) and the total nitrogen and total phosphorus decreased by 7.87% and 14.18%, respectively (P<0.05), after the addition of the mucus to the sludge. After adding both the mucus and straw charcoal to the sludge compost, the sludge gradually became alkaline; furthermore, its electrical conductivity value increased by 5.71%−9.58% (P<0.05), and organic matter content increased by 7.71%−24.60% (P<0.05). Although this enriched the content of soluble ions and available organic matter in the compost, the total nitrogen and potassium contents decreased by 19.10%–30.95% and 7.87%–14.31%, respectively, resulting in the loss of plant nutrients. By adding mucus to the sludge compost, different total heavy metal contents showed different declining trends; these included Cd, Cu, Ni, Zn, and Pb, which decreased by 3.59%, 7.03%, 10.93%, 8.39%, and 5.11% (P<0.05, except Ni), compared to the CK treatment group. The more active forms of Ni, Zn, and Pb were transformed into an unavailable residue form that was difficult to degrade; therefore, the proportion of residual forms increased by 61.81%, 120.19%, and 72.51%, respectively, compared with the CK treatment. When the mucus and different proportions of straw charcoal were added to the sludge, the total heavy metal contents decreased further. The total amount of Cd, Pb, Cu, Ni, and Zn decreased by 37.18%, 67.36%, 6.07%, 59.59%, and 31.82%, respectively, in the mucus plus 8% straw charcoal treatment group (P<0.05). The Ni and Pb associated with the carbonate, Pb associated with iron-manganese, and exchangeable Zn were gradually shifted to the residue form, so that the available contents of Ni, Pb, and Zn were significantly decreased by 28.08%, 42.00%, and 28.31%, respectively, in the mucus plus 8% straw charcoal treatment group, which passivated Ni, Zn, and Pb in the composted sludge. In contrast, organic form of Cu was converted into exchangeable and residual forms. Its available content was increased by 89.82 % (P<0.05) in the mucus plus 8% straw charcoal treatment group, and Cu was activated in the sludge during composting. In the analysis of the effect of mucus and different ratios of straw charcoal on the availability of heavy metals after composting, it was found that the correlation coefficients of straw charcoal addition with the available forms of heavy metals Cu, Zn, Pb, and Ni reached significant levels of 0.906, −0.909, −0.847, and −0.639 (P<0.05), respectively, while the correlation coefficients with Cd were lower. Finally, based on the principal component analysis and stepwise regression equations, mucus in combination with straw charcoal influenced the pH of the sludge compost, affecting the mobility of Ni, Zn, Pb, and Cu. Therefore, mucus plus 8% straw charcoal is an effective approach for treating the heavy metals in the sludge.
Impact of joining cooperatives on green production of family farms: an empirical analysis based on 422 provincial demonstration family farms
ZHANG Mingyue, ZHENG Jun, ZHAO Xiaoying
, Available online  , doi: 10.12357/cjea.20220817
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Green production is the only way for the sustainable development of agriculture. As the key subject of modern agriculture, it is of great theoretical value and practical significance to explore the effective ways of green production for family farms. We should study the value and the significance of the times. Based on the investigation data of 422 provincial demonstration family farms in Shandong Province, this paper empirically analyzes the influence of family farms joining cooperatives on their green production and its mechanism by using the ranking selection model and explanatory structure model. The conclusions were as follows: 1) quantitative analysis shows that the proportion of green production of family farms joining cooperatives is obviously higher than that of farms not joining cooperatives. 2) From the analysis of heterogeneity, it is found that the proportion of green production of farms that are leaders in cooperatives is obviously higher than that of farms that are ordinary members. Joining cooperatives is significant for the green production of grain and vegetable family farms, but not for other farms such as fruit and livestock breeding. Joining the cooperative has a significant impact on the green production of medium-sized (10-20 people) farms, but has no significant impact on the behavior of small-scale (less than 10 people) and large-scale (more than 20 people) farms. 3) After the family farm joined the cooperative, the three types of green production behaviors with the highest adoption rate are applying organic fertilizer (74.35%), water-saving irrigation (68.17%) and subsoiling (65.80%), and the three types of green production behaviors with the lowest adoption rate are ecological treatment of livestock and poultry breeding waste (26.84%), recycling pesticide waste (41.81%) and integration of water and fertilizer. 4) from the estimation results of regression equation, family farms can significantly increase the possibility of green production by joining cooperatives. Under the control of other variables, joining the cooperative has a significant positive impact on the green production of family farms at the level of 1%, with an impact coefficient of 0.554, and the promotion of water-saving irrigation, application of organic fertilizer and integration of water and fertilizer is more obvious. After taking other control variables into account, family farm management type, labor force, product quality certification, traceability of origin, awareness and willingness of green production all have influences on its green production. 5) From the analysis of the explanatory structure model, it is found that seven significant influencing factors not only play an independent role, but also are interrelated, forming a complete chain of influencing factors for family farms to participate in green production. Joining the cooperative as a deep-rooted factor directly affects the origin traceability and product quality certification of family farm products, and then affects the green production of family farms from the source along the positive conduction relationship of “family farm green production cognition→green production willingness→green production behavior”. Therefore, we should encourage and support family farms to join cooperatives, pay attention to the heterogeneity between farms, and promote green production of farms through training and supervision of cooperatives.
Accuracy evaluation and consistency analysis on multi-source remote sensing land cover data in the Yellow River Basin
WU Zongyang, CAI Zhuoya, GUO Ying, WANG Yanfang
, Available online  , doi: 10.12357/cjea.20220816
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With the development of multi-source remote sensing platforms and technologies, a variety of land cover datasets have been developed, which provide a wealth of data to support the understanding of global land cover conditions, land surface process model simulations and socio-economic development decisions. However, it is a challenge to select the appropriate data for different regions from these nationally or globally prepared land cover datasets. In this study, six land cover products in 2020 over the Yellow River basin, including CLCD_v01_2020, GLOBELAND30, GLC_FCS30_2020, LANDCOVER (300 m), MCD12Q1 (500 m) and CNLUCC1000 (1000 m), with resolutions from 30 m to 1000 m, were evaluated for regional scale accuracy and consistency analysis. Accuracy analyses were carried out on the six products based on 1540 samples from seven land cover types collected by Google Earth. The data with the highest overall accuracy (OA) was used as a reference for the area consistency analysis of the other five products. Category confusion analysis and confusion mapping analysis were also carried out on six types of data. It is hoped that this study will provide a scientific reference for users to select appropriate land cover data in the Yellow River Basin. The results show that the highest classification accuracy is CLCD_v01_2020 with an OA of 88.12%, followed by GLOBELAND30 (OA=85.32%), GLC_FCS30_2020 (OA=84.09%), LANDCOVER300 (OA=77.79%), MCD12Q1 (OA=73.38%) and CNLUCC1000 (OA=71.82%). The KAPPA coefficients of land cover products with a resolution of 30 m are all above 0.8, and the classification accuracy decreases as the spatial resolution decreases. The CLCD_v01_2020, with the highest OA, was used as the reference data, and the area correlations and confusion mapping were calculated separately for the remaining five validation product datasets. The relative proportions of different land cover categories are generally consistent across the six products, however there are still large differences between cropland and grassland. GLC_FCS30_2020 has the highest correlation with the reference data CLCD_v01_2020, with R2 of 0.9976. The category confusion analysis shows that the six data types are generally confused among cropland, forest and grassland. There is good consistency in the grasslands of eastern Qinghai of the upper reaches of the Yellow River, and in the cropland and construction land of the middle and lower reaches. The areas of poor consistency are mainly in the middle reaches of the Yellow River in northern Shaanxi, western Shanxi, mainly confused with grassland and forests. For primary classification of land cover data in the Yellow River Basin, it is recommended that CLCD_v01_2020 data should be selected for 30 m resolution and LANDCOVER300 for hundred-meter scale resolution data, while the secondary classification can be chosen according to the desired classification system.
Effects of optimized fertilization on yield, nutrient balance, and eco-environmental benefits in wheat-maize rotation system
YANG Huimin, YANG Yunma, HUANG Shaohui, YANG Wenfang, XING Suli, YANG Junfang, JIA Liangliang
, Available online  , doi: 10.12357/cjea.20220606
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The wheat-maize rotation system in the North China Plain is the main planting pattern that plays a key role in ensuring food security in China. An 8-year positioning experiment with a randomized block design was performed, comprising three treatments: no-fertilizer application control (CK), optimized fertilizer (OPT), and farmers’ practices (FP). The experiments analyzed the effects of OPT and FP on the yield, nutrient balance, greenhouse gas emissions, and economic benefits of the wheat-maize rotation system. The results showed that the yields of OPT increased by 4.3%, 5.3%, and 4.8% compared to FP in wheat, maize, and year-round rotation, respectively. Accordingly, the partial factor productivity of N increased by 39.1%, 31.7%, and 35.9%, respectively. The partial factor productivity of P increased by 39.1%, 40.4%, and 39.8%, respectively. The partial factor productivity of K was reduced by 47.8%, 47.3%, and 47.6%, respectively. The greenhouse gas emissions were reduced by 21.7%, 21.1%, and 21.4%, respectively. The greenhouse gas emission intensity was reduced by 27.0%, 27.5%, and 27.3%. Net profits increased by 11.2%, 11.4%, and 11.3%, respectively. Agronomy costs were reduced by 3.7%, 2.1%, and 3.1%, respectively. The environmental costs were reduced by 28.4%, 17.3%, and 22.1%, respectively. Compared with the FP treatment, the year-round OPT treatment reduced the surplus of nitrogen by decrement of 105 kg·hm−2, i.e., 46.3%. The surplus phosphorus was reduced by 48 kg·hm−2 i.e., 53.3%. The surplus of K of OPT and FP was 59 kg·hm−2 and −1 kg·hm−2, respectively. OPT met the requirements of crop growth better than FP. At the end of 8 years of wheat-maize rotation, the soil organic matter content in OPT treatment increased by 5.3% compared to that in FP. Compared to that of FP, available K increased and P reduced by 12.3% and 27.8%, respectively. In conclusion, compared with FP treatment, OPT treatment has the advantages of high yield, high profit, and environmental friendliness. Therefore, this study provides a scientific basis for the efficient and green product.
Spatiotemporal variation of dry-wet climate during wheat growing seasons from 1961 to 2020 in China
MA Xueqing, HE Huayun, ZHAO Jinyuan, FANG Tong, ZHANG Jianzhen, PAN Xuebiao, PAN Zhihua, WANG Jing, HU Qi
, Available online  , doi: 10.12357/cjea.20220371
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As the intensity of climate change increases, global warming continues to affect the hydrological cycle and precipitation characteristics. Changes occur at various locations owing to interregional differences in the intensity and distribution of precipitation and evapotranspiration. To determine the dry-wet climate distribution during the wheat growing season in wheat planting regions of China and the changes that have occurred over the past 60 years, we analyzed the temporal and spatial variation characteristics of China’s dry-wet climate over the inter-annual and inter-decadal periods from 1961 to 2020 (P1: 1961–1990; P2: 1991–2020). To explore how dry-wet climate changes, a series of dry-wet indices, such as effective precipitation, crop water demand, and water surplus and deficiency (difference between effective precipitation and crop water demand) were used. A Standardized Precipitation Evapotranspiration Index was used in this study for drought risk assessment in cropping regions. In this study, 524 meteorological stations with 60-year data records of China’s wheat planting regions were selected and divided into ten wheat planting regions. These regions are as follows. Spring wheat: Northeast China Spring Wheat Region, NES; Northern Inner Mongolia Spring Wheat Region, NIMS; Northwest China Spring Wheat Region, NWS; Northern Xinjiang Spring Wheat Region, NXJS. Winter wheat: Northern China Winter Wheat Region, NW; North China Plain Winter Wheat Region, NCW; Middle-Lower Reach of Yangtze River Winter Wheat Region, MLYRW; Southwest China Winter Wheat Region, SWS; South China Winter Wheat Region, SCW; Xinjiang Winter Wheat Region, XJW. The results showed that precipitation exceeded the crop water requirements during the wheat growing season in the SCW, SWW, and MLYRW regions over the past 60 years. Other regions experienced water deficits during wheat the growing season, with XJW (443 mm) and NXJS (495 mm) exhibiting the highest water deficit values. Estimates of effective precipitation, crop water demand, water surplus and deficit for the national wheat growing season ranged from 2.0–1320.0, 156.0–832.0, and 828.0–1081.0 mm, respectively. Both values showed a clear zonal distribution from southeast to northwest. In this study, drought frequency was calculated as 35.2%–59.6% for the national wheat growing season; it was more than 50.0% in the spring wheat regions and MLYRW regions. The frequencies of mild, moderate, and severe droughts during the wheat growing seasons were 18.7%–46.0%, 0–21.5%, and 1.7%–11.6%, respectively. The analysis showed that during the wheat growing season, effective precipitation volatility increased from 1961 to 2020, and crop water demand decreased and then increased again. The NCW and NW regions exhibited a drying climate, while the other regions showed a wetting climate trend. Further analysis revealed interregional differences in the climatic mechanisms of the wet-dry crisis in wheat planting regions. In NES, NIMS, NXJS, and XJW regions, effective precipitation increased and crop water demand decreased. Meanwhile, in MLYRW, effective precipitation and crop water demand increased, but the increase in precipitation was higher than that in crop water demand. Interdecadal variability in effective precipitation indicated a modest rising tendency; crop water demand declined in the P1 period and grew in the P2 period, whereas water surplus and deficit increased in the P1 period and decreased in the P2 period, respectively. This study makes an essential contribution to the research on the proper response of agriculture to climate change by showing the temporal and spatial variations of the dry-wet climate in China’s wheat regions.
Life cycle analysis of soybean production in typical counties of North China Plain
, Available online  , doi: 10.12357/cjea.20220841
Abstract(27) PDF(8)
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Synergy between ecological and economic benefits of grassland animal husbandry
, Available online  , doi: 10.12357/cjea.20220853
Abstract(102) PDF(9)
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Nitrogen acquirement strategy of different nitrogen forms in two pineapple cultivars
CHEN Xiaohui, XU Xiuyu, FU Liyong, PAN Yanju, FENG Ying, CAI Zhiquan
, Available online  , doi: 10.12357/cjea.20220857
Abstract(44) HTML (17) PDF(7)
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Pineapple [Ananas comosus (Linn.) Merr.] is the third largest tropical fruit in China, with the largest planting areas located in Xuwen county, Guangdong, China. As one of the largest required macronutrients, nitrogen is closely related to the yield of pineapple. However, the uptake preference of different nitrogen forms of the field-grown pineapple plants is not clear yet. In this work, the morphological, physiological and growth traits of the plants with different ages were measured in two field-grown pineapple cultivars (i.e., ‘Tainang 17’ and ‘Bali’) with different growth periods in April and September, respectively, in Xuwen County. In addition, nitrogen acquisition strategies of three different forms of nitrogen (i.e., ammonium nitrogen, nitrate nitrogen, and glycine) in pineapple roots were unraveled by using stable isotope 15N tracer technique. The results indicated that the growth period of ‘Tainang 17’ pineapple (16 months) was shorter than that of "Bali" (20 months). During the fruit harvest period in April, compared with ‘Bali’ pineapple (796 g fresh fruit weight per plant), ‘Tainang 17’ pineapple plants had lower yield (532 g fresh fruit weight per plant), root biomass, and P content; but had similar plant height, plant biomass per plant, leaf N and K contents and specific leaf area. As an indicator of long-term water-use efficiency, the δ13C value ranging from −15.16‰ to −13.28‰ was higher in leave of ‘Tainang 17’ pineapple than that in ‘Bali’ pineapple. Neither cultivar nor age greatly affected the leaf δ13C values. Either in April or September, there were significant differences in nitrogen uptake of different forms between the two pineapple cultivars. In general, the nitrogen uptake capacity of ‘Tainang 17’ pineapple was higher than that of "Bali" pineapple. The high acquirement capacity of nitrogen and water use efficiency of ‘Tainang 17’ pineapple attributed to promote photosynthesis and thus to maintain plant growth in a relative short life cycle. Both pineapple cultivars preferred to acquire ammonium nitrogen (36.8-64.6%), followed by glycine (23.2-47.1%); and the uptake rate of nitrate nitrogen was the lowest (9.1-31.5%). Compared with the plants in the fruit-harvesting stage, the nitrogen uptake rate of pineapple plants in the vegetative growth stage (5- to 8-month old) was higher. However, with the increase of plant age, the contribution rate of ammonium nitrogen increased, but that of glycine decreased gradually. Across different pineapple cultivars and plant ages, the rate of different forms of nitrogen uptake was not linearly correlated with soil nitrogen content or the measured plant traits. Overall, to the best of our knowledge, it is the first study to reveal that the roots of the field-grown pineapple plants have high ability to directly absorb organic nitrogen from the soils. The cultivar and plant growth stage of pineapples are important factors affecting the nitrogen acquisition strategy. But the linear relationships between the absorption rate of different nitrogen forms and soil nitrogen content or the measured plant traits are very weak. The above results contribute to nitrogen fertilizer management in the pineapple plantations.
Analysis of differential metabolites and metabolic pathways of mono- and inter- cropped wheat in response to the infection of Blumeria graminis f.sp. tritici
CHEN Sheng, WU Xinyu, HE Jianyang, ZHOU Dong, LIU Zhenyang, TANG Li, ZHENG Yi, XIAO Jingxiu
, Available online  , doi: 10.12357/cjea.20220808
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Wheat and faba bean cropping could alleviate the occurrence and severity of wheat powdery mildew, however, the physiological mechanism of intercropping improved wheat diseases resitance was still unclear. The purpose of this study was to understand the metabolic difference of mono- and inter- cropped wheat in response to the infection of Blumeria graminis f.sp. tritici and to reveal the physiological mechanism of intercropping forimproving wheat resistance to powdery mildew. In this study, three nitrogen (N) application levels were set: 75 mg·kg−1 (N1), 150 mg·kg−1 (N2), and 225 mg·kg−1 (N3). After inoculated with the B. graminis f.sp. tritici, the occurrence of powdery mildew in mono- and inter- cropped wheat was investigated, and the metabolomic analysis of mono- and inter- cropped wheat in response to the infection of B. graminis f.sp. tritici were analyzed with UPLC-MS/MS by widely targeted metabolomics method. The results showed that N levels and N levels×Planting patterns significantly affected the incidence and disease index of wheat powdery mildew. Under all three N levels, wheat intercropped with faba bean averagely reduced the incidence of wheat powdery mildew by 25.54%−38.81% and decreased the disease index by 18.54%−20.11% relative to mono- cropped wheat (MW), and the intercropping control effect under N1 level was better than N2 and N3 conditions. A total of 822 differential metabolites were detected in the mono- and inter-cropped wheat leaves, of which 69, 52 and 88 differential metabolites were found at N1, N2 and N3 levels, respectively. Wheat and faba bean intercropping regulated flavonoids, alkaloids, amino acids and derivatives, and phenolic acids in wheat leaves as compared to MW. The KEGG pathway enrichment analysis from differential metabolites showed that the differential metabolites were mainly enriched in the biosynthesis of amino acids, metabolic pathways, and the biosynthesis of secondary metabolites. Among them, metabolites with significant differences were enriched in the metabolic pathways at N1 and N2 levels, and the metabolites with significant differences were enriched in the amino acid biosynthesis under N stress conditions (N1 and N3). Further analysis of the metabolites from the top 10 up- and down-regulation found that, intercropping up-regulated glutathione (G-SH), L-tryptophan, L-asparagine, and L-glutamine in wheat leaves at N1 level relative to MW, and up-regulated L-asparagine, L-homomethionine, and L-tryptophan in IW leaves were obsereved at N3 level as compared to MW. In addition, a few other metabolites including alkaloids, phenolic acids, and organic acids in wheat leaves were also regulated by intercropping when compared to MW under N1 and N3 levels. In conclusion, the response of wheat to powdery mildew infection was regulated by N levels. The metabolites involving amino acids and their derivatives, alkaloids, phenolic acids, and organic acid in wheat leaves were regualated by intercropping during the infection of B. graminis f.sp. tritici and induced different physiological reaction, which may be one of the mechanisms of intercropping improved wheat powdery mildew resistance. Particularly, intercropping regulated amino acids and their derivatives under N stress were tightly related to wheat powdery mildew resistance. The present study identified the different responses of mono- and inter- cropped wheat to diseases infection via metabolism analysis, which is helpful to fully understanding crop diversity for the management of pests and diseases.
The configuration pathways of organic agriculture development in China:-A study based on fuzzy set qualitative comparative analysis
LU Yu, XIANG Ping’an
, Available online  , doi: 10.12357/cjea.20220265
Abstract(81) HTML (13) PDF(10)
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Organic agriculture is one of the most popular sustainable production methods at present. It is becoming an important way for the green development of agriculture in various countries. Testing the causally complex relationships between organic agriculture development and its multiple influencing factors and clarifying configurations and pathways for promoting organic agriculture development play an important role in achieve high-quality agricultural development. This paper advocated for an asymmetric configuration perspective that tests the causal complexity of high and not-high organic agriculture development. First, this paper used NCA method to explore the necessary conditions for organic agriculture development, and then employed fuzzy-set qualitative comparative analysis (QCA) to detect the impact of different configurations of multiple factors on organic agriculture development, and explores the synergy pathways with different configurations for organic agriculture development. Our main findings reveal that: first, any single explanatory attributing to organic agriculture development does not constitute the necessary condition. Instead of a one-size-fits-all approach, the main findings reveal four pathways with different configurations for high development of organic agriculture in China, that is, led and organized by government, market and organization driven, certification and organizations driven and certification driving resources. There are also three recipes for not high development of organic agriculture, all of which present the absent of organic certification and organizational conditions, which reveals that organic certification and organizational conditions play an important role in organic agriculture development. The inspiration for optimizing the development environment of organic agriculture is that although there are differences in market, ecological conditions, public policies and organizational conditions in various regions, this does not prevent these regions from promoting the development of organic agriculture through different configuration paths. The conclusions provide empirical evidence and theoretical reference for the government to formulate public policies to promote the organic agriculture development according to different situations. The contributions are as follows: First, This paper adopted NCA methods to examine whether any single factor constitutes a necessary condition for the development of organic agriculture in China, which not only advances the understanding of the prior research on correlational relationship between the influencing factors and organic agriculture development, but also reveals that the government support plays an important role in driving the development of organic agriculture in China; Second, Second, based on the configuration theory, the qualitative comparative analysis method QCA is used to explore the synergistic impact of multiple factors such as market environment, resource endowment, organizational conditions and policy systems on the development of organic agriculture. It is a useful supplement to the traditional empirical research and provides more detailed and rich empirical evidence for the complex causal relationship between the development of organic agriculture and its influencing factors. Third, This paper carried out a more systematic and specific analysis of the influencing factors and its driving path of organic agriculture development focused on provincial level, which enriches prior literature by offering a more fine-grained understanding of unbalanced development of organic agriculture in China. At last, this paper conducted the mixed study of NCA and QCA, which promotes the research on the necessary and sufficient causality between the influencing factors and organic agriculture development.
Effects of the combination of polystyrene nanoplastics and Pb on seed germination and seedling growth of spinach (Spinacia oleracea L.)
GUO Linlin, ZU Jingmei, WANG Jingjing, CHEN Bingxu
, Available online  , doi: 10.12357/cjea.20220721
Abstract(59) HTML (21) PDF(5)
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Microplastics (MPs), a new type of environmental pollutant, have attracted widespread concern for their negative effects on organisms and environment. However, there are few reports on the impacts of co-contamination of MPs and heavy metals on vegetable crops. To explore the effects of polystyrene nanoplastics (PSNPs), lead (Pb) and their co-contamination on seed germination and seedling growth of spinach, we investigated the germination rate, germination vigor, germination index, root length, shoot length, superoxide dismutase (SOD), peroxidase (POD) and soluble protein contents of spinach seeds and seedings respectively, which were exposed to control, PSNPs (200, 400, 800, 1600 mg·L−1) and Pb (5, 25, 50, 100 mg·L−1) and their combination (Pb5+PSNPs200, Pb5+PSNPs800, Pb50+PSNPs200, Pb50+PSNPs800). The results showed that single effects of PSNPs (≥400 mg·L−1) decreased the germination rate, germination vigor, germination index significantly, but there was no significant difference between 200 mg·L−1 PSNPs and control above those indicators. PSNPs at low concentration (200 mg·L−1) promoted the length of roots and shoots, but other concentrations (≥400 mg·L−1) of PSNPs had no significant impacts on roots and shoots. The activity of SOD was inhibited at high concentration (≥800 mg·L−1) of PSNPs, and the POD activity was induced when PSNPs≤800 mg·L−1, while POD was inhibited at the high concentration(1600 mg·L−1) of PSNPs. The soluble protein content in spinach seedlings of different concentrations of PSNPs increased, but the content was significantly higher than the control at 800 mg·L−1. Under Pb alone, the germination rate, germination vigor and germination index were reduced. Further, treatments with low concentration (5 mg·L−1) of Pb increased root and shoot length, while high concentrations (≥25 mg·L−1) reduced them. Moreover, inhibition of SOD and induction of POD were observed in the treatments of Pb. With the increase of Pb concentration, the soluble protein content of spinach seedlings decreased firstly at the low concentration (5 mg·L−1) and then increased. Compared with single Pb treatment, combined effects of PSNPs and Pb were generally antagonistic on the seed germination, for example, PSNPs weakened the promotion effects of low concentration(5 mg∙L−1) of Pb, and inhibited the growth of root and shoot of spinach seeds, while alleviated the inhibitory effects of high concentrations (50 mg∙L−1) of Pb on root and shoot growth. Low concentration (200 mg·L−1) of PSNPs and Pb showed synergistic effects in spinach seedings, such as enhanced the induction effects of Pb on POD activity. And the co-contamination of PSNPs in high concentration (800 mg·L−1) and Pb caused greater damage to seedings, for the activity of SOD and POD decreased significantly. The results showed that PSNPs could alleviate the inhibition effects of Pb on the germination of spinach seed. Low concentration of PSNPs (200 mg∙L−1) and Pb mainly showed synergistic effects, while high concentration of 800 mg∙L−1 PSNPs and Pb mainly showed antagonistic effects. This study demonstrates the co-contamination of PSNPs and Pb has significant toxicity on seed germination and seedling growth involved antioxidant system and soluble protein of spinach. In conclusion, coexisting PSNPs can change Pb bioavailability and plant performance. Our findings can help to evaluate the individual and comprehensive toxicity of microplastics and heavy metals to vegetable crops.
Soil AMF community structure and assembly mechanism of medical sativa field in Loess Plateau
GAO Rui, LUO Zhuzhu, HE Renyuan, NIU Yining, LIU Jiahe, CAI Liqun, HAI Long
, Available online  , doi: 10.12357/cjea.20220697
Abstract(42) HTML (13) PDF(6)
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Arbuscular mycorrhizal fungi (AMF) mediate interactions between plants and soils, which play crucial role in terrestrial symbiosis and one of the important components in soil microbial community. However, little is known about how soil AMF community varies in relation to soil properties loessial soil. Therefore, the present study investigated soil AMF diversity community structure and soil physicochemical properties in Medicago sativa field and Farmland in the semi-arid area of the Loess Plateau. Soil samples (0-20 cm) were taken from four treatments in June 2021:1) farmland (Zea mays) and Medicago sativa established in 2019(L2019), 2012(L2012), 2003(L2003). The Illumina MiSeq high-throughput sequencing and real-time fluorescent quantitative PCR technology were used to explore the structure and diversity of AMF communities under four treatments (Farmland, L2003, L2012 and L2019). The statistical methods (such as redundancy analysis and molecular ecological network analysis) were used to explore the relationship between soil physicochemical properties and AMF community. Zero model analysis were used to reveal the assembly process of soil AMF community. The results showed that long-term planting of alfalfa decreased soil total phosphorus and available phosphorus. The AMF gene abundance ranged from 1.02×104~copies∙g−1 to 1.50×104copies·g-1 in dry soil, being significantly higher in Medicago sativa established in 2003(L2003) than other treatment (P<0.05). The correlation analysis between the abundance of AMF gene and physicochemical factors showed that soil AMF gene abundance was positively correlated with Total nitrogen, and negatively correlated with total phosphorus content, and available phosphorus. A total of 1 class, 4 orders, 7 families, and 7 genera of AMF were identified. Glomus, Diversispora and Paraglomus were the common genera of Medicago sativa field and Farmland, the dominant genera of Medicago sativa field and Farmland were Glomus (65.15%−99.12%), It mainly contributed to the changes of soil AMF community structure in different treatment groups. Long-term cultivation of Medicago sativa propagated the rare microbial taxa, including Ambispora and Scutellospora, whereas Pacispora and Acaulospora were sterilized. Ambispora Were significantly higher in Medicago sativa established in 2019(L2019) than other treatment (P<0.05), The analysis of molecular ecological network showed that there were high-abundance genera (Glomus and Paraglomus) had a cooperative relationship in the ecological network, while the low-abundance genera (Pacispora and Acaulospora )had a competitive relationship in the ecological network. RDA analysis showed that there was no main environmental factor affecting the community structure of AMF. Null model was used to infer AMF community assembly processes. Farmland and Medicago sativa established in 2019 (L2019) communities mechanism were dominantly assembled with the deterministic process (66.67%), the heterogeneous selection contributed the most. Medicago sativa established in 2012 (L2012) and 2003 (L2003) communities mechanism were dominantly assembled with random process (100%), the undominated processes contributed the most in Medicago sativa established in 2012 (L2012) and the dispersal limitation contributed the most in Medicago sativa established in 2003 (L2003). Mantel test showed that there was no main driving environmental factor for AMF community assembly. Long-term Medicago sativa cultivation increased the random processes. It is beneficial to maintain the sustainability and stability of artificial grassland ecosystem function. In summary, long-term planting of Medicago sativa significantly affected the composition of AMF community in soil. This study provides basic data and theoretical basis for further study on the microbial mechanism of AMF in the Loess Plateau after years of Medicago sativa planting.
Estimation and spatio-temporal characteristics of winter wheat evapotranspiration in Henan Province based on NPP VIIRS data and SEBS model
LI Ying, CHEN Huailiang, LIANG Chen, SU Wei, HE Tian
, Available online  , doi: 10.12357/cjea.20220422
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Crop evapotranspiration (ET), a key variable in water and heat exchange in agricultural fields, is of great significance for understanding the dynamics of soil moisture changes in agricultural fields, monitoring and predicting crop drought conditions, and guiding scientific irrigation. This study combined the Surface Energy Balance System (SEBS) model to estimate ET of winter wheat in Henan Province during the critical growth period from 2016 to 2018 using the Visible Infrared Imaging Radiation Suite (VIIRS) data of the Sumi National Polar-orbiting Partnership (NPP) satellite. Experimental accuracies were compared between VIIRS ET and the other three ET products (estimated by Penman-Monteith formula, P-M ET; estimated with MODIS data, MODIS ET; and macro-weighing lysimeter-measured ET, Real ET), and the spatial and temporal variation characteristics of ET in winter wheat area of Henan Province were analyzed. The results showed that comparing the VIIRS ET estimated by our proposed method with the P-M ET, the total average relative deviation was 10.1%, and VIIRS ET exhibited high consistency with P-M ET. The measured ET of the macro-weighing lysimeter was used to verify accuracy, and the root mean square error (RMSE) of the calculated VIIRS ET was 0.203 mm·d–1. The verification results showed that the NPP VIIRS data are suitable for ET inversion. The determination coefficients of linear regression analysis of VIIRS ET and MODIS ET were 0.804, 0.734, and 0.802 for the April 17th in 2016, 2017 and 2018, respectively. The three years RMSE of VIIRS ET based on MODIS ET were 0.222 mm·d–1, 0.158 mm·d–1, and 0.211 mm·d–1, respectively. This shows that there is good consistency between VIIRS ET and MODIS ET, and that VIIRS data can be used as an effective supplement and substitute. The ET spatial distribution was generally higher in the middle and southeast and gradually decreased to the northwest and southwest. The spatial variation characteristics of ET corresponded well with that of irrigation conditions. According to the time characteristics of farmland ET during the key growth period of winter wheat in the study area, the average daily ET in the regeneration stage was the lowest, and then it increased gradually, reached a maximum at the heading stage, and began to decrease at the filling stage. The temporal and spatial characteristics of winter wheat field ET in Henan Province were closely related to the local field management mode. The accurate estimation of winter wheat field ET can provide a scientific basis for the design of irrigation management systems. This is important for the management, distribution, and efficient utilization of agricultural water resources.
Inhibiting effect of biological fumigation of mustard against Phytophthora nicotianae
SUN Di, HE Yilin, SHEN Danyu, DOU Daolong, TIAN Yue’e
, Available online  , doi: 10.12357/cjea.20220519
Abstract(71) HTML (67) PDF(5)
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Tobacco black shank caused by Phytophthora nicotianae is an important and destructive soil-borne disease affecting tobacco production in China. Biofumigation is a method to suppress or kill harmful organisms in the soil using volatile bioactive substances produced by plants, such as those of Cruciferae or Compositae, during decomposition. Brassica species are important biological fumigants. ‘Dilong 1’ (DL1) mustard was cultivated by our collaborator at Nanjing Agricultural University as Brassica juncea variety with high glucosinolates content, high biomass, high adaptability, and good fumigation effects. To explore a safe and environmentally friendly green method for the prevention and control of tobacco black shank disease, the inhibitory effect of fumigation with DL1 mustard on P. nicotianae was analyzed in this study through a series of petri dish inocubation experiments. The mycelial growth rate method was used to determine the effect of DL1 fumigation on mycelial growth of P. nicotiana. The fumigation effects on sporangium formation, zoospore release, spore germination, germ tube elongation, and oospore formation of P. nicotiana were also determined. The effects of DL1 fumigation on cell membrane permeability of P. nicotiana were determined by changes in electrical conductivity and malondialdehyde content. The change in the pathogenicity of P. nicotiana after fumigation was determined using the in vitro leaf method. The results showed that fumigation of fresh matter of DL1 mustard could significantly inhibit the mycelial growth of P. nicotiana. The EC50 (concentration for 50% of maximal effect) value was 0.36 g, EC75 (concentration for 75% of maximal effect) value was 0.499 g, and minimum inhibitory dose (MIC) was 0.500 g. The inhibitory effect was dose-dependent on the amount of fresh material in DL1 mustard. The amount of 0.3 g fresh DL1 mustard significantly inhibited sporangium formation and zoospore release of P. nicotiana, and the amount of 0.5 g could inhibit sporangium formation and zoospore release of P. nicotiana by 72.8% and 86.6%, respectively. When the amount of fresh DL1 mustard was increased to 0.7 g, sporangium formation of P. nicotiana was completely inhibited. The amount of 0.3 g and 0.4 g of fresh DL1 mustard could completely inhibit zoospore germination and germ tube elongation of P. nicotiana, respectively. Fumigation of DL1 could reduce the formation of oospores of P. nicotiana in a dose-dependent manner, and 0.7 g fresh DL1 mustard could completely inhibit the oospore formation of P. nicotianae. After fumigation, the permeability of the mycelium membrane of P. nicotianae increased, and membrane lipid peroxidation was induced. After 150 min of fumigation, the electrical conductivity of P. nicotiana was 2.2 times that of the control, and the malondialdehyde content was 8.0 times that of the control. The fumigation treatment weakened the pathogenicity of P. nicotianae, and the area of the disease spot decreased by 88.9% compared to that of the control. In this study, fumigation of DL1 mustard on the growth and development of P. nicotianae, physiological and biochemical characteristics, and pathogenicity changes indicated that it had a good inhibition and killing effect on P. nicotianae, and the fumigation effect had a dose-dependent effect on the amount of fresh DL1 mustard. This provided a theoretical basis for the use of DL1 mustard to control tobacco black shanks and other soil-borne diseases in production.
ENSO events impacts to Shandong apple production Ⅱ: changes of agricultural meteorological disasters under different ENSO scenarios and affected to apple yield
CUI Cheng, LIU Yuan, LIU Buchun, SUN Yankun, YANG Fan, ZHANG Xiaonan, LIU Shanshan, ZHU Yongchang, HE Jinna
, Available online  , doi: 10.12357/cjea.20220533
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Apple is one of the dominant fruits in Shandong province, which production is greatly affected by agricultural meteorological disasters. It is of great significance to explore the evolution characteristic of agrometeorological disasters and influence on local apple production under extreme climate events. In this study, based on the daily meteorological data, prefectural and municipal apple production statistical data and monthly ENSO events data from 1991 to 2019 in Shandong, using mathematical statistics analysis and ArcGIS spatial expression, we analyzed the study aims. The results showed that: 1) there are significant regional differences of agrometeorological disasters under different ENSO years during 1991 to 2019. During the period of fruit expansion from June to August, drought occurred frequently in El Nino years with 78 times and the highest frequency of drought was about 50%. In Neutral years, the flooding disaster is relatively serious, up to 60 times. Drought occurs frequently in areas with sufficient heat resources, such as Western and Central of Shandong. Rainfall and waterlogging disasters occur frequently in areas with abundant rainfall resources in Southern Shandong. In Eastern Shandong and Jiaodong Peninsula, the extreme low temperature disaster occurred frequently during apple flowering period from March to May. The number of low temperature days is about 7-9 d·a−1, which frequency is about 60%−100%. In Western Shandong Province and other places are the high incidence areas about high temperature heat disaster during apple fruit expansion period from June to August, with the occurrence days of 11-15 d·a−1. 2) Under different ESNO events, drought is positively correlated with El Nino years, while is negatively correlated in La Nina years. During apple growth period from March to October, there is a positive correlation between the Southern Oscillation Index (SOI) and rainfall in El Nino years, while it is a negative correlation between the SOI and rain waterlogging in La Nina and Neutral years. Low temperature disasters are negatively correlated with the SOI in El Nino years, while are positively correlated with SOI in La Nina years and Neutral years during apple flowering period from March to May. 3) During March to October, the drought in Jiaodong Peninsula has intensified leading to the increase of apple yield reduction rate in El Nino years; the impact on rain and waterlogging of apple yield and income is also aggravated in Neutral years. In La Nina years and Neutral years, drought in Western Shandong was positively correlated with apple yield reduction rate; while in neutral years, the rainfall in most areas of Shandong is positively related to the reduction rate of apple yield during apple expansion period from June to August. In El Nino years, the reduction rate of apple yield is less affected by extreme low temperature disasters, but more affected by high temperature heat damage. The number of days of low temperature increased in most areas of Shandong under La Nina and Neutral years, which led to the reduction rate of apple yield and risk increase. Beware of high temperature and drought in ENSO event, we should prevent the damage of low temperature, rain and waterlogging to apple yield and quality, and ensure the healthy and sustainable production of apple industry.
Effect of nitrogen fertilizer and conditioner on soil carbon and nitrogen content and yield of oat
SUO Wenkang, YANG Jinhan, HU Chenyang, FENG Shasha, TIAN Xiaoming
, Available online  , doi: 10.12357/cjea.20220553
Abstract(68) HTML (19) PDF(9)
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For the current situation of backward cultivation methods in northwest Hebei region that lead to oat's wide planting and thin crop, by introducing a new type of liquid conditioner, analyzing the changes in soil physical properties, organic carbon and total nitrogen and their components with the addition of conditioner, determining the influence mechanism of conditioner on soil quality, and combining the interaction between soil and crop, analyzing the change characteristics of nutrient uptake and yield of oat with different N dosage of added conditioner. To explore the driving mechanism of N reduction with conditioners on crop yield. In order to investigate the effect of conditioner on soil nutrients and yield of oat under N reduction, the new liquid conditioner developed by ourselves was used as the research object, and five treatments were set: no fertilizer (CK), 80% N fertilizer (N80), regular N application (N100), conditioner + 80% N fertilizer (PN80), and conditioner + regular N application (PN100). The results showed that the fertilizer treatments were different from the single fertilizer treatments in terms of the physical properties, the content of carbon and nitrogen components and the yield of oat. The results showed that the treatments with conditioner (PN80 and PN100) significantly increased soil water content, field water holding capacity, porosity and reduced soil bulk density compared with the treatments with single fertilizer application, and the nitrogen reduction of 20% (N80) significantly increased soil porosity and reduced soil bulk density compared with the conventional nitrogen application. The study on soil organic carbon, total nitrogen and its components showed that the 20% N reduction had different degrees of inhibition on organic carbon, total nitrogen and its components in different soil layers, and the addition of conditioner significantly increased organic carbon, total nitrogen, nitrate nitrogen and active organic carbon and microbial carbon in 0−60 cm soil layer and 20−60 cm soil layer compared with the treatment of N fertilizer alone. The effect of PN100 treatment was the most significant. The effect of different treatments on nutrients and yield of oat varied greatly, among which PN80 treatment had the most significant effect. Compared with N100, the total N, total P, total K contents and crop yield of oat in PN80 were significantly increased by 12.93%, 15.16%, 3.69% and 18.73%, respectively (P<0.05). Meanwhile, compared with N100, N80 significantly reduced nitrogen, phosphorus and potassium uptake in oat at 20% N reduction, but did not cause yield reduction in oat. In conclusion, compared with conventional fertilization, N80 (80% N fertilizer) with soil conditioner could improve soil properties, increase soil carbon content, reduce the risk of nitrate N leaching, and significantly increase the nutrient uptake and yield of oat plants. The effect of 80% N fertilizer + soil conditioner on the nutrient content and yield of oat was the most significant, while the treatment with 100% N fertilizer + soil conditioner was the most effective in terms of improving soil nutrient content. This is important to realize the green development of agriculture, reduce the environmental impact of fertilizer input, and improve the utilization rate of nitrogen fertilizer.
Change of soybean climatic suitability in Northeast China under climate change
HE Liang, MAO Liuxi
, Available online  , doi: 10.12357/cjea.20220574
Abstract(64) HTML (75) PDF(20)
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Northeast China was the major soybean production region, which was profoundly influenced by climate change. It was important to identify how did climate change influence agroclimatic resources, agro-meteorological disaster and soybean climatic suitability for soybean production and plant expanding. In this study, we evaluated the temporal and spatial change of the agroclimatic resources (accumulated temperature, growing season precipitation and sunshine hours in the rate of 80% climatic guarantee), agro-meteorological disasters (drought and frost days) and soybean climatic suitability by two climate reference periods, i.e. 1991−2020 and 1981−2010. Finally, contribution rates of accumulated temperature, precipitation and sunshine hours to the soybean suitability change were calculated by a statistical method. We found that: 1) ≥10 ℃ thermal time during soybean growing season have increased by 26−65 ℃·d in the east of Inner Mongolia autonomous region, southwest and northeast of Heilongjiang province and Midwest of Jilin province, and increased by 66−182 ℃·d in local regions. Additionally, ≥10 ℃ thermal time during soybean growing season had an increased trend from 1981 to 2020 in Northeast China. Moreover, the change of precipitation and sunshine hours during soybean growing season had the characteristics of spatial differentiation. 2) The frost days during soybean growing season has decreased in the major region of Northeast China by 1 to 3 days, and by 4 to 6 days in some local areas. The drought days have declined in Heilongjiang province and Northwest of Jilin province by 1 to 4 days, while increased in Mideast of Jinlin and Liaoning province by 1 to 6 days. 3) the climatic suitability of soybean planting has improved in east of Inner Mongolia autonomous region, west of Heilongjiang and Jinlin, and Liaoning province, while have dropped in middle and east of Heilongjiang, Middle and northeast of Jinlin province. 4) the change of sunshine hours was the major factor for the soybean climatic suitability. Secondary factor was the thermal time, while precipitation had the least contribution. The results indicate that the climatic conditions of soybean in 1991-2020 in Northeast China had become better than in 1981−2010. The farmers in the Northeast China would adopt sowing date and soybean cultivar to fully utilize the temperature resource. However, blindly growing soybean across the accumulated temperate zone was not encouraged from the increased extent of thermal time.
Determination of water price and estimation of water savings and emission reduction in groundwater irrigation areas-A case study of Nanpi County, Hebei Province
WANG Xiqin, JIANG Zhiqiang, ZHANG Xinyue
, Available online  , doi: 10.12357/cjea.20220579
Abstract(97) HTML (38) PDF(2)
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A comprehensive reform of agricultural water prices is required to study and propose a reasonable water price adjustment scheme. The method regarding the determination of water price and the estimation of water savings and pollutant emission reduction in groundwater irrigation areas were proposed, and the current irrigation water use and current water price were calculated by using the method of “converting electricity into the water.” The double logarithm model was used to establish the price elasticity function of irrigation water demand. The ideal water price was calculated using the residual value method, and the pollutant emission reduction from water savings was calculated using the farmland pollution logistics loss model. Taking Nanpi County of Hebei Province as an example, the results showed that the current water prices of wheat and corn are 0.44 ¥∙m−3 and 0.48 ¥∙m−3, respectively. The water price elasticity coefficients of wheat and corn are −0.47 and −0.71, respectively. The actual water prices of wheat and corn corresponding to the irrigation quota are 0.52 ¥∙m−3 and 0.77 ¥∙m−3, respectively, and the ideal water prices are 0.84 ¥∙m−3 and 1.01 ¥∙m−3, respectively. As per the recommended scheme, the theoretical water price accounts for less than 15% of the total cost, the increased range for water price of wheat and corn is 0.08 ¥∙m−3 and 0.29 ¥∙m−3, respectively; and the water-saving potential is 235.05 m3∙hm−2, 682.80 m3∙hm−2. The nutrient emission reduction of ammonia nitrogen, total nitrogen, and total phosphorus are 5.2−19.2 g∙hm−2, 52.7−195.4 g∙hm−2, and 4.6−16.9 g∙hm−2 for maize; and 18.5−27.6 g∙hm−2, 189.1−281.2 g∙hm−2, and 16.3−24.3 g∙hm−2 for corn, respectively. As the comprehensive reform of agricultural water prices is a systematic project, it needs the support of relevant supporting policies. This study suggests the adoption of water-saving technology, land transfer, large-scale operation, and irrigation quota management systems to promote comprehensive reform of agricultural water prices through relevant incentive policies.
A Study on the research hotspots and emerging trends of international agroecology based on WOS
MU Junfang, ZHANG Lixin, YANG Guang
, Available online  , doi: 10.12357/cjea.20220578
Abstract(71) HTML (19) PDF(12)
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In recent years, with continuous changes of the ecological environment, there is a general public perception that promoting the coordinated and sustainable agriculture is much higher than the development of extensive, industrial as well as single-oriented agriculture. Agroecology, as an interdisciplinary science of ecology and agricultural science, provides a channel to optimize conventional farming systems and ecological agriculture practices, thus becoming thriving research hotspots in the present day. Therefore, clarifying the research hotspots and emerging trends of international agroecology research helps explain its development and prospect, while there is little in-depth research on this topic. Thus, this study employs the visual analysis software CiteSpace to conduct a bibliometric analysis of the relevant literature on the international agroecology research in Web of Science from 2012 to 2021. According to the study, three points stand out. The first point is concerned with research hotspots of studies on international agroecology. Specifically, through the analysis of 19 keyword clusters, it shows that the research hotspots focus more on the agro-ecosystem’s overall performance and evaluation, for example, the investigation on irreversible influences of climate change, the optimization of climate resilient system along with the improvement of field. Besides, the fundamental and scientific research of ecological agriculture practice gains extensive scholarly focus, in particular, the study on agricultural intensification, integrated weed management, soil organic matter and plant function trait etc. Additionally, the social movement of ecological agriculture with its social influence on food security and food sovereignty have been widely investigated. The second point centers on the basic knowledge of studies on international agroecology. Via a detailed account of highly cited reference and references co-citation clustering network, the knowledge base reflects that international agroecology scholars have done many basic and innovative studies in this field. Notably, the related knowledge base dwells on the ecological transformation of agriculture and the industrial form of ecological agriculture, the social movement of ecological agriculture, as well as how to adjust the ecological factors embedded in agricultural ecosystems (e.g. crop diversification, diverse cropping systems and plant patterns) to construct a sustainable agro-ecosystem. The third point relates to emerging trends of studies on international agroecology. Based on burst words and references with subsequent citation burst, emerging trends highlight more on agrobiodiversity, biodiversity conservation, landscape ecological security pattern, production system and pesticide pollution within natural sciences. Meantime, it also involves the research of social management field, specifically, the cultivation of knowledgeable farmers, agricultural education and the connection between indigenous knowledge and modern agro-ecological practices on the basis of participatory action research. As for the significance of the study, this paper contributes to mirroring the research hotspots and emerging trends of international agroecology, thus giving readers a guidance to probe into how the research foci, knowledge base along with research front of international agroecology research change. Moreover, rooted in the national conditions, the future development of domestic agroecology can strengthen international exchanges and cooperation, follow international hot research topics; meantime, future research can keep in step with the national development strategy and boost the advancement of new agricultural technology, thus enhancing the diversity and sustainability of agro-ecosystem.
Influence pathways and effects of agricultural mechanization on the application of chemical fertilizers
WAN Lingxiao, YANG Guo
, Available online  , doi: 10.12357/cjea.20220686
Abstract(35) HTML (20) PDF(9)
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Achieving green agricultural production depends on the change of production methods of smallholder farmers. Compared with the previous studies which focused on manual fertilizer application, this study focused on the effect of fertilizer application and fertilizer uniformity through the combination of fertilizer application with machinery after farmers used machinery. Using data from the 2017 China Rural Household Panel Survey (CRHPS), the impact of agricultural mechanization on fertilizer use in wheat is explored through OLS as well as treatment effects models, with attention to differences in fertilizer application across sources of machinery use. The results show that the use of machinery do not reduce fertilizer use in wheat, but is able to reduce inter-farmer fertilizer application differences. Only machine sowing decreases fertilizer application and unevenness among segments, mostly because wheat has a greater fertilizer application rate in the segment that involved machine sowing. After separating the various sources of farm machinery use, it is discovered that using machinery service rather than buying machinery equipment reduced the amount of fertilizer applied per hectare by 150.45 kg and increased fertilizer uniformity. In instance, compared to purchasing machine seeding, the purchase of machine seeding service lowered the fertilizer application by 213.45 kg per hectare and increased the fertilizer application uniformity by 0.32 units per hectare. Additionally, farmers can cut their fertilizer input by 283.95 Yuan per hectare by adopting machine sowing, and they can cut it by purchasing machinery services. This suggests that agricultural mechanization can achieve fertilizer reduction and reduce fertilizer application inequality among farmers, mainly through outsourcing. The findings of this paper can help expand the understanding of the relationship between agricultural mechanization and modern agriculture, and can also provide strong support for the green transformation and sustainable development of agriculture in China.
, Available online  
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Effects of different precipitation years on soil nitrate distribution, leaching loss and nitrogen uptake and utilization under drip irrigation of maize
ZHAI Yongquan, MA Kun, JIA Biao, WEI Xue, YUN Binyuan, MA Jianzhen, ZHANG Hao, JI Li, LI Jiaorun
, Available online  , doi: 10.12357/cjea.20220517
Abstract(52) HTML (48) PDF(8)
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In order to improve crop yield, excessive nitrogen application in agricultural production has become increasingly serious in recent years. Excessive nitrogen application leads to increasing accumulation of soil nitrate nitrogen and water pollution, and nitrogen leaching loss varies among different precipitation years. It is of great significance to clarify the scientific fertilization model among different precipitation year types under drip irrigation in Ningxia to alleviate the problems of resource waste, water quality decline of Yellow River and groundwater pollution caused by unreasonable nitrogen application. In this study, a 3-years nitrogen gradient experiment was carried out in Pingjipu Farm, Ningxia Hui Autonomous Region, with five nitrogen application treatments of 360 kg∙hm−2 (N4), 270 kg∙hm−2 (N3), 180 kg∙hm−2 (N2), 90 kg∙hm−2 (N1), and 0 kg∙hm−2 (N0), to analyze the effects of different nitrogen fertilization treatments on soil nitrate nitrogen residue and leaching amount, as well as on nitrogen absorption, utilization and yield of corn under drip irrigation in rainy and dry years. The results showed that the peak value of soil nitrate nitrogen content was closely related to precipitation, the peak value of nitrate nitrogen residue was at 40-60 cm soil layer in Rainy years (2018 year), and at 20-40 cm soil layer in dry years (2019 year and 2020 year). Different precipitation years soil nitrate nitrogen residue and leaching increased with the increase of nitrogen application, and reached the maximum value under N4 treatment. Precipitation significantly affected nitrate leaching, and in rainy years the nitrate nitrogen leaching loss caused by factors accounted for 50.62% of the total leaching loss, and the dry year accounted for 34.82% of the total leaching loss. The regression analysis results showed that maize yield increased firstly and then decreased with the appropriate amount in different precipitation years. And the maximum yield was found under 270 kg∙hm−2 (N3) in different precipitation years, and the yield and nitrogen uptake under N3 treatment have no difference with 360 kg∙hm−2 (N4). In Rainy and dry years, compared with N4, the utilization rate, agronomic utilization rate of nitrogen fertilizer and partial nitrogen fertilizer productivity increased by 11.38%, 6.16 kg∙kg−1, 13.85 kg∙kg−1 and 12.10%, 5.06 kg∙kg−1, 15.00 kg∙kg−1. To sum up, Considering the distribution characteristics of nitrate in 0-100 cm soil layer, the amount of nitrate leaching, and the yield and nitrogen uptake and utilization under nitrogen application in different precipitation years, when the nitrogen application rate was 270 kg∙hm−2, the yield and nitrogen uptake and utilization of maize in rainy and dry years were maintained at a high level, and the amount of nitrate leaching was also within an acceptable range. It is recommended that 270 kg∙hm−2 is the appropriate nitrogen application rate for maize under different precipitation patterns in Ningxia Yellow River irrigation area. The maximum threshold of nitrogen application rate in rainy year is 275.59 kg∙hm−2, and the maximum threshold of nitrogen application rate in dry year is 320.20 kg∙hm−2. The results of this study can provide a theoretical basis for the decision of scientific nitrogen application among different precipitation year types of drip irrigation maize in Ningxia Hui Autonomous Region and the green and sustainable development of agriculture.
The impact of agricultural socialized services on the reduction of fertilizer-Double inspection based on panel data of 31 provinces in China
GAO Enkai, ZHU Jianjun, ZHENG Jun
, Available online  , doi: 10.12357/cjea.20220637
Abstract(94) HTML (90) PDF(10)
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In the face of the realistic dilemma that the traditional small farmer management cannot meet the sustainable development of agriculture, the reduction of chemical fertilizer is an important measure for China’s agriculture to move towards high-quality development, and it is also the key to the development of green agriculture. Based on the theory of professional division of labor,a theoretical model of “service outsourcing - division of labor economy - reduction of chemical fertilizer” is constructed. And using the statistical yearbook data from 2010 to 2020, this paper empirically analyzes the mechanism of agricultural socialized services on reduction of chemical fertilizer by using intermediary adjustment model and instrumental variable model. The study found that agricultural socialized services have a significant negative impact on the total use of chemical fertilizer and the use of unit area, That is, for every 100 million yuan increase in the output value of agricultural socialized services, the total chemical fertilizer use of 55500 tons and the use of 44300 tons per unit area can be reduced respectively. The robustness test of tool variables also confirms the positive effect of agricultural socialized services on the reduction of chemical fertilizer. At the same time, resource allocation, technological progress and disaster area have a negative impact on the use of chemical fertilizers of 0.094, 0.192 and 0.280 respectively, while deepening the division of labor, government leadership and grain output have a positive role in promoting the total use of chemical fertilizers, with the impact effects of 0.063/0.023 and 0.266 respectively From the perspective of mechanism, agricultural socialized service reduces the application of chemical fertilizer through resource allocation and scientific and technological progress. The deepening of labor division has a 0.039 promotion effect on this path, and the government led negative impact of 0.271 and inhibition of 0.017 on the reduction of chemical fertilizer and this path, respectively. Further research found that there are differences between agricultural service scale, agricultural development degree and geographical location in the impact of agricultural socialized services reducing chemical fertilizer. Provinces with small service scale have a greater impact on the reduction of chemical fertilizer. Agricultural provinces have a higher impact on the reduction of chemical fertilizer than non-agricultural provinces on the premise of more complete agricultural infrastructure and more mature industrial chain. The agricultural socialized services in the central and western regions have no significant impact on the use of chemical fertilizer. Among them, the lack of supervision system and the lack of deepening division of labor are the main problems faced by China's agricultural socialized services and they are also important factors that hinder the realization of fertilizer reduction. Therefore, we should continue to play the positive role of agricultural socialized services in reducing the amount of fertilizer, and expand the market demand for socialized services and green agricultural products; We will improve the deepening and supervision system of socialized service division, establish a sound service outsourcing and green production standard system, and strengthen risk management and control, promote rational allocation of resources, and realize income increase and production increase of farmers.
Responses of yield traits and grain filling characteristics of maize monoculture to sowing dates and their relationships with meteorological factors
CAO Caiyun, DANG Hongkai, LI Jia, LIU Xuetong, MA Junyong, LI Kejiang, ZHENG Chunlian
, Available online  , doi: 10.12357/cjea.20220592
Abstract(62) HTML (50) PDF(10)
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This paper discussed the influence mechanism of sowing dates on maize yield. Under the condition of limited water irrigation, the effects of different sowing dates on yield, yield traits and grain filling characteristics of maize monoculture and the correlation between meteorological factors at different sowing dates and yield, yield traits and grain filling parameters were studied, which provided data support for high yield and high efficiency production in low plain areas. ‘Xianyu 335’ and ‘Zhengdan 958’ were used in the experiment. Five sowing dates were set: May 5 (SD1), May 20 (SD2), June 5 (SD3), June 20 (SD4) and June 30 (SD5). The results showed that: 1) the yield had significant effect by sowing dates and was affected by variety and climate year. The grain yield increased initially and followed by decrease subsequent decrease with the extension of sowing dates. The two-year-average yield of SD1 was the lowest, and that of SD4 was the highest. The yield difference between SD3 and SD4 was not significant. The high yield of SD4 was mainly due to the high grain number per spike and 100-grain weight. 2) Path analysis showed that the contribution of yield factors to yield affected each other, and the most direct effect on yield was 100-grain weight. 3) The variation characteristics of grain weight described by Logistic Model, the determination coefficient R2 was above 0.98, and the difference was significance at P<0.01.The grain weight is determined by the product of the average grain-filling rate (V) and the grain filling duration (D), and D has the largest direct contribution to the grain weight. 4) From the effect of meteorological factors on yield and yield traits, the higher the daily average temperature from sowing to silking, and the larger the daily temperature difference (TRAvfm) from silking to maturity, the higher the yield. The more days ≥35 ℃ (D1fa) after silking 10 days, the higher the daily average temperature (TAvfm) from silking to maturity, the lower the yield and 100-grain weight. The TAvfm had the largest direct contribution to yield and 100-grain weight, and the effects of various meteorological factors on yield and grain weight were mutually affected. The main reason for the lower grain weight of SD1 was that the accumulated temperature ≥10 ℃ during the whole growth period and the accumulated temperature from sowing to silking ≥10 ℃ were higher, TAvfm was higher, TRAvfm was smaller, and the days of D1fa were more, and D was shorter. SD3 and SD4 had larger TRAvfm, higher V and D, and higher grain weight. Although the sowing date of SD5 was relatively later, the lower TAvfm resulted in the decrease of the accumulated temperature from silking to maturity, and filling stage was shortened, thereby reducing the final grain weight. 5) In terms of varieties, the main reasons for the higher yield of ‘Xianyu 335’ compared with ‘Zhengdan 958’ were the higher grain number per spike and 100-grain weight, and the V and the product V and D of ‘Xianyu 335’ were 0.19 mg·grain−1·d−1 and 0.73 mg·grain−1·d−1 higher than those of ‘Zhengdan 958’, respectively. This showed that selecting varieties with high yield potential and high filling rate, sowing from early June to middle and late June could optimize meteorological factors during growth period, thereby increasing grain weight and yield.
Accelerating carbon conversion in garden waste composting with food waste-expanding microbial inoculants
ZHANG Lu, WANG Hongge, WANG Weishuai, WANG Xuan, LI Jing, LI Lin, GUO Weiting, LIU Shuang, WANG Hong, LU Yunli, MA Lin
, Available online  , doi: 10.12357/cjea.20220744
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The expansion of urbanization has resulted in the generation of a large amount of garden waste (0.4 million tons), while traditional treatment methods (incineration, landfill) tend to cause serious environmental pollution and waste of resources. Composting is an effective way to realize the resource utilization of garden waste. However, the high lignocellulose content restricts the resource utilization of garden waste. Accelerating the degradation of lignocellulose in the composting process is of great significance to achieve effective resource utilisation of garden waste. Inoculation with exogenous microorganisms is considered an environmentally friendly and cost-effective way to accelerate lignocellulose degradation. In order to further reduce the cost of inoculum production and improve the inoculation efficiency. In this study, food residues (apple dregs, bean dregs) were used instead of conventional carbon and nitrogen sources (glucose, peptone) to propagate lignocellulose-degrading bacteria, and the number of viable bacteria in the multiplication product reached 3.7×1010 cfu∙ml−1, which increased by 46.2% compared with the traditional industrial medium. The effects of different inoculum amounts (0, 2%, 4% and 8%, dry weight) on carbon conversion during garden waste composting were also discussed. The results showed that the inoculation treatment significantly increased the degradation of lignocellulose (P<0.05). The total lignocellulose degradation rates of the 2%, 4%, and 8% inoculation treatments (2%, 4%, and 8% IM) were increased by 6.3, 9.2, and 23.0%, respectively, compared with CK. The dynamic changes of humus precursors (reducing sugars andpolyphenols) and humus components were further analyzed. The 8%IM treatment accelerated the complete mineralization of carbon, resulting in the complete degradation of humus precursors (polyphenols, reducing sugars) into CO2, which inhibited the humification. Compared to CK, 2%IM and 4%IM, the cumulative CO2 emissions of 8%IM increased by 21.9%, 22.3% and 26.0% respectively. The 4% IM treatment accelerated the degradation of lignocellulose while promoting the synthesis of humic acid (HA). The final HA content reached 91.3g∙kg−1, which was 24.9, 10.7, and 35.8% higher than that of CK, 2%IM, and 8%IM treatments, respectively. These results indicate that appropriate inoculation is beneficial to the directional transformation of lignocellulose to humic acid, whereas excessive inoculation would lead to an excessive loss of organic matter due to the high metabolic activity of microorganisms, and the degradation efficiency of lignocellulose is lower when inoculated with a small amount.This view was further proved by partial least square path analysis model in this study. The conversion of lignocellulose to DOC increased with the increase of inoculation amount (R of CK, 2%IM, 4%IM and 8%IM were 0.59, 0.70, 0.75 and 0.85, respectively), while the R value of 4%IM from DOC to HA was −0.85, which was higher than 2%IM (−0.76) and 8%IM (−0.34). Therefore, the growth and propagation of lignocellulose-degrading bacteria can be completely realized by using food residues as culture substrate. Meanwhile, 4% inoculation amount is more conducive to the humification of garden waste compost and the preservation of carbon. This study provides reference for garden waste composting inoculation process and theoretical basis for multi-source waste efficient collaborative treatment.
Growth and photosynthetic characteristics study of different heat-sensitivity potato genotypes during tuberization stage at high-temperature stress
ZHOU Jinhua, LI Youhan, ZHANG Xing, HU Hairong, GUO Huachun
, Available online  , doi: 10.12357/cjea.20220658
Abstract(77) HTML (54) PDF(4)
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Potato (Solanum tuberosum L.) is an important grain and vegetable crop, global warming affects its growth and production because of its high-temperature-sensitive characteristic. Investigating the physiological difference between heat tolerant and heat sensitive resources can help to rationalive the mechanism of high-temperature resistance in potato. The parameters related to morphology and photosynthesis of the heat-tolerant line ‘Dian 187’ (D187) and the heat sensitive cultivar ‘Qingshu 9’ (QS9) were measured and analyzed after two weeks of high temperature stress at 30 ℃. In high temperature stress, the plant height and internode length were increased, and the leaves were upright, the length and area of leaves were reduced, and the plant architecture was more compact; the change extent of the leaves number and bend angle in D187 was greater than in QS9, indicating that potato morphology affected the net photosynthetic rate, water use efficiency, maximum net photosynthetic rate, apparent quantum yield, carboxylation efficiency, maximum carboxylation rate, maximum electron transport rate in QS9 were lower than in D187 under high temperature stress. Furthermore, D187 had lower light compensation point and dark respiration rate than the heat sensitive one (QS9), As a result of strong adaptability, the amount of indexes exceeded over 0.5 in D187 were predominant plasticity indexes of morphology and photosynthesis and the indexes mean is 0.448 in D187 higher than 0.418 in QS9. Furthermore, the ability to absorb CO2 and low concentration CO2 utilization was weakened along with the acceleration of water loss and declination of water use efficiency in potato plant. As a consequence, the respiratory consumption was increased, the regeneration ability of ribulose 1,5-diphosphate (RuBP) and the chlorophyll fluorescence parameters were reduced in the dark. In contrast, the chlorophyll fluorescence parameters were increased under light and the utilization ability of limited light was also enhanced. Difference in morphology and photosynthesis self-adaptation abilities is the main reason for difference in high-temperature resistance between heat tolerant and heat sensitive resources, these results will help clarify the mechanism of high-temperature adaptability in potato plant, and provide references basic for the selection of high-temperature-resistant cultivars and innovation in cultivation techniques.
Characteristics of structure and abundance of soil nitrogen-fixing bacterial community in alfalfa with different growing ages in the loess plateau
WANG Xiaofei, LUO Zhuzhu, LI Lingling, NIU Yining, SUN Pengzhou, HAI Long, LI Linzhi
, Available online  , doi: 10.12357/cjea.20220505
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Biological nitrogen fixation is the major nitrogen source in alfalfa field, and nitrogen supply and soil fertility can be largely affected by the composition and quantity of the nitrogen-fixing bacterial community. In this study, a field experiment was conducted to explore soil nitrogen-fixing microbial community structure and abundance characteristics in loessal soil with alfalfa growing ages (2019, 2012, 2003), taking farmland as the control. The fluorogenic quantitative real-time PCR technique was adopted in the experiment using the high-throughput sequencing platform Illumina Miseq to target the nifH gene. We analyzed the ecological status of abundant and rare nitrogen-fixing microorganisms through co-occurrence networks, and identified the dominant factors affecting the community structure of nitrogen-fixing microorganisms by coupling soil physical and chemical properties. The results showed that long-term planting of alfalfa increased soil organic carbon, total nitrogen and soluble carbon content. The nifH gene abundance ranged from 2.97×106 copies∙g−1 to 5.93×106 copies∙g−1 in dry soil, being significantly higher in alfalfa field than in farmland. The correlation analysis between the abundance of nifH gene and physicochemical factors of nitrogen-fixing microorganisms showed that soil nifH gene abundance was positively correlated with bulk density (P=0.009) and soluble carbon content (P=0.005), positively correlated with total nitrogen (P=0.044) and available potassium content (P=0.013), and negatively correlated with total phosphorus content (P=0.000), and nitrate content (P=0.023). A total of 176367 valid sequences were obtained, belonging to 5 phyla, 8 classes, 11 orders, 15 families and 17 genera. Proteobacteria and Cyanobacteria were the dominant phyla, accounting for 95.9%−98.9% and 0.2%−1.8% of the total sequences of the samples; whereas Skermanella and Azohydromonas were the dominant genera, accounting for 82.2%−87.6% and 1.6%−4.6%. Compared with farmland, continuous alfalfa significantly increased the relative abundance of Skermanella, but the relative abundance decreased with the increase of alfalfa planting years. Long-term cultivation of alfalfa propagated the rare microbial taxa, including Azotobacter, Burkholderia, Frankia, Mesorhizobium, Geobacter and Bradyrhizobium, whereas Clostridium, Rhodopseudomonas and Trichormus were sterilized. RDA analysis showed that there was niche differentiation for nitrogen-fixing bacterial community in response to environmental factors, but soil total phosphorus, organic carbon and nitrate nitrogen were the dominant environmental factors for the nitrogen-fixing bacterial community structure. The analysis of molecular ecological network showed that there were 520 nodes (OTUs) and 4170 edges in the network of nitrogen fixing microorganisms in maize field and alfalfa soil, among which 24 nodes belonged to rich group, 93 nodes belonged to rare group, and 403 nodes belonged to transitional group. There was one internal connection of rich taxa, 2187 internal connections of transitional taxa, and 358 internal connections of rare taxa. And nitrogen-fixing bacteria had a cooperative relationship in the ecological network, with relatively stable community structure and strong adaptability to environmental changes. This study provides basic data and theoretical basis for the diversity of nitrogen-fixing microorganisms in loess soil and the determination of suitable planting period of alfalfa.
Measurement and analysis of agricultural green total factor productivity based on farmers’ perspective
CHENG Yongsheng, ZHANG Deyuan, WANG Xia,
, Available online  , doi: 10.12357/cjea.20220562
Abstract(83) HTML (40) PDF(9)
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Enhancing agricultural green total factor productivity and accelerating green transformation of agriculture are inevitable choices for building a strong socialist modernization country in a comprehensive manner. Based on the comparative analysis of micro-measurement methods, the study analyzes the status of agricultural green total factor productivity at the farm household level based on the technically optimized Malmquist-Luenberger index. The kernel density estimation method and the Dagum Gini coefficient method were further used to reveal the dynamic evolution of agricultural green total factor productivity and its regional differences in the micro sample. The main findings are as follows: 1) from the measurement results, the mean value of agricultural green total factor productivity in the micro field during the sample period is 1.0030, with a good overall development trend. The mean value of agricultural green total factor productivity of farmers in 2016 is 1.0099, and agricultural green development is in a good growth trend. The mean values of technical efficiency change and technical progress change are 1.0165 and 0.9928, indicating that the improvement of farmers’ green agricultural technical efficiency is the main driving factor, while the change of technical progress is relatively slow. By 2018, the mean value of green total factor production of farmers was 0.9960, which showed a decreasing trend. The corresponding mean values of technical efficiency change and technical progress change were 0.9765 and 1.0200, indicating that the technical efficiency improvement of green agriculture did not achieve a sustainable spillover effect, and the innovation function of technical progress change played a role in boosting. 2) In terms of contributing factors, whether using subjective environmental assessment scores or objective provincial-level environmental pollution data as proxies for non-desired outputs, among farmers with higher levels of agricultural green total factor productivity, agricultural green technological progress and agricultural green technological efficiency were found to be more effective. In farmers with high levels of agricultural green total factor productivity, both green technological advances and green technological efficiency in agriculture are the drivers of green growth, and the contribution of the latter is greater than that of the former. The former is significantly worse than the latter in terms of regression. Therefore, the improvement and optimization of farmers’ resource allocation, management mode and organization is the key to enhance the agricultural green total factor productivity at the present stage, and its impact is relatively higher than the innovation of agricultural production technology. 3) From the perspective of dynamic evolution pattern, in terms of agricultural green total factor productivity, the concentration in 2016 and 2018 is high, showing distinct clustering, the divergence phenomenon is not obvious, and the number of farmers with high level of green development in 2018 is much higher than that in 2016; in terms of agricultural green technical efficiency of farmers, there is no bifurcation in 2016 and 2018. The number of low-level farmers in 2018 is more than that in 2016, there is a regression phenomenon, and the difference between the agricultural green technical efficiency of high and low-level farmers is obvious; in terms of agricultural green technical progress of farmers, the overall is in the rising stage, the number of low-level farmers in 2016 is less, and the number of high-level farmers is relatively more, while in 2018, the number of high and In 2018, the number of high and low level farmers remained the same, and the spatial clustering effect appeared. In 2018, the number of farmers with low level of agricultural green technology progress decreased “precipitously”. On the premise that the number of farmers remained unchanged, this part of low level farmers moved to the middle and high level groups, forming the dynamic transfer effect of “internal push and external pull” is formed. Therefore, in comprehensively promoting the modernization of agriculture and rural areas and accelerating the process of green transformation of agriculture, we should be alert to and prevent the “polarization” of farm households. 4) From the perspective of regional disparity, the overall gap of agricultural green total factor productivity in the sample period is decreasing, with a decline of 22.32%. From the source decomposition, the hyper-variance density is the main cause of the overall regional disparity in agricultural green total factor productivity; from the contribution rate, the contribution rate of hyper-variance density is much higher than the contribution rate of intra- and inter-regional disparity, indicating that the cross-over problem between different regions is the main cause of the overall disparity in agricultural green total factor productivity at the farmer level. Further, from the intra-regional disparity, the disparity of agricultural green total factor productivity at the household level decreases within the eastern and western regions; from the inter-regional disparity, the disparity between the eastern-western, eastern-central, and central-western regions decreases continuously during the sample period and the synergy is the strongest, but this gap is vulnerable to environmental factors.
Effects of new acidification methods on nitrogen conversion during agricultural waste composting
ZHANG Lu, WANG Hongge, WANG Weishuai, WANG Xuan, GUO Weiting, LIU Shuang, WANG Hong, MA Lin
, Available online  , doi: 10.12357/cjea.20220746
Abstract(65) HTML (32) PDF(11)
Abstract:
Aerobic composting is a common way to treat agricultural waste. However, a large amount of nitrogen is lost during composting, which has become an important problem in agricultural waste composting. Material acidification is an effective method to reduce nitrogen loss during composting process, while conventional acidification using inorganic acids has disadvantages such as high cost and secondary pollution. Optimizing the acidification process is of great significance for reducingnutrient loss and environmental pollution during composting process. In this study, an acid conditioner was prepared by anaerobic fermentation of lactic acid bacteria with food residues (fruit dregs and soybean dregs) as substrate, which was rich in lactic acid (70 mmol·L −1) and lactic acid bacteria (106 cfu·mL −1). Two acidizing methods were designed by using the acid conditioner:1)a certain amount of acid conditioner (30%, w/w) was added directly to acidify the material (MA); 2) a small amount of acid conditioner (3%, w/w) was added and there was no forced ventilation for the first 3 days of composting to enable the lactic acid bacteria in acidic conditioners to function, lactic acid bacteria can produce lactic acid to achieve self-acidification of compost materials (LA). Meanwhile, we set up the experimental treatment of adding sulfuric acid (SA) and no acidification (CK) respectively. The changes of physicochemical properties (temperature, pH, EC, GI, OM) and nitrogen forms (NH3, N2O, Org-N, NH4+, NO2, NO3) during the composting process of agricultural waste were analyzed. The results showed that the compost products treated by three acidification methods all reached the standard of maturity (GI>80%), and the MA treatment was the best (GI=117.8%). The duration of the thermophilic phase (>50 ℃) of CK, MA, SA and LA was 10, 10, 9 and 7 days, respectively, all of which reached the harmless standard (>50 ℃ at least 7 days). The TN loss of MA, SA and LA decreased by 14.0%, 25.6% and 22.2%, and NH3 volatilization decreased by 26.0%, 36.5% and 54.9% compared with CK, respectively. Acidification treatment increased the NH4+ content, promoted nitrification, and indirectly enhanced denitrification. MA and LA treatments reduced N2O emission by 23.1% and 69.4%, while SA treatment inhibited N2O reduction and increased N2O emission by 18.3%. The ReCiPe evaluation method was also used to evaluate the total environmental burden of the different acidification treatments. The total environmental burden of MA, SA and LA decreased by 34.5%, 11.0% and 55.9% compared with CK, respectively, indicating that acidification is an effective way to reduce the environmental burden of composting. By comparing the economic benefits of the three acidizing methods, it is found that the costs of MA and LA treatments are 18.4 yuan and 0.87 yuan respectively for reducing the emission of 1 kg active N, which is far lower than that of SA treatment 91.3 yuan. These results indicate that the MA and LA acidification modes are economically feasible. In conclusion, MA and LA treatments can be a feasible method to reduce nitrogen loss during composting process. This study provides a new theoretical basis for composting acidification and nitrogen conservation technology, as well as a new scheme for the collaborative treatment of multi-source waste.
Distribution characteristics of soil fungi community in rhizosphere of foxtail millet under different planting patterns
WANG Genquan, HAO Xiaofen, GUO Erhu, YANG Huiqing, ZHANG Aiying, CHENG Qiaolin, QIN Yuzhong, WANG Jun
, Available online  , doi: 10.12357/cjea.20220577
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Abstract:
There are continuous cropping obstales in foxtail millet. To understand the effects of continuous cropping of foxtail millet on soil fungal community structure, we explored the distribution characteristics of fungal community of the rhizosphere soil using the fungal ITS high-throughput sequencing technology under different cropping strategy, including foxtail millet - maize rotation, foxtail millet continuous cropping for 3 years, and foxtail millet continuous cropping for 5 years, and the abandoned land taken as control. The results showed that a total of 10 phyla, 24 classes, 46 orders, 79 families, 136 genera and 146 species of fungi were detected in the rhizosphere soil of foxtail millet under different cropping strategy. At the phylum and class level, the population structure was relatively stable. The dominant phylum in soil mainly consisted of Ascomycota and Basidiomycota, while the dominant classes were Sordariomycetes, Dothideomycetes and Pezizomycetes. At the order level, the relative abundance of Sordariales in the rhizosphere of foxtail millet was 2 times more than that in the abandoned land. At family and genus level, the relative abundance of Mortierellaceae and Mycosphaerellaceae was higher, while the relative abundance of Alternaria, Didymella and Clonostachys was lower in rotation soil compared to continuous cropping soil. Alpha diversity analysis exhibited that the fungal abundance of the rhizosphere soil was of significant difference under foxtail millet - maize rotation and foxtail millet continuous cropping (P<0.05), and that under the rotation soil was the highest. Beta diversity analysis revealed that the fungal structures of the rhizosphere soil under continuous cropping for 3 years and 5 years were similar, and they were of difference from that under the abandoned cropping or the rotating cropping, indicating that the fungal community structure in the rhizosphere soil of foxtail millet was changed under different cropping strategy. Correlation analysis showed that Alkali-hydrolyzed nitrogen was significantly positive correlated with organic matter (P<0.01), and significantly correlated with available phosphorus and urease activities (P<0.05), while the activity of polyphenol oxidase was positive correlated with available potassium (P<0.05), and significantly positive correlated with Chao1 index and Observed species index(P<0.01). Redundancy analysis (RDA) indicated that CK, CR, TC and FC were affected by Chaetomium, Mycosphaerella and Microdochium, Botryotrichum, Chaetomidium and Didymella, respectively. LEfSe analysis identified distinctly specific markers of the rhizosphere soil of foxtail millet under different cropping strategy. The markers of rhizosphere soil contained Mortierella and Mycosphaerella for the rotating cropping, Botryotrichum, Didymella and Clonostachys for 3 years of continuous cropping Alternaria and Didymella,for 5 years of continuous cropping, respectively. All in all, the soil fungal community structure under millet - maize rotation croping, exhibiting more saprophytic bacteria and less pathogenic bacteria, was significantly different from that under foxtail millet continuous cropping, which provided useful information for the study on the continuous cropping obstacles of foxtail millet.
Spectral characteristics of soil dissolved organic matter in different rice and shrimp cultivation technology models
LIANG Yihao, NI Caiying, LIU Xingxing, LI Yanliang, LIU Fangping, XU Tao
, Available online  , doi: 10.12357/cjea.20220602
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Abstract:
Rice and shrimp cultivation mode is the largest cultivation model in China and also an important part of ecological agriculture. However, in the process of cultivation, the activities have obviously changed the physical and chemical properties of many field soils, which had a significant effect on the change of organic matter. Dissolved organic matter (DOM), as one of the most active parts of organic matter, is also the subject of modification, but there are few related studies on the characteristics of modified dissolved organic matter. Therefore, in this study, ultraviolet-visible absorption spectra and three-dimensional fluorescence spectra were used to calculate different spectral parameters, combined with parallel factor analysis (PARAFAC), to study the characteristics of soil DOM under different rice and shrimp cultivation technology models. The results showed that there are weak shoulder peaks in the UV-Vis absorption spectrum of soil DOM in all modes (260 nm~280 nm), and the absorbance decreases with the increase of wavelength, and gradually approaches 0, the UV-Vis absorption spectral parameters SUVA254 and UV254 of soil DOM in different rice and shrimp cultivation modes were lower than those of traditional rice monoculture, the E2/E3 values were smallest in the integrated rice crayfish system (RS0), and the SR values of the two co-cropping modes are averaged from 0.5 to 2.0; in all modes, the mean value of fluorescence index (FI) >1.9, Humification index (HIX)<4, Biologcal index (BIX) is 0.6−0.7; all rice and shrimp cultivation technology models have resolved 2 protein-like components (C1, C3) and 2 humic-like components (C2, C4) , C1 accounted for a higher proportion and was negatively correlated with other components, and the remaining components were positively correlated with each other. Principal component analysis obtained 4 effective components, which are arranged according to the contribution rate: PC1 representing the concentration and aromaticity of DOM, PC2 representing the biological characteristics, molecular weight, and degree of humification of DOM, PC3 representing the protein components and autogenic features in DOM, PC4 representing molecular structure of DOM. The above results prove that there are many unsaturated aromatic structure molecules in soil DOM of all models, rice and shrimp cultivation reduced the degree of humification and aromaticity of soil DOM; integrated rice crayfish system (RS0) had largest molecular weight of soil DOM, and had certain exogenous characteristics, and the soil fertilizer retention ability was better, the comprehensive benefit is the best among the three rice and shrimp farming models; there is no significant difference in the material composition of soil DOM under different models, which is related to the indirect effects of agricultural management practices. The source of C1 is different from other components, which maybe is related to the decomposition and transformation of DOM by microorganisms. In addition, the difference in flooding is one of the main reasons for the difference in soil DOM characteristics, the soil releases DOM and DOC through flooding, which significantly affects the characteristics of soil DOM. In production practice, attention should be paid to the application of organic fertilizers, which can maintain soil fertility, increase DOM and microbial diversity, to maintain soil fertility, while also monitoring the status of contaminants to soil and crops in farmland.
Spatiotemporal pattern of tea industry in Sichuan province and their driving forces based on the geographical detector
CAO Jie, LIN Zhengyu, CHEN Chunyan, LIU Yuanli, GAO Wenbo, SHAO Zhouling
, Available online  , doi: 10.12357/cjea.20220278
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Abstract:
Tea industry expansion results from the interactions of the natural and social factors. A understanding of the Spatiotemporal pattern change characteristics of tea industry and a reveal of result of the effects of physical and socioeconomic factors are helpful to provide an important basis for the adjustment of tea planting structure. Based on the statistical yearbook data of tea industry in Sichuan province for 40 years from 1980 to 2019, the Spatiotemporal pattern change characteristics of tea industry in Sichuan and their driving forces were studied by using the industrial concentration, exploratory data analysis and industrial gravity model. Natural factors such as elevation, the hydrogen ion concentration(pH) of soil, annual precipitation, accumulated temperature, average temperature of growing season, extreme minimum temperature of overwintering period and extreme maximum temperature of growing season, production factors such as land use intensity, labor, fertilizer, pesticides and irrigation, as well as socioeconomic factors such as per capita disposable, technology and policy were statistically divided by the geographical detector, and the impact of separate driving factors and the interactions between these factors on spatial pattern of tea industry in Sichuan province were systematically discussed. The results of this study were as follows. In the past 40 years, the tea industry space in Sichuan province showed an expanding trend, the spatial distribution showed a high degree of concentration and wavelike rose with time (locational Gini index > 0.5). There was a significant geographical agglomeration on the county scale, showing a spatial structure of hot in the southern Sichuan and southern Chengdu Plain (Global Moran’s I > 0). The center of gravity of tea industry space in Sichuan migrated to the west. In the geographical detector, the modifiable areal unit problem (MAUP) is a fundamental issue. To address this issue, both scale effect and zoning effect are tested to examine the MAUP before the geographical detector model was applied in this work. Among the 15 factors selected, land use intensity, labor, fertilizer had higher decisive power. The interactions between these factors mainly manifested dual-factor enhancement type and nonlinear enhancement type, And average the interaction of industry and socioeconomic factors had highest decisive power (0.8870). So the tea industry space in Sichuan Province is mainly driven by factors of industry. Evidence-based hypothetical solutions deriving from these observations focused on three aspects: 1) pay close attention to the influence of lack of water in tea growth period, intense rainfall and freezing damage on tea tree and react effectively. 2) corresponding countermeasures were purposed, including the aspects of strengthening the construction of machine-plucking tea gardens "suitable for mechanization" and establishing the concept of green development. 3) accelerate the promotion and application of modern, agricultural technology, breed new tea varieties which fit to local conditions, as well as set up the system of steady land, labor, fertilizer and pesticides input.
Effects of nano-Si on plant growth and carbohydrates accumulation of tomato under low temperature
GUO Shuxun, DAI Zemin, YANG Ran, JI Chen, SHI Yu, ZHANG Yi
, Available online  , doi: 10.12357/cjea.20220773
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Abstract:
Low temperature is one of the main limiting factors of the development of facility agriculture in the North of China. Agricultural producers urgently need a cheap and convenient agronomic measure to improve tomato resistance to low temperature. The aim of this study was to investigate the effect of nano-Si on root system architecture and the accumulation mechanism of non-structural carbohydrates at low temperature. We focused on the changes in root growth and development and non-structural carbohydrate accumulation patterns of tomato seedlings with the application of nano-Si at low temperature. In this study, the cultivated tomato ‘Zhongza 9’ by substrate cultivation was used as the test material, the effect of leaf spraying nano-Si (0 mg∙L−1 and 100 mg∙L−1) on tomato biomass, root system architecture, photosynthetic capacity and non-structural carbohydrate content was studied under room temperature(25 ℃/16 ℃, day/night) and low temperature(15 ℃/6 ℃, day/night). The results showed that: 1) At low temperature, the biomass, total root length, number of root tips, photosynthetic pigment content and net photosynthetic rate of tomato were significantly decreased(P<0.05), while the root activity, soluble sugar, sucrose and starch contents were significantly increased(P<0.05), and shoot fresh weight, net photosynthetic rate and total root length were decreased by 48.60%, 66.88% and 65.49%, respectively(P<0.05). 2) Application of nano-Si significantly increased tomato biomass, root activity, root tip number, fractal dimension, net photosynthetic rate and non-structural carbohydrate content at room temperature and low temperature(P<0.05), among which application of nano-Si at low temperature increased root tip number, net photosynthetic rate and leaf soluble sugar content by 35.25%, 48.24% and 75.69%, respectively(P<0.05). In conclusion, low temperature severely restricts photosynthesis, root growth, transport of non-structural carbohydrates in tomato leaves, and root system architecture parameters tend to change in directions that are not conducive to plant growth. The application of nano-Si could improve the cold resistance of tomato by promoting the synthesis of photosynthetic pigments, increasing photosynthetic rate, increasing root activity, improving root system architecture and increasing the synthesis of non-structural carbohydrates.
Effects of intercropping oat with different crops on community structure of soil nematodes and crop yields
WANG Yanan, QIAO Yuejing, FAN Yaqi, HUO Ruixuan, GUO Laichun, YANG Zhenping
, Available online  , doi: 10.12357/cjea.20220512
Abstract(93) HTML (59) PDF(19)
Abstract:
Intercropping is an important planting mode for sustainable use of land resources, while soil nematode is an indicator of soil health, which can reveal the function of food web in underground ecosystem. In order to explore the effects of different intercropping patterns of oats on yield and soil nematode communities, five treatments were set up, which were oat monoculture, oat||soybean, oat||rice bean, oat||potato, oat||sweet potato. The effects of different intercropping patterns of oats on crop yield and the number, diversity and community structure of soil nematodes were analyzed to screen out the better intercropping pattern of oats. The results showed that compared with monoculture, intercropping mode had certain advantages in land utilization rate and total crop yield. The intercropping pattern of oat||soybean was highest in the land equivalent ratio (1.56). A total of 39 genera were identified, including 12 Bacterivores nematodes, 4 Fungivores nematodes, 13 Plant-parasites nematodes and 10 Omnivores-predators nematodes. The four oat intercropping patterns significantly reduced the relative abundance of plant parasitic nematodes, increased the relative abundance of beneficial nematodes (bacterivores and fungivores), and optimized the soil nematode community structure. Among them, the most excellent intercropping pattern was oat||soybean: the highest proportion of microbial-feeding nematodes (88.42%) and the lowest proportion of plant-parasites nematodes (6.31%). At the same time, the intercropping pattern of oat||soybean was significantly higher than that of oat monoculture (P<0.05) in multiple ecological indexes (Wasilewska index, nematode channel ratio、Shannon-Wiener index and enrichment index), and was also the best among the four intercropping patterns. The enrichment index (EI) of oat||rice bean intercropping was the highest, and the plant parasite index (PPI) was the lowest, indicating that the soil nematode community was the lowest disturbed. The enrichment index (EI) and structure index (SI) of each cropping pattern was lower than 50, and the soil nematode food web was in the D quadrant, indicating that the soil environment was in a stress state, the food web was degraded, and the soil nematode community was unstable in the experiment location. Pearson correlation analysis showed that soil nematode community ecological indexes were correlated with soil physical and chemical properties, Organic matter was significantly negatively correlated with evenness index (r=−0.635*) and extremely significantly negatively correlated with Shannon-Wiener index (r=−0.641**), and significantly positively correlated with plant parasitic index (r=0.633*). There was an extremely significant positive correlation between available K and nematode channel ratio (r=0.722**), increasing available K could change the decomposition pathway of soil organic matter and make bacteria contribute more to the decomposition of soil organic matter. In conclusion, intercropping could optimize soil nematode community structure, improve soil ecological environment and increase crop yield. Among the four intercropping patterns, oat||soybean was the best mode, not only had the highest yield, but also had the most beneficial nematode community structure for soil health, which showed the strong production and ecological advantages of traditional Gramineae and Leguminosae intercropping.
Effects of wheat/safflower intercropping on rhizosphere microbial community function and structure
WANG Xiangsheng, LIAN Yanhao, GUO Hui, REN Yongzhe, XIN Zeyu, LIN Tongbao, WANG Zhiqiang
, Available online  , doi: 10.12357/cjea.20220354
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To study the structure and function of rhizosphere soil microbial community under wheat/safflower intercropping system are of great significance for the construction of reasonable wheat/safflower intercropping pattern and regional suitability evaluation. In this study, wheat/safflower intercropping (2∶1) pattern was set in the field, wheat monoculture and safflower monoculture as controls, based on Illumina Miseq high-throughput sequencing platform, the community structure and functional changes of bacteria and fungi in rhizosphere soil of wheat/safflower intercropping were studied, and safflower and wheat yield was measured at maturity stage. The results showed that the wheat/safflower intercropping land equivalent ratio of 1.01, the intercropping advantage is not obvious. The results of rhizosphere microbial diversity index analysis of wheat and safflower showed that intercropping increased the bacterial diversity and fungal richness of wheat rhizosphere, but significantly decreased the bacterial richness and fungal diversity. Intercropping significantly increased bacterial diversity in the rhizosphere of safflower, but decreased fungal diversity and bacterial and fungal richness in the rhizosphere of safflower. The results of principal coordinates analysis (PCoA) and equilibrium analysis of rhizosphere soil microbial community showed that intercropping significantly changed the microbial community structure in the rhizosphere of safflower(P<0.05). Proteobacteria, Acidobacteria and Bacteroidetes were the dominant bacteria in the rhizosphere of wheat and safflower, the total proportions of average relative abundance respectively were 65.94%, 70.57%, 71.39% and 70.07% in wheat and safflower monocultures and intercropping. Ascomycota and Basidiomycota were the dominant fungi, the total proportions of average relative abundance respectively were 75.99%, 68.17%, 93.23% and 69.88%. Intercropping significantly increased the relative abundance of Acidobacteria, Rokubacteria and Mortierellomycota in the rhizosphere of safflower (P<0.05), but had no significant effect on wheat. Functional prediction results showed that intercropping significantly improved nutrient cycling processes such as ammonia oxidation, nitrification, fermentation and nitrate reduction in the rhizosphere of safflower (P<0.05). Combined with correlation analysis results, MND1 was significantly positively correlated with these processes (P<0.05), and its relative abundance in the rhizosphere of safflower was significantly higher in intercropping than monoculture (P<0.05). In addition, intercropping significantly increased the relative abundance of arbuscular mycorrhizal functional genes in the rhizosphere of safflower, and significantly decreased the relative abundance of plant pathogenic functional genes (P<0.05). At the genus level, intercropping significantly increased the relative abundance of beneficial bacteria such as Moralella and Wickerhamomyces in the rhizosphere of Safflower. The relative abundance of pathogenic fungi belonging to Fusarium and Alternaria was significantly decreased (P<0.05). In conclusion, under the intercroppingwheat/safflower system, safflower at a competitive disadvantage can improve rhizosphere microbial community composition and nutrient cycling process, thus alleviating the disadvantage in a nutrient competition. Co-occurrence network analysis results show that intercropping could improve the complexity of rhizosphere microbial network of wheat and reduce the complexity of rhizosphere microbial network of safflower to some extent. In addition, Fusarium is located in the center of the rhizosphere microbial network of safflower, and intercropping can significantly reduce the number of Fusarium by affecting the interactions between the rhizosphere microorganisms of safflower. In addition, intercropping could significantly reduce the relative abundance of pathogens in the rhizosphere of safflower, which was of great significance to reduce the occurrence of safflower diseases and the total amount of pathogens in the soil.
Drivers of evapotranspiration increase in the Baiyangdian Catchment
Christine Mushimiyimana, LIU Linlin, YANG Yonghui, LI Huilong, WANG Linna, SHENG Zhuping, Auguste Cesar Itangishaka
, Available online  , doi: 10.12357/cjea.20220121
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Abstract:
Baiyangdian Catchment is facing a growing shortage of water resources. Identifying the sensitive drivers of evapotranspiration (ET) changes from land and crop management will be critical to understanding the reasons for mountainous runoff reduction and depletion of groundwater resources in the plain. It will also be important for making Xiong’an become a Future Example City for green and sustainable development. In this study, remotely sensed ET data from PML V2 products with a spatial resolution of 500 m was used to analyze the trend of ET at the pixel level and to understand its influence on vegetation such as GPP (Gross Primary Production) and NDVI (Normalized Difference Vegetation Index) under different land-use types for 2002‒2018. Results showed that there was a significant increase in ET in mountain regions and a slight increase in plain regions of the catchment. The spatial pattern of mean annual ET was very much relevant to the changing trend of GPP and NDVI. For the whole catchment, the average increases of ET, GPP, and NDVI were respectively 2.4 mm, 9.8 g∙cm−2, and 0.0021 at an annual rate. In the mountainous region, changes in annual precipitation and vegetation recovery together caused a total increase of ET by 56.5 mm over the period and negatively affected the runoff. In the plain region, there were 3 factors influencing the change of ET. While intensification of urbanization and reduction in the cultivation of wheat, the water consumptive crop, had both resulted in the decrease of ET and water consumption, ET or water consumption in most irrigated fields increased. Since the beneficial effects from urbanization and crop adjustment were not enough to offset the increase of ET in irrigated fields, an overall ET increase of 6.4 mm over the period was found. In conclusion, both in the mountainous and plain regions, ET increased. And therefore, more efforts are needed to control the ET increase in natural vegetation and cropland for a green and sustainable catchment.