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Effects of green manure incorporation combined with nitrogen fertilizer reduction on soil respiration and its temperature sensitivity in regard to wheat fields
YANG Xuehui, YU Aizhong, CHAI Jian, LI Yue, WANG Feng, WANG Pengfei, LYU Hanqiang, WANG Yulong, SHANG Yongpan
 doi: 10.12357/cjea.20230313
Abstract(71) HTML(33) PDF(7)
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This study was conducted to explore the effects of green manure incorporation combined with nitrogen fertilizer reduction on the soil respiration dynamics of wheat fields and wheat yield in oasis irrigation areas. This study was performed to provide a theoretical basis for the study of carbon emission reduction in farmlands in arid oasis irrigation areas. The experiment was conducted in 2021 and 2022 in the Hexi Oasis irrigation area. With the conventional nitrogen application without green manure (N100) as the control, we performed the following treatments: 15 000 kg∙hm−2 green manure +85% nitrogen fertilizer (G1N85), 22 500 kg∙hm−2 green manure +85% nitrogen fertilizer (G2N85), 30 000 kg∙hm−2 green manure +85% nitrogen fertilizer (G3N85), 15 000 kg∙hm−2 green manure +70% nitrogen fertilizer (G1N70), 22 500 kg∙hm−2 green manure +70% nitrogen fertilizer (G2N70), and 30 000 kg∙hm−2 green manure +70% nitrogen fertilizer (G3N70). There were seven treatments in total. Soil respiration rate, carbon emissions, yield, and carbon emission efficiency during the wheat growth period were explored, and the response of soil respiration to soil temperature was analyzed. The results showed that the soil respiration rate under different treatments showed a single-peak trend of initially increasing and then decreasing, and the variation range was 0.8 to 6.2 μmol∙m−2∙s−1 during the whole growth period. The combination of green manure incorporation and nitrogen fertilizer reduction significantly increased the soil respiration rate and the total soil carbon emissions of wheat fields. When compared with N100, the average increases were 7.2%−19.8% and 5.7%−18.8%, respectively. G3N85 and G3N70 increased the soil respiration rate by 2.3%−16.0% and 3.3%−19.8%, the total soil carbon emissions by 2.9%−15.2% and 3.1%−18.8%, respectively (P<0.05), when compared with the other treatments. Compared to G3N85, the average soil respiration rate and total soil carbon emissions of G3N70 treatment increased by 3.3% and 3.1%, respectively (P<0.05). Green manure incorporation combined with nitrogen fertilizer reduction significantly decreased the temperature sensitivity of soil respiration (Q10), and when compared with N100, the Q10 values decreased by 10.4%−18.1% (P<0.05). Green manure incorporation combined with nitrogen fertilizer reduction could significantly affect wheat yield and soil carbon emission efficiency, with the G3N85 treatment significantly higher than the other treatments by 4.2%−45.6% and 0.3%−26.4% (P<0.05). In conclusion, green manure incorporation combined with nitrogen fertilizer reduction enhanced the soil respiration of wheat fields while reducing the temperature sensitivity of soil respiration. It also improved wheat yields and carbon emission efficiency. Green manure incorporation at 30 000 kg∙hm−2 combined with nitrogen fertilizer reduction by 15% (G3N85) proved to be an effective way for nitrogen reduction and emission mitigation while improving soil productivity for wheat fields in Hexi Oasis irrigation area.
Effects of manure/biological agent-straw strip mixing on the composition of organo-inorganic complexes and characteristics of organic carbon distribution in black soil
HE Li, WU Jinggui, LI Jianming, ZHENG Shuang
 doi: 10.12357/cjea.20230351
Abstract(21) HTML(9) PDF(0)
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Strip fertilization was conducted in the black soil area of Yushu City, Jilin Province, in April 2020 according to the principle of equal carbon to explore the composition and distribution characteristics of organo-inorganic complexes in black soil under the mixed application of corn straw and livestock manure/microbial agent strips returning to the field. In the second year, the strip was changed to a planting strip without fertilization. After the straw was crushed in situ, it on the next crop sowing row was stacked towards the fallow zone on both sides to form a straw-covering strip, and two consecutive years of in situ straw-returning experiments were conducted. This experiment included four treatments: strip straw cover + chicken manure (SO), strip straw cover + cow manure (SN), strip straw cover + biological agent (SJ), and strip straw cover (SCK). Organo-inorganic complexes were extracted using the gel-dispersion grouping method and divided into aqueous (G0), sodium (G1), and ultrasonic (G2) dispersion groups. The results showed that adding animal manure and biological agents increased the soil component complexes and their carbon content compared to SCK, with the highest increases of G0 observed under the SJ treatment in 2022 at 38 g∙kg−1 and 1.74 g∙kg−1, respectively. In 2021, among the treatments of animal manure and biological agents, the G1 complex content under the SJ and SO treatments significantly increased by 33.46–37.66 g∙kg−1 compared to that under the SN treatment, and the organic carbon content increased by 0.69–0.78 g∙kg−1. The organic carbon content of the G2 complex under SJ and SO treatments showed significant differences compared to that under SN treatment. In 2022, among the animal manure and bacterial agent treatments, the carbon content of the G0 complex under SJ and SO treatments increased significantly compared to that under SN treatments, with the highest increase being 1.02 g∙kg−1. The content of the G1 complex under SJ treatment significantly increased by 41.25 g∙kg−1 and 49.92 g∙kg−1 compared to that under SO and SN treatments, respectively. The SJ treatment showed the highest organic carbon content in the G2 complex. Between two years, the content of the G0 complex under SJ treatment increased by 23.35–23.74 g∙kg−1 compared to that under SO treatment. Scanning electron microscope and X-ray diffraction phase analysis showed that the mixed application of manure/biological agent straw effectively maintained the surface structure of the complexes and improved the organic carbon conversion rate. In summary, applying corn straw mixed with biological agents is more conducive to improving soil fertility and enhancing soil carbon sequestration and can be selected as the optimal returning mode.
Impact of cultivated land operating scale on the ecological efficiency of farmers’ rice production: a case of Changde City
WEN Gaohui, HUANG Danni, XIE Yilin, HU Xianhui
 doi: 10.12357/cjea.20230294
Abstract(75) HTML(54) PDF(10)
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Improving the ecological efficiency of rice production is key to achieving the dual goals of guaranteeing the stable growth of grain production and reducing the environmental loss of cultivated land use. Cultivated land is the basic source of agricultural production. Therefore, exploring the impact of cultivated land operating scale on the ecological efficiency of rice production by farmers is of great importance in promoting moderate-scale agricultural operations and the sustainable utilization of cultivated land. Unlike other studies that have mostly focused on the medium and macro dimensions of cities and provinces, this study was based on the micro dimension of grain production—farmers’ perspectives. Moreover, the conclusions obtained from this study can compensate for the lack in previous studies in terms of targeted exploration on the impact mechanism of cultivated land operating scale on farmers’ rice production (ecological) efficiency and the existence of a nonlinear relationship between them. Using data from 416 questionnaire surveys from farmers in Changde City, a random frontier analysis method was used to construct an efficiency calculation model and an impact model to empirically test the relationship between cultivated land operating scale and the farmers’ ecological efficiency of rice production. The results were: 1) Farmer scale levels and the rice production ecological efficiency need to be improved. Among the sample farmers, the number of smaller operating scale farmers was the highest, accounting for 94.95% of the total sample, indicating that small-scale farmers remain the main forces of agricultural production. The average farmers’ ecological efficiency of rice production was 0.830, with a room for improvement of 0.170. 2) Cultivated land operating scale had a significant impact on the farmers’ ecological efficiency of rice production. The ecological efficiency of rice production by farmers tended to increase and then decrease with the expansion of the cultivated land operating scale. Their relationship was non-simple linear but exhibited an “inverted U” with an inflection point located in the range of 1.2−1.4 hm2. It is not necessarily true that the larger the cultivated land operating scale, the higher the ecological efficiency of rice production by farmers. The blind expansion of the cultivated land operating scale could lead to a decrease in the farmers’ ecological efficiency of rice production. Therefore, it is necessary to promote moderate-scale cultivation of cultivated land. 3) The farmers’ ecological efficiency of rice production was also significantly positively affected by the education level of the household head, dependency ratio, and the proportion of agricultural income. It was significantly negatively affected by the age of the household head. The aforementioned information indicates that we must recognize that small-scale farmers will continue to exist for a long time. Based on this, we should further increase plot sizes to promote moderate-scale cultivation of cultivated land and promote cultivated land concentration to reduce the degree of cultivated land fragmentation. Furthermore, the government should not only continuously promote fertilizer reduction and efficiency improvement to accelerate the development of low-carbon agriculture, but also develop new farmers and increase their support to promote the ecological transformation of rice production.
Effects of fertilizers application on soil nematode communities and oat yield in saline-alkali dryland
QIAO Yuejing, HUO Ruixuan, ZHAO Luming, LI Qingshan, FAN Yaqi, GAO Duo, ZHANG Lijing, GUO Laichun
 doi: 10.12357/cjea.20230376
Abstract(64) HTML(23) PDF(3)
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Utilizing saline-alkali land is of great significance for enhancing cultivated land quality. Nematodes are fauna critical to the soil food web that are morphologically and functionally diverse and widely used to indicate soil quality. However, the ecological indicator function of the nematode community on oat saline-alkali land, particularly the application of industrial waste on saline-alkali land, has less been reported. In this study, soil nematodes were investigated as an indicator of the soil ecological environment to explore the effects of the long-term application of different fertilizers on the micro-food web of saline-alkali barren soil under dry farming. Based on a 5-year experiment, seven treatments were set: combined application of vinegar residue and fly ash (VRF), vinegar residue application (VR), organic manure application (OM), bacterial manure application (BM), combined application of organic manure and chemical fertilizer (OCF), chemical fertilizer application (CF), and no fertilization (CK). Soil samples were collected from the plow layer at the seedling, heading, and harvesting stages of oats, and the soil nematode community, soil traits, and oat productivity under long-term application of different fertilizers were analyzed. The results showed that most fertilizer treatments reduced soil pH and bulk density and significantly increased contents of organic matter, nitrate nitrogen, and microbial quantity (bacteria, fungi, and actinomycetes). With the exception of BM, the yield of oats increased significantly by 44.5%−92.3% under other treatments, and OM and CF had the highest oat yield (P<0.05). The total number of soil nematodes significantly increased due to fertilization; OM was highest at the seedling and heading stages, and VR was highest at the harvesting stage (P<0.05). The enrichment index (EI) of each treatment and the structure index (SI) of most treatments were lower than 50, indicating that the soil nutrients were poor and the soil food web was in a stressed or degraded state in this experimental field. Although the nematode community under OM application reached a structured state at harvesting stage (SI>50), the food web was relatively stable, and the proportion of plant-parasitic nematodes was higher (36.2%). Compare to other fertilizers, the number of dominant species was significantly increased, and the nematode diversity was the lowest (P<0.05) under CF treatment. The combination of OM and CF (OCF) compensated for these shortcomings to some extent. VRF and VR significantly increased the proportion of microbial-feeding nematodes and decreased the proportion of plant-feeding nematodes. The Wasilewska index (WI) under the VRF and VR treatments was higher than that of CK during the three growth periods; and the maturity index (MI) of free-living nematodes under the VRF treatment was always the highest (P<0.05), which indicated that organic carbon mineralization was dominated by microbial-feeding nematodes under the VRF and VR treatments and that the food web was mature and stable with less disturbance under the VRF treatment. Soil organic matter, available P, and microorganisms were the main factors affecting the number of soil nematodes. Soil pH, EC, and bulk density were the main limiting factors for oat yield, but there was no significant correlation between the number of nematodes and oat yield, but β-glucan content was negatively correlated with the number of plant parasitic nematodes (r=−0.52*). The combined application of organic manure/chemical fertilizer and vinegar residue/fly ash was beneficial to the health and stability of the soil microecological environment.
Root and leaf senescence of maize subject to spatial differentiation of soil water and CO2 in sandy fields with plastic film mulching
ZHOU Lifeng, YANG Yuxiang, YANG Rong
 doi: 10.12357/cjea.20230289
Abstract(93) HTML(46) PDF(8)
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High intensive irrigation is commonly found in newly reclaimed oasis sandy land in arid area, which easily causes plant senescence of spring maize in farmland with plastic film mulching. The previous studies have found that land cover significantly affected soil moisture and soil aeration, but the data of spatial differentiation of soil moisture and soil aeration under mulching condition was lacking. In order to explore whether soil moisture and aeration causes plant senescence, an experiment was conducted to investigate the effects of plastic film mulching on spatial differentiation of soil water and partial pressure of soil CO2 (pCO2) in root zone, root growth, green leaf duration, leaf photosynthetic physiology, grain yield and grain quality of spring maize in a sandy farmland in the Hexi Corridor (100°12′E, 39°20′N, 1370 m above sea level). Two treatments [plastic film mulching (PFM) and no mulching (NM)] were set up in this experiment. In the current study, oven drying method was used to determine soil water content. Soil gas was collected by gas well method, which was composed of collecting pipe, transmission pipe and a sampler. The CO2 concentration of gas samples was analysed by a gas chromatograph (Agilent 7890A, Agilent, Palo Alto, USA). Plant roots were sampled using a steel drilling, washed into a nylon mesh bag, scanned with root a scanner (EPSON Perfection V700) and then obtained root length density (RLD) using WinRHIZOPro software. Soil moisture showed no significant difference in horizontal direction in NM treatment, whereas, the average soil moisture of mulched soil (narrow row and wide row at 5 cm distance from plants) was 28.1% (P<0.05), 15.2% (P<0.05) and 21.7% (P<0.05) higher than that under non-mulched soil (wide row at 25 cm distance from plants) before, 6-days after, and 9-days after irrigation. In PFM treatment, soil pCO2 in mulched zone was 40% higher than that in the in non-mulched zone. Compared with NM, the excessively high soil pCO2 under mulched zone under PFM treatment decreased the maize root activity by 19.7%, but the root distribution and activity in the non-mulch zone increased by 22.7% and 9.6%, respectively; the leaf photosynthetic rate and transpiration rate in PFM were increased by 20.0% and 8.5% at the jointing stage, respectively, but the corresponding value at grain filling stage were −40.0% and −18.0% respectively. In addition, compared with the NM, the senescence-start time and senescence-maximum time of green-leaves were 1.7 d and 7.1 d earlier in PFM, respectively, while the average and maximum green-leaves senescence rates were increased by 6.7% and 21.7% in PFM, respectively. The above effects of mulching did not significantly affect the yield of corn grain, but reduced the starch content and protein content of grain by 20.1% and 22.1%, respectively. The above results show that the excessively high soil pCO2 after maize flowering in the newly reclaimed oasis sandy land in the arid area may be an important reason of plant senescence and grain quality degradation, and it is recommended to take timely film-uncovering, controlled irrigation (e.g., deficit irrigation, root alternating irrigation) or aerated irrigation to improve soil aeration.
Effect of insect-resistant transgenic rice and its hybrid combination rice on diversity and composition of soil microbial community
SONG Yana, CHEN Zaijie, LIN Yan, HU Taijiao, WU Mingji, WANG Feng
 doi: 10.12357/cjea.20230267
Abstract(110) HTML(77) PDF(11)
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Microorganisms drive the soil material cycle and evolution of fertility, and their community composition is related to the stability and sustainability of the soil microecosystem. The study of changes in the soil microbial community in insect-resistant transgenic rice is an important part of environmental safety assessments. Based on high-throughput sequencing of the bacterial 16S rRNA and fungal ITS genes, this study analyzed the differences in diversity and composition of microbial communities in paddy soils with insect-resistant transgenic rice ‘MFB’, insect-resistant transgenic hybrid rice ‘Minfeng A/MFB’ ‘Tianfeng A/MFB’ or ‘Gufeng A/MFB’ and non-transgenic conventional rice ‘Minhui 3301’ or hybrid rice ‘Tianyouhuazhan’. The results showed that, compared with non-transgenic conventional rice ‘Minhui 3301’ or hybrid rice ‘Tianyouhuazhan’, both insect-resistant transgenic rice ‘MFB’ and transgenic hybrid rice ‘Minfeng A/MFB’ ‘Tianfeng A/MFB’ or ‘Gufeng A/MFB’ could significantly increase the yield (P<0.05). At the same time, high-throughput sequencing showed that the α-diversity indexes of Chao1, Observed_species, and Shannon of bacterial or fungal communities in paddy soil with ‘MFB’ were higher than those in soil with ‘Minhui 3301’ at all stage except for fungal communities at rice maturation stage, and the differences at rice maturation or tillering stage are significant (P<0.05). At the heading stage of rice, the values of α-diversity indexes of Shannon of bacterial or fungal communities in paddy soils with the insect-resistant transgenic hybrid rice ‘Minfeng A/MFB’ ‘Tianfeng A/MFB’ or ‘Gufeng A/MFB’ were between those of soils with ‘MFB’ and ‘Tianyouhuazhan’. The results of β-diversity analysis of bacterial or fungal communities showed that there were no significant differences in the composition of microbial communities in paddy soils with different varieties of rice in this field experiment. However, the relative abundance of Proteobacteria, which showed the highest abundance of bacteria, in paddy soil with ‘MFB’ increased compared with that of ‘Minhui 3301’, and reached the significance level at the tillering and maturation stage of rice (P<0.05). In contrast, the relative abundance of Ascomycota, which showed the highest abundance of fungi, was reduced in paddy soil with ‘MFB’ and reached the significance level at the tillering and heading stages of rice (P<0.05). At the heading stage of rice, the relative abundances of Proteobacteria and Ascomycota in paddy soils with ‘Minfeng A/MFB’ ‘Tianfeng A/MFB’ or ‘Gufeng A/MFB’ were between those of soils with ‘MFB’ and ‘Tianyouhuazhan’. According to the functional prediction of microbial communities, the differences in functional composition of bacterial communities in paddy soil between soils with ‘MFB’ and ‘Minhui 3301’ gradually increased with rice growth. In summary, insect-resistant transgenic rice and its transgenic hybrid rice increased the diversity of soil bacterial and fungal communities and changed the relative abundance of major bacterial and fungal species with increased yield, but did not have significant effects on the community and functional composition of bacteria or fungi.
Effects of salt stress on photosynthetic characteristics and canopy structure of edible sunflower leaves at budding stage
DONG Ruixiao, WANG Yongqing, WANG Xinbo, LI Yuyi, WANG Xiquan, ZHANG Hongyuan, SONG Jiashen, YU Ru, PANG Huancheng, WANG Jing
 doi: 10.12357/cjea.20230227
Abstract(97) HTML(43) PDF(13)
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To explore the effects of the degree of salt-stress on the photosynthesis of edible sunflowers (hereafter referred to as “edible sunflower”) at the budding stage, the photosynthetic characteristics of the leaves and their canopy structures were obtained after three degrees of salt stress classed as lower (LS), medium (MS), and higher (HS) total dissolved solids values (1.00, 2.68, and 4.93 g∙kg−1, respectively). The results showed that the three salt stress treatments dramatically decreased the net photosynthetic rate (Pn) of the leaves and reduced the number of leaves with high Pn. When compared with that in the LS treatment, the maximum Pn in the MS and HS treatments decreased by 5.09% and 38.69%, respectively. In addition, salt stress reduced the Pn of the top leaves. The maximum Pn values of the top leaves in the MS and HS treatments were 8.08% and 14.66% lower than those in the LS treatment, respectively. The Pn of all leaves was mainly affected by the synergistic effects of stomatal and non-stomatal factors in the LS treatment, whereas it was mainly affected by non-stomatal factors in the MS and HS treatments. Salt stress also changed the plant type of the edible sunflowers. The canopy structure of LS treatment had a pagoda shape; however, the canopy structures of MS and HS treatments were flat and cylindrical, respectively. Salt stress reduced the total and main functional leaf areas of edible sunflower. Compared with the LS and MS treatments, the total leaf area of the HS treatment decreased by 56.03% and 47.74%, respectively; the maximum single leaf area of the HS treatment also decreased by 38.71% and 49.46%, respectively. Contrarily, the maximum leaf inclination angle of the HS treatment increased by 30.92% and 14.59% compared to those of the LS and MS treatments, respectively. Concludingly, salt stress significantly reduced the photosynthetic performance and leaf area of the main functional leaves of edible sunflowers, causing the canopy structure to change from extended to contracted, thereby inhibiting normal plant growth.
Effects of different proportions of chemical fertilizer reduction combined with organic fertilizer supplements on organic carbon sequestration in Tobacco-planting soil
XIONG Yubin, YU Shunping, YANG Ya, HUANG Lin, YU Haibing, TANG Li
 doi: 10.12357/cjea.20230327
Abstract(65) HTML(18) PDF(8)
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The long-term effects of different proportions of fertilizer reduction combined with organic fertilizer on organic carbon sequestration in tobacco-planted soil were explored. Based on nine consecutive years of field positioning experiments, treatments of no fertilizer (CK), 100% fertilizer (CF-1: Local conventional recommended fertilizer), 80% fertilizer (CF-2), 80% fertilizer with organic fertilizer (OF-1), 60% fertilizer with organic fertilizer (OF-2), 70% fertilizer with organic fertilizer + bioorganic fertilizer (BOF) were applied to compare organic carbon storage profit and loss, carbon sequestration rate, organic carbon component content, organic carbon sensitivity index, soil carbon pool activity and soil carbon pool management index of tobacco-planting soil, and to explore the long-term effects of different proportions of fertilizer reduction combined with organic fertilizer supplements on organic carbon sequestration in tobacco-planting soil. The organic carbon composition, storage, and soil carbon sequestration rate of tobacco-planted soil under the continuous no-fertilization (CK) treatment were significantly lower than those of CF-1. The organic carbon content of tobacco-planted soil increased by 9.6%, 20.9%, and 13.9%, and the active organic carbon content of soil increased by 43.4%, 68%, and 41.7%, respectively. Soil soluble organic carbon content increased by 14.8%, 19.1%, and 25.4%; soil microbial biomass carbon content increased by 22.8%, 37.2%, and 36.4%, soil organic carbon storage increased by 15.3%, 30.2%, and 31.2%, respectively. The average annual carbon sequestration rate was increased by 191.3%, 382.6%, and 391.3%, respectively, and the carbon pool management index was increased by 100.8%, 159.8%, and 79.6%, respectively. Continuous fertilizer reduction at different proportions combined with organic fertilizer significantly increased the sensitivity index of soil active organic carbon. Compared with CF-1, the yield of tobacco leaves increased by 10.3%, 33.5%, and 35.3%, and the proportion of medium- and high-grade tobacco leaves increased by 14.6%, 22%, and 18%, respectively, in the three fertilizer treatments. After nine consecutive years of fertilizer reduction and supplementation with organic fertilizer, the organic carbon content and soil organic carbon sequestration rate of tobacco-planted soil significantly increased, and the quality of tobacco production was promoted. This approach is an effective way to produce green and high-quality tobacco leaves and to increase the efficiency of soil carbon sequestration. Treatment with OF-2 or BOF resulted in much better results.
Effect of nitrogen application on yield, quality and light temperature physiological characteristics of summer peanut
YANG Qirui, LI Lantao, ZHANG Xiao, MIAO Yuhong, SHENG Kai, ZHANG Duo, WANG Yilun
 doi: 10.12357/cjea.20230568
Abstract(61) HTML(19) PDF(9)
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Unreasonable application of nitrogen fertilizer leads to resource waste and affects the normal growth, development, yield, and quality of peanuts. The study aimed to investigate the impact of varying nitrogen application rates on the yield, quality, nitrogen accumulation dynamics, physiological characteristics to light and temperature, and root morphology of summer peanuts. The findings aim to offer insights for the efficient and scientific application of nitrogen fertilizers in peanuts. A field experiment on nitrogen fertilizer application was conducted in Wen County, Jiaozuo City, Henan Province, from 2021 to 2022. The tested variety was ‘Yuhua 22’ with five nitrogen fertilizer treatments of 0, 45, 90, 135, and 180 kg·hm−2. The study assessed the yield and quality indicators of summer peanut pods, at the mature stage, and the soil-plant analysis development (SPAD) value, canopy photosynthetic effective radiation, and canopy temperature were conducted at various stages namely the seedling, flowering-pegging, pod-setting, and pod-filling stages. Plant samples were collected to analyze nitrogen accumulation and root morphology. With an increasing nitrogen application rate, the peanut pod yield could be fitted by “linear + platform trends” in both years, with suitable nitrogen application rates of 150 and 113 kg·hm−2, respectively. Nitrogen application increased the yield by an average of 18.86%. The crude protein, oil, and amino acid contents in grain at maturity first increased and then stabilized with an increasing nitrogen application rate. Compared to zero nitrogen application, the application of nitrogen led to notable effects, with average increases of 7.51%, 3.10%, and 10.08%, in crude protein, oil, and amino acid contents in grains respectively. The nitrogen accumulation amount of summer peanuts was fitted using nonlinear regression using a logistic equation. It was concluded that nitrogen application could increase the maximum and average accumulation rates, accelerate the rapid accumulation period, and promote the occurrence of peak absorption, thereby increasing the maximum nitrogen accumulation in peanuts and promoting sustainable and rapid growth of summer peanuts. The maximum, minimum, and mean canopy temperatures at each growth stage firstly decreased then increased with increasing nitrogen application rate; the SPAD value of peanut leaves and the photosynthetic active radiation and components of the canopy significantly increased with nitrogen application at 135 kg·hm−2. The total root length, total root surface area, total root volume, and average root diameter of peanuts increased by 41.03%, 22.36%, 38.71%, and 12.19% at each growth stage after nitrogen application. The nitrogen fertilizer utilization efficiency was the highest under the nitrogen application rate of 135 kg·hm−2. Meanwhile, increasing the nitrogen application rate gradually decreased agricultural efficiency and partial productivity. Reasonable nitrogen application can significantly increase the yield and quality of summer peanuts, promote nitrogen accumulation and utilization, and improve the physiological performance of light and temperature during growth. The recommended nitrogen application rate for summer peanuts under this test condition is 110−150 kg·hm−2.
Effects of tillage measures and organic manure on soil heavy metal pollution in dryland wheat fields
YANG Na, WANG Ke, YANG Zhiguo, ZHANG Jiancheng, WEN Yunjie, XI Jilong
 doi: 10.12357/cjea.20230431
Abstract(87) HTML(62) PDF(8)
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Heavy metal pollution in agricultural soils is a crucial environmental problem. In this study, we investigated the effects of different tillage measures and organic fertilizers on the accumulation of heavy metals in dryland wheat fields and their ecological efficiency based on a long-term tillage and fertilizer experiment (since 2007) with wheat cultivation. Four treatments were applied: deep tillage + chemical fertilizer (T), deep tillage + chicken manure + chemical fertilizer (TM), no tillage + chemical fertilizer (NT), and no tillage + chicken manure + chemical fertilizer (NTM). The effects of these treatments on the physicochemical properties of soil at 0–20 cm depth (pH, electric conductivity, organic matter content, and total nitrogen content) and heavy metals (Pb, Cd, As, Hg, Cr, Cu, Zn, and Ni) contents were investigated. The heavy metal geoaccumulation index and potential ecological risk indice were used to evaluate heavy metal pollution and ecological risk. The results showed that TM, NT, and NTM treatments significantly decreased soil pH by 1.10% to 2.56% and increased soil electric conductivity by 6.19% to 57.08% compared to T. Soil organic matter content increased by 33.22% in NTM treatment compared to that in T treatment. The application of chicken manure significantly affected soil heavy metals contents. The total Hg content of soil was significantly increased by 123.60% and 150.56% in TM and NTM treatments compared with that in T treatment, and the available Cu, Zn, and Cd contents increased significantly by 16.89% to 23.48%, 219.04% to 520.99%, and 2.90% to 20.29%, respectively. The tillage measure also had a significant effect on soil heavy metals contents. Compared to those under TM treatment, the contents of total Hg, total Zn, available Cu, available Zn, and available Cd showed significant increases of 12.06%, 8.11%, 5.64%, 94.65%, and 16.90% under NTM treatment, respectively; whereas the contents of total Pb, available Pb, and total Cr contents significantly reduced by 63.74%, 70.00%, and 3.14%, respectively. The Hg content showed the highest potential ecological risk index of all treatments, expressed as T (32.36) < NT (41.45) < TM (72.36) < NTM (81.09). Other heavy metals were at a low level, with the comprehensive potential ecological risk pollution index expressed as T (79.05) < NT (82.33) < TM (115.27) < NTM (120.00). In summary, long-term no-tillage and chicken manure application significantly decreased pH; increased electric conductivity, contents of organic matter and total nitrogen; and increased Cu, Zn, and Cd availability. The individual and potential ecological risk indices for Hg pollution were at the moderate to strong level when treated with chicken manure, whereas the other heavy metals were at a light level. Moreover, the composite and potential ecological risk indices differed slightly, indicating the requirement to strengthen the safe application of organic fertilizers.
Control effect and mechanism of ginger essential oil and citral on ginger Fusarium wilt
ZHOU Lirong, XIONG Shijie, ZHANG Lingling, MA Huihui, ZHU Xuedong, YIN Junliang, LIU Yiqing
 doi: 10.12357/cjea.20230230
Abstract(94) HTML(59) PDF(10)
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Fusarium wilt in ginger plants is primarily caused by Fusarium oxysporum, and it is extremely difficult to control. Chemical agents are effective for controlling Fusarium wilt. To investigate environmentally friendly and safe plant-derived biopesticides, this study evaluated the inhibitory effects of ginger essential oil (GEO) and citral on F. oxysporum FOX-1 using the mycelium growth rate and spore germination methods. The mycelial growth rate method was used to determine the inhibitory effects of various GEO and citral concentrations on F. oxysporum FOX-1 mycelial growth. The lowest concentrations of GEO and citral that effectively prevented mycelial growth on potato dextrose agar (PDA) plate after 48 h were recorded as the minimum inhibitory concentrations (MICs). The spore germination method was used to assess the effects of GEO and citral at different concentrations (0, 1/2 MIC, MIC) on the spore number and germination of F. oxysporum FOX-1, respectively. Scanning electron microscopy (SEM) was used to observe the mycelial morphology of F. oxysporum FOX-1, and propidium iodide (PI) staining was used to assess cell membrane damage. Furthermore, the effects of GEO and citral on the cell integrity and permeability of F. oxysporum FOX-1 were evaluated by measuring the changes in relative electrical conductivity, proteins, nucleic acids, malondialdehyde, and ergosterol. The effects of MIC GEO and citral on controlling Fusarium wilt in ginger in a pot experiment were determined 15 d after inoculation with F. oxysporum FOX-1. The results indicated that 2 g∙L−1 GEO and 0.5 g∙L−1 citral significantly inhibited the mycelial growth of F. oxysporum FOX-1, with EC50 values of 1.102 g∙L−1 and 0.141 g∙L−1 for GEO and citral, respectively. This indicates that both GEO and citral exhibited dose-dependent effects, with MIC values of 2 g∙L−1 and 0.5 g∙L−1, respectively. In addition, these treatments of 1/2MIC and MIC significantly inhibited the germination of F. oxysporum FOX-1 spores compared to the control (CK). Compared with CK, the 1/2MIC and MIC GEO treatments reduced the number of F. oxysporum FOX-1 spores by 35.6% and 59.3%, respectively. Similarly, the 1/2MIC and MIC citral treatments reduced the number of F. oxysporum FOX-1 spores by 61.0% and 78.0%, respectively. After 12 h of treatment, the germination rates of F. oxysporum FOX-1 spores in the 1/2MIC and MIC GEO treatments reduced by 20.4% and 34.7%, whereas the germination rates in the 1/2MIC and MIC citral treatments decreased by 86.1% and 95.0%, respectively. After 3 d of GEO and citral treatment, the SEM results showed that the cell walls and cell membranes of F. oxysporum FOX-1 were damaged and could not maintain the normal linear morphology of the mycelium. They also showed different degrees of curvature, folds, and depressions. Furthermore, the PI staining revealed that the GEO and citral treatments severely damaged the integrity and permeability of the cell membrane of F. oxysporum FOX-1, resulting in a significant increase in the number of spores. Moreover, this treatment resulted in a sharp increase in cytoplasmic loss, extracellular conductivity, and protein, nucleic acid and malondialdehyde contents in the damaged F. oxysporum FOX-1 cells. After 3 d of treating the mycelium, high concentrations of GEO (2 g∙L−1) and eugenol (2 g∙L−1) reduced the ergosterol content of F. oxysporum FOX-1 by 27.0% and 45.2%, respectively, when compared with CK. GEO and citral treatments also weakened the pathogenicity of F. oxysporum FOX-1. Moreover, after 15 d of inoculation with F. oxysporum FOX-1, the 2 g∙L−1 GEO and 0.5 g∙L−1 citral treatments exhibited efficacy rates of 32.7% and 42.3%, respectively. The 0.5 g∙L−1 citral treatments was not significantly different from that of the positive control, chlorothalonil, which exhibited an efficacy rate of 47.1%. In summary, GEO and citral had significant inhibitory effects on the growth of F. oxysporum FOX-1 and could control Fusamum wilt in gingers. These findings could lay the foundation for the development of botanical antifungal agents for the management of Fusamum wilt.
Effects of biogas slurry combined with chemical fertilizer on Allium fistulosum yields, soil nutrients, microorganisms, and enzymes activities
WEN Yunjie, ZHANG Jitao, LI Lin, WANG Qi, DIAO Fengwei, GAO Min, WANG Xiuhong, SHI Xiangyuan
 doi: 10.12357/cjea.20230401
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The study aimed to determine the optimal ratio of biogas slurry to chemical fertilizer and the effects of biogas slurry combined with chemical fertilizer on Allium fistulosum yields, soil nutrients levels, microorganism contents, and enzyme activities. The field experiment comprised six treatments: no fertilization (CK), chemical fertilizer (CF), 25% substitution inorganic N by biogas slurry N (25BS), 50% substitution inorganic N by biogas slurry N (50BS), 75% substitution inorganic N by biogas slurry N (75BS), and 100% substitution inorganic N by biogas slurry N (100BS). A. fistulosum yields, soil nutrients contents, phospholipid fatty acids (PLFA) contents, and activities of enzymes involved in C, N, and P cycling were investigated. Using the partial least squares path model (PLS-PM), the variations in these parameters to elucidate their internal correlations were explored. The results indicated that CF and biogas slurry (25BS, 50BS, 75BS, and 100BS) treatments significantly increased A. fistulosum yield compared to CK (P<0.05), with increases of 37.2%, 75.9%, 118.9%, 99.8%, and 59.3%, respectively. Furthermore, as the substitution percentage of inorganic N by biogas slurry N increased, the yields showed a tendency of increasing initially and then decreasing, with the highest yield of 59.9 t·km−2 observed for the 50BS treatment. The application of biogas slurry was effective in improving soil nutrients contents. Compared to CK, the biogas slurry significantly increased the contents of soil organic carbon (SOC), total nitrogen (TN), ammoniacal nitrogen (NH4+), nitrate nitrogen (NO3), available phosphorus (AP), and available potassium by 19.5%–65.8%, 40.5%–69.6%, 26.8%–77.4%, 30.1%–41.9%, 10.5%–40.6%, and 5.4%–8.5%, respectively. The application of biogas slurry resulted in a notable enhancement in soil microbial contents and enzymes activities. Compared to CK, the biogas slurry significantly increased the PLFA contents of bacteria, fungi, and actinomycetes (P<0.05), while concurrently reducing the ratio of gram-positive to gram-negative bacteria. This shift is advantageous for improving the activities of enzymes involved in C, N, and P cycling. However, with an increasing ratio of inorganic N substitution by biogas slurry, the number of bacteria, gram-positive bacteria, fungi, total PLFA content, and enzymes activities involved in C, N, and P cycling exhibited an initial increase followed by a subsequent decrease. The results of PLS-PM indicated that the observed increase in A. fistulosum yields after biogas slurry application could be attributed to the improvements in SOC, TN, NH4+, NO3 and AP contents, microbial contents, and the enhanced activities of enzymes involved in N cycling. Nevertheless, the excessive application of biogas slurry led to elevated soil electrical conductivity (EC), which inhibited microbial activities and ultimately reduced A. fistulosum yields. In conclusion, this study illustrated that the temporary utilization of biogas slurry contributed to the enhancement of A. fistulosum yields, effective improvement of soil nutrient levels, and promotion of soil microbial contents and enzymes activities. Notably, the optimal substitution percentage of inorganic N by biogas slurry was 50% to achieve the highest improvement. However, biogas slurry cannot completely substitute chemical fertilizers because its excessive use may lead to an increase in soil salinity, adversely affecting the growth of A. fistulosum and microorganisms.
Spatial-temporal variation and influencing factors of farmland ecological value in the Yangtze River Economic Belt
WANG Jianxin, LUO Xiaofeng, LIU Zaizhou, TANG Lin
 doi: 10.12357/cjea.20230515
Abstract(32) HTML(11) PDF(9)
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Farmland ecosystems perform economic, ecological, and social functions and are closely related to agricultural and rural ecology. To investigate the spatial and temporal dynamic changes in farmland ecological value and their influencing factors in the Yangtze River Economic Belt from 2010 to 2021, we developed an indicator system for assessing farmland ecological value. This system was based on an improved ecosystem service valuation model and ecosystem energetic value analysis framework and analyzed it using the spatial Durbin model. Based on the above analysis, the results showed that: 1) from 2010 to 2021, the average level of farmland ecological value in the Yangtze River Economic Belt showed a fluctuating growth trend with regional differences, and the average value ranging from 0.381 to 0.435. The fluctuation range of farmland ecological value of upstream, midstream, and downstream regions were 0.458−0.607, 0.321−0.433 and 0.247−0.349, respectively, and the fluctuation range of each region was relatively stable. There were significant differences in the growth contribution of the farmland ecological value among the provinces. The growth contribution was mainly concentrated in the upstream region, whereas the middle and downstream regions experienced negative growth. 2) From the perspective of spatial and temporal variation, the farmland ecological value in the Yangtze River Economic Belt displayed a gradient-decreasing trend of “upstream, midstream, downstream” and the high-level areas presented continuous spatial agglomeration. The overall spatial distribution characteristics were “high in the west and low in the east” and the spatial differentiation and aggregation characteristics were significant. 3) Multiple factors affect the ecological value of farmland in the Yangtze River Economic Belt. The results showed that financial and political support for agriculture, the urbanization rate of population, crop planting structure, and average annual precipitation contributed to improving farmland ecological value, among which the urbanization rate of population could significantly improve the farmland ecological value of neighboring areas. In contrast, the level of agricultural economic development and the urban-rural income gap were not conducive to improving and enhancing farmland ecological value. Therefore, based on the research findings, the following recommendations are proposed for the Yangtze River Economic Belt: Green, ecological, and sustainable agricultural policies should be formulated to realize the value of agroecological products, considering their locational advantages. This study focused on improving the utilization efficiency of water, soil, light, heat, and other resources in the regional farmland ecosystem and improving the level of agricultural mechanization, intelligent development, and field management. It should strengthen financial and political support for agriculture, the development of new urbanization and the brand building of regional agricultural products, the construction of agricultural infrastructure, the cultivation of professional farmers, and the formation of a market mechanism of “high quality and high price” for ecological agricultural products. It should establish a trading platform for agroecological products, promote the transformation of ecological value into ecological well-being, and gradually promote the proposal and improvement of mechanisms for realizing the value of agroecological products in the Yangtze River Economic Belt.
Reasons for promoting rhizosphere nutrient absorption and utilization of Atractylodes lancea by intercropping with maize
CAO Meiyu, ZHANG You, YAN Binbin, WAN Xiufu, SUN Kai, KANG Chuanzhi, WANG Hongyang, LYU Chaogeng, ZHANG Yan, GUO Lanping
 doi: 10.12357/cjea.20230361
Abstract(48) HTML(36) PDF(3)
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Previous studies have found that intercropping with maize can alleviate the continuous cropping obstacle of Atractylodes lancea, and the change of nutrient conditions is one of the key factors. In order to explore the effect of A. lancea-maize intercropping on nutrient absorption and utilization in the rhizosphere of A. lancea, a two-year field experiment of different rhizosphere separation treatments in the A. lancea-maize intercropping was carried out. Four treatments were set up, which were A. lancea monoculture (A), A. lancea-maize intercropping without separation (AI), A. lancea-maize intercropping with nylon separation (AN) and A. lancea-maize intercropping with plastic film (AP). The biomass of A. lancea and the contents of four volatile oil components were measured at harvest. The contents of nitrogen, phosphorus and potassium in the rhizome of A. lancea, rhizosphere soil pH, organic matter and soil nutrient factors were compared and analyzed. The results showed that the fresh weight of rhizomes of A. lancea of AI treatment was significantly higher than those of A and AP treatments (P<0.05), which was 21.5% and 69.1% higher, respectively; while AN treatment was 10.7% and 54.2% higher than AI and AP, respectively. The content of β-eudesmol of AI treatment was significantly higher than that of A and AP treatments by 128.4% and 205.6%, respectively (P<0.05). The content of atractylodin of AI treatment was significantly higher than that in A and AP treatments by 875.0% and 97.7%, respectively; and that of AN treatment was significantly higher than that of A and AP treatments by 764.0% and 75.0%, respectively. The total content of four volatile oil components A. lancea of AI and AN treatment was significantly higher than that of A and AP treatments by 82.8%−210.3% (P<0.05), indicating that the underground rhizosphere interaction of A. lancea-maize intercropping played an important role in promoting the biomass and volatile oil accumulation of A. lancea rhizome. Compared with A and AP treatments, AI and AN treatments decreased the rhizosphere soil pH of A. lancea by 0.4%−6.3%, and the soil organic matter increased by 13.5%−48.1%; while AI treatment significantly increased alkali-hydrolyzable nitrogen content by 32.8% and 36.2%, respectively; AN treatment significantly increased available potassium content by 51.5% and 46.7%, available phosphorus content by 78.3% and 86.6%, respectively. It shows that the rhizosphere interaction of A. lancea and maize improve the rhizosphere acidification level of A. lancea and activate soil nitrogen, phosphorus and potassium compared with no rhizosphere interaction. Correlation analysis showed that atractylon was mainly positively correlated with nitrogen, phosphorus and potassium in rhizome of A. lancea; and nitrogen, phosphorus and potassium in rhizosphere soil; while atractylodin was mainly positively correlated with potassium in rhizome. Compared with A and AP treatments, AI treatment increased the phosphorus absorption efficiency of A. lancea by 23.4% and 30.0%, respectively. The nitrogen and potassium utilization efficiency was significantly increased by 131.3%−222.2% (P<0.05)under AI and AN treatments compared with A, indicating that the rhizosphere interaction of intercropping crops promote the phosphorus absorption, and improve the nitrogen and potassium nutrient utilization ability of A. lancea. In conclusion, in the A. lancea-maize intercropping system, the underground rhizosphere interaction (under AI and AN treatment) promoted the absorption and utilization of nutrients in the rhizomes of A. lancea compared with no rhizosphere interaction (under A and AP treatment), thereby increasing the yield of A. lancea and affecting the accumulation of volatile oil in the rhizomes of A. lancea. This study reveals that the underground rhizosphere interaction of A. lancea-maize intercropping is an important factor to promote the absorption and utilization of nutrients of A. lancea, and provides an important reference for the promotion of the ecological diversity planting mode of medicinal plants.
Climatic suitability regionalization of Furong plums based on GIS in Fujian Province
WU Li, DU Xiaojie, SUN Chaofeng, HUANG Chuanrong, WANG Jiayi, CHEN Jiajin, LIN Huiyang
 doi: 10.12357/cjea.20230415
Abstract(70) HTML(36) PDF(9)
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Fujian is located on the southeast coast of China, where superior climatic resources create conditions for the cultivation of Furong plums. However, the topography of Fujian is complex, the climate is changeable, and meteorological disasters in Fujian are of many different types and characterized by wide distribution, high frequency, high intensity, and heavy losses, which affect the yield and quality of Furong plums. To reasonably utilize climatic resources and scientifically plan the planting layout of Furong plums, climatic suitability regionalization of Furong plums in Fujian was conducted using GIS and based on meteorological data from 1971 to 2018 from 67 ground meteorological stations, area and yield data from 2005 to 2014 of Furong plums, and geographical information data. Based on the climatic characteristics of Fujian and the growing environmental conditions of the Furong plums, an indicator system for the climatic suitability regionalization of the Furong plums was established. The weights of the regionalization indicators were calculated using the analytic hierarchy process and the entropy weight method. Geographical reckoning models between the regionalization indicators, longitude, latitude, and altitude were established using multivariate linear regression analysis. The climatic suitability index of the Furong plums was calculated using the weighted summation method. The climatic suitability areas of Furong plums in Fujian were divided into suitable, sub-suitable, and unsuitable areas based on the distribution laws of the climatic suitability index, the actual conditions of growth and field investigation of Furong plums in Fujian, and the regionalization result of the regionalization indicator for limiting the growth of Furong plums. Finally, the regionalization results were verified based on the planting status of Furong plums and the per-unit area yield of the plums. The results of this study were as follows: Suitable areas were mainly distributed in the middle- and high-altitude areas of north of Longyan and Fuzhou, and most of Ningde, Sanming, and Nanping. The sub-suitable areas were mainly distributed in the middle of Fujian along Wuping and Zhangping to Luoyuan. The unsuitable areas were mainly concentrated in the low-altitude areas along the south and southeast coasts and the high-altitude areas of the northern mountain regions. The regionalization results were in good agreement with the planting status of Furong plums and the per-unit area yield of plums. The results of this study provide a decision reference for the planting of Furong plums in Fujian.
Effects of conservation tillage methods on maize growth and yields in a typical black soil region
LI Ruiping, XIE Ruizhi, LUO Yang, SUI Pengxiang, ZHENG Hongbing, MING Bo, WANG Hao, LIU Wuren, ZHENG Jinyu, LI Shaokun
 doi: 10.12357/cjea.20230346
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Implementation of conservation tillage is crucial for protecting black soil in Northeast China and ensuring national food security. A three-year field experiment was conducted to examine the impact of conservation tillage on maize yields and its key factors in a typical black soil region of Northeast China. Four treatments were designed, including conventional ridge tillage without straw mulching (CK), no-tillage with 100% crushed straw mulching (T1), no-tillage with high stubble and 100% straw mulching (T2), and reduced tillage with 100% straw strip mulching (T3). This study analyzed the physical and chemical properties of soil, maize growth, yields, and its components to assess the effects of different treatments on soil and maize yields. The results demonstrated that conservation tillage treatments (T1, T2, and T3) increased soil organic matter content in the 0–20 cm soil layer compared with the CK treatment. Additionally, conservation tillage significantly improved the soil water content during the sowing to seedling stages, while decreasing the soil temperature. T1, T2, and T3 treatments led to increases in the soil water content, ranging from 7.8% to 30.4 %, 9.0% to 18.7%, and 17.3% to 20.0%, respectively. Meanwhile, the soil temperature decreased by 2.56 °C to 3.11 °C, 2.02 °C to 2.27 °C, and 0.94 °C to 1.93 °C, respectively. The data revealed that the emergence times of T1 and T2 were delayed by 5–7 days and 4–6 days, respectively. However, T3 only experienced a delay of two days. Over the three years, the average seedling emergence rate of T3 treatment increased by 3.2% compared to CK, whereas the emergence rates of T1 and T2 decreased by 4.3% and 4.7%, respectively. T1, T2, and T3 treatments reduced the uniformity of plant height and dry matter accumulation at the sixth leaf collar stage, with T3 treatment exhibiting a significantly smaller decrease than the T1 and T2 treatments. Additionally, dry matter accumulation after the sixth leaf collar gradually decreased in T3 compared to that in the other treatments. T1 and T2 significantly reduced the yield by 7.5% to 15.6% and 5.5% to 12.9%, respectively, over the course of three years. However, T3 treatment did not show a significant difference compared with CK. The structural equation model (SEM) indicated that conservation tillage indirectly affected yields by regulating soil water content and temperature, thereby influencing emergence time, emergence rate, ear number, and 100-kernal weight. Furthermore, conservation tillage can directly affect emergence quality and yield components, subsequently affecting yields. Therefore, T3 is an optimal conservation tillage practice for a typical black soil region of Northeast China. T3 not only improves soil organic matter content but also helps in adjusting the contradiction between soil moisture and temperature to shorten the emergence time, improve the quality of emergence, and stabilize yields.
Wind disaster risk assessment for facility agriculture in Shandong Province
TAN Fangying, WANG Jianlin, ZHANG Lei, LI Feng, ZHANG Jibo, ZHAO Xiaofeng
 doi: 10.12357/cjea.20230258
Abstract(85) HTML(40) PDF(9)
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Wind disasters are meteorological disasters that have a significant impact on China’s facility agricultural production, and it is of great theoretical and practical significance to conduct research on wind disaster risk assessment for effective disaster prevention and mitigation in facility agriculture. This study explored a wind risk assessment method for facility agriculture based on natural disaster risk theory and its application in Shandong Province. Using extreme wind speed observation data of Shandong Province from 1991 to 2020, the fuzzy information distribution theory was used to calculate the probability of wind disaster occurrence at each level, and the hazard index of wind disasters was constructed by combining it with wind intensity. Based on GF-6 satellite image for 2020, an exposure index was constructed by extracting the areas of agricultural facilities in each district and county. Based on the wind resistance design standards of agricultural facilities, a vulnerability index was constructed using the maximum wind speed data. Based on wind damage information and wind speed observation data from 2010 to 2020, a hazard index of wind disaster was constructed to assess disaster prevention and mitigation capabilities. These four risk assessment elements were integrated to construct a wind-damage risk-assessment index for facility agriculture. The analysis results showed that wind hazard was influenced by topography and geomorphology, with the highest hazard in the central mountainous area and Shandong Peninsula. The distribution of high exposure areas was in line with the norms for land used for facility cultivation, and was mainly concentrated in the eastern part of central, northwestern, and southwestern Shandong. The distribution of vulnerability was essentially opposite to basic wind pressure, and medium-high value areas were mainly distributed in southern Shandong and the eastern parts of central Shandong, where plastic greenhouses and medium-sized arched plastic greenhouse were more concentrated. Areas with weaker capacity of disaster prevention and mitigation were mainly distributed in northwestern Shandong, southwestern Shandong, and western part of central Shandong, where disaster index was higher, the wind disaster warning capacity was weaker and the economy was less developed. The risk of wind disasters in facility agriculture was determined by integrating four factors: hazard, exposure, vulnerability, and capacity of disaster prevention and mitigation. The high-risk areas for wind disasters in facility agriculture were mainly in northwestern Shandong, where exposure was high; southwestern Shandong, where the vulnerability was high and capacity of disaster prevention and mitigation was weak; and central Shandong, where exposure and hazard were high and capacity of disaster prevention and mitigation was weak. The results of the wind disaster risk assessment in Shandong Province showed that the wind disaster risk index and the occurrence of wind disasters in each district and county were significantly consistent in space. The wind disaster risk assessment index for agricultural facilities constructed based on the natural disaster risk theory was reasonable and feasible, providing a reference for the scientific management of wind disaster risk and effective disaster prevention and mitigation in facility agriculture.
Spatial-temporal differentiation characteristics and key driving factors of agricultural carbon emissions in the three northeastern provinces of China
QIAN Fengkui, WANG Xiangguo, GU Hanlong, WANG Dapeng, LI Pengfei
 doi: 10.12357/cjea.20230225
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Climate change caused by increasing carbon dioxide emissions is one of the major challenges today. Promoting the development of low-carbon agriculture is an effective way to deal with climate threats and agricultural nonpoint source pollution. Accurately measuring the effect of agricultural carbon emissions and its spatial and temporal evolution characteristics is the basis for promoting the development of low-carbon of agriculture, and studying the key driving factors of agricultural carbon emissions and the trade-off and coordination relationship between driving factors is of great significance for formulating regional carbon emission reduction policies in Northeast China. Based on the input data of agricultural materials and the IPCC method, this study calculated the agricultural carbon emissions of three provinces in Northeast China from 2000 to 2019, used the spatial autocorrelation analysis method to clarify the spatial and temporal differentiation characteristics of agricultural carbon emissions, and explored the driving factors of agricultural carbon emissions and their interactions through the LMDI decomposition model and geographic detector. The results showed the following: 1) The total carbon emissions of the three provinces in Northeast China showed a trend of increasing and then decreasing. The incremental changes in carbon emissions can be divided into three stages: the fluctuating rising period (2000–2009), transitional period (2010–2015), and steady decline period (2016–2019). In 2015, the total amount of agricultural carbon emissions reached a peak of 17.5966 million t, an increase of 67.88% compared to that in 2000, with an average annual increase of 4.53%. During the study period, all carbon sources showed different degrees of growth, and chemical fertilizer application was the main carbon source, accounting for 75.12%. 2) The spatial distribution of the total carbon emissions in the three northeastern provinces had a significant spatial autocorrelation. The hotspots of carbon emissions were mainly distributed in the northeastern plain area, and it showed agglomeration trend and scope were expanding. The cold spots of carbon emissions were mainly distributed in the Changbai and Daxing’an Mountains and did not change significantly over time. 3) Total agricultural carbon emissions in the three northeastern provinces were affected by several factors. The improvement of agricultural production efficiency, the optimization of agricultural industrial structure, and the reduction of agricultural labor force had an inhibitory effect on carbon emissions, and the proportions of carbon emissions reduction were 207.31%, 21.56%, and 20.72%, while the level of agricultural economic development had a strong driving effect on carbon emissions, achieving a 349.59% carbon increment. The interaction between the levels of agricultural economic development, agricultural production efficiency, and agricultural structure is more nonlinear than the influence of a single factor on carbon emissions. The superposition of the labor force scale and other factors shows the effect of two-factor enhancement. The research results revealed that the carbon emission effect of the three northeastern provinces was easily affected by the surrounding areas, and the degree of influence increased. Simultaneously, there was a strong synergy between the driving factors of carbon emissions.
Sensitivity analysis and optimization of leaf area index related parameters of dryland wheat based on APSIM model
WEI Xuehou, NIE Zhigang
 doi: 10.12357/cjea.20230345
Abstract(163) HTML(77) PDF(12)
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Crop growth model parameterization is characterized by a large number of parameters and the low efficiency of parameterization. To determine the rate of crop model parameters quickly and efficiently, the promotion of rapid application of crop models in localization is required. In this study, we used a combination of sensitivity analysis and intelligent optimization algorithm to adjust the parameters of the crop model. We used the experimental data (leaf area index) of dryland wheat in large fields in Mazichuan Village, Lijiabao Town from 2002 to 2004, and Anjiagou Village, Fengxiang Town from 2015 to 2017 in Anding District, Dingxi City, Gansu Province as references. Using the extended Fourier amplitude sensitivity test method, a sensitivity analysis of 23 parameters of the APSIM-Wheat dryland wheat leaf growth sub-model was performed using SimLab software, and the sensitivity coefficients of each parameter to the model results were obtained. On this basis, the parameters with a larger first-order sensitivity index and global sensitivity index were selected as the optimization parameters, and R programming was used to construct the algorithmic fitness function, implement the particle swarm optimization algorithm, and run the APSIM-Wheat model to optimize the parameters automatically. We performed this to ensure fast and effective determination of the model parameters. The results showed that :1) the six parameters most sensitive to the leaf growth model of dryland wheat were, in descending order, maximum specific leaf area at a leaf area index of 0, nitrogen limiting factors in leaf growth, accumulated temperature from seedling to jointing, extinction coefficient, accumulated temperature from jointing to flowering, and transpiration efficiency coefficient; 2) optimization of the parameters in the leaf growth submodel for dryland wheat resulted in a maximum specific at a leaf area index of 0 was 26 652 mm2∙g−1 , a nitrogen limiting factor in leaf growth was 0.96, an accumulated temperature from seedling to jointing was 382 ℃·d, an extinction coefficient was 0.44, an accumulated temperature from jointing to flowering was 542 ℃·d, and a transpiration efficiency coefficient was 0.0056; 3) after the optimization of the aforementioned parameters, the mean value of the root mean square error between the measured and simulated values of the leaf area index decreased from 0.080 to 0.042. The mean value of the normalized root mean square error decreased from 11.54% to 6.11%, and the mean value of the model validity index increased from 0.962 to 0.988, indicating that the simulation of the leaf area index was better after the optimization. When compared with the traditional manual trial-and-error method, this method avoids the uncertainty of the optimization parameters, quickly and efficiently identifies the important parameters of the model, realizes automatic parameter rate fixing, improves the efficiency of model parameter rate fixing, alleviates the problem of many parameters and low efficiency in the process of model rate fixing, and finally, enables the model to be applied locally faster so that it can better guide the agricultural production. The methodology of this study is also instructive for the parameter tuning optimization of other crop modules in the APSIM-Wheat model.
Effects of quorum sensing and quorum quenching mediated by AHLs on plant-rhizosphere microbial interactions
ZHANG Qingxu, LI Jianjuan, GUO Yue, WANG Yanyan, PENG Yanhui, WANG Yuhua, HU Mingyue, LIN Wenxiong, WU Zeyan
 doi: 10.12357/cjea.20230414
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The rhizosphere is a unique environment that arises from the interaction between plant roots and soil microorganisms. The metagenome of the microbial community in the rhizosphere plays a crucial role in shaping the plant microbiome. The interaction between plants and rhizosphere microorganisms is a complex process. In the rhizosphere environment, the microbial community recruits specific microorganisms through intricate signaling mechanisms within and between species. This coordination and control of the mixed community ultimately impacts the growth, development and health of plants. From an academic perspective, rhizosphere signaling mechanisms can be categorized into three primary types. Firstly, plants transmit signals to microorganisms by secreting low molecular weight molecules. Secondly, there is inter- and intraspecific microbial signaling. Lastly, microorganisms transmit signals to plants through compounds they produce. Rhizosphere microbes utilize quorum sensing (QS) to autonomously generate and release distinct signaling molecules, enabling them to detect variations in their concentrations and thereby regulate microbial quorum behavior. QS is a bacterial intercellular communication mechanism that regulates the expression of numerous bacterial genes, which are involved in various plant-microbe interactions. These interactions encompass functions such as biofilm formation, nitrogen fixation, hydrolysis, enzyme and extracellular polysaccharide synthesis, toxin production, cell movement, and intercellular connectivity. QS systems are characterized by the synthesis and release of specific signaling molecules. This process is crucial in rhizosphere communication as it enables the transmission of inter- and intraspecific information through the necessary signaling molecules. Due to the high density and diversity of rhizosphere bacteria, the rhizosphere may facilitate the transmission of QS signals. Additionally, these signaling molecules aid in the colonization of plant root surfaces or other rhizosphere-related areas by rhizosphere bacteria through gene expression mediated by QS. Recent research has revealed the presence of N-acyl-homoserine lactones (AHLs), diketopiperazines, diffusible signaling factor, secondary metabolites, phytohormonelike molecules and other QS signaling molecules in rhizosphere soil bacteria. AHLs are the most extensively studied quorum sensing signaling molecules in bacteria. They not only mediate bacterial quorum sensing, but also have a significant impact on the interaction between plants and rhizosphere microorganisms. This includes the colonization of rhizosphere microorganisms, the maintenance of soil ecosystems and the effects on plant growth. An in-depth understanding of the quorum sensing mechanism mediated by AHLs holds significant importance in promoting agricultural production, enhancing plant health, and fostering sustainable development. This article presents a review of the quorum sensing mechanism mediated by AHLs and discusses the regulatory role of AHLs in the interaction between plants and rhizosphere microorganisms. It explores the beneficial effects of AHLs on plant growth and development, stress tolerance and disease resistance, as well as the harmful effects of rhizosphere pathogenic bacteria on plants due to AHLs-mediated regulation of the QS system. Additionally, the article explores the impact of AHLs-based quorum quenching on plant-rhizosphere microbial interactions, aiming to provide valuable insights for plant health and agricultural production. The article also proposes new ideas and methods to promote the development of sustainable agriculture.
Response of arbuscular mycorrhiza fungi to long-term organic and inorganic fertilization in agricultural soils in dry farming regions
TIAN Xia, WANG Yuan, ZHANG Yu, GUO Rong, MA Kun
 doi: 10.12357/cjea.20230304
Abstract(75) HTML(52) PDF(14)
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The dynamics of arbuscular mycorrhiza (AM) fungal communities are important for effective, long-term soil ecosystem management. To reveal the response mechanisms of soil AM fungi to long-term combined applicatoin of organic and inorganic fertilizers in dryland farming regions, the effects of no fertilizer application (T0), long-term chemical fertilizer application (T1), long-term combined applicatoin of chemical fertilizer and cow manure organic fertilizer (T2), and long-term combined applicatoin of chemical fertilizer and sheep manure organic fertilizer (T3) on soil were investigated using a one-way randomized group design based on 11 consecutive years of locality testing and high-throughput sequencing methods. Differences in the composition and diversity of soil AM fungal communities were compared, and the factors affecting the soil environment and interaction effects that drive changes in soil AM fungal community composition and diversity were investigated. The results indicated that the soil total nitrogen and organic matter contents significantly increased, whereas the pH significantly decreased (P<0.05) under the T2 and T3 treatments compared to those under T0. Furthermore, compared with eight years of fertilization, 11 years of fertilization significantly decreased the total phosphorus and available potassium contents of the soil in the T0, T1, and T3 treatments. The dominant genera of soil AM fungi under organic and inorganic fertilization were Glomus and Paraglomus, respectively. However, the relative abundance of Claroideoglomus decreased significantly and changed from dominant to non-dominant. In contrast, the relative abundance of Claroideoglomus was more susceptible to long-term fertilization than that of Glomus and Paraglomus. After a period of eight years of combined applicaiton of organic and inorganic fertilizers, the relative abundance of AM fungi, specifically Claroideoglomus and Ambispora, in soils under T2 and T3 treatments was significantly different from that of T0 (P<0.05). Over the 11-years fertilization period, the relative abundances of Claroideoglomus and Ambispora under T2 and T3 treatments were not significantly different from those under T0. With the extension of fertilization time, differences in the α diversity of soil AM fungal communities disappeared between treatments. NMDS analysis showed that long-term fertilization changed the β diversity of the soil AM fungal community, but the soil AM fungal community was more similar between the T2 and T3 treatments. During the continuous application of fertilizer, significant changes were observed in the structural composition and diversity of the soil AM fungal community. Moreover, the soil environmental factors influencing changes in the AM fungal community shifted from soil total nitrogen and pH to soil total phosphorus. Long-term combined applicatoin of organic and inorganic fertilizers did not simultaneously improve the main physicochemical properties of soil, such as total phosphorus and available potassium. As the number of years of fertilization increased, the soil factors that drove changes in the structure and diversity of the soil AM fungal communities were significantly altered. The AM fungal community is more easily influenced by sensitive driving factors with changes in all soil environments.
Can the adoption of ecological farming and breeding techniques improve the social capital of farmers: taking the integrated rice-crayfish farming technique as an example
TIAN Zhuoya, QI Zhenhong, YANG Caiyan, YANG Xingjie, WANG Xicong
 doi: 10.12357/cjea.20230436
Abstract(69) HTML(38) PDF(6)
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The economic and ecological functions of ecological farming and breeding techniques have received considerable attention, however, their social functions have been ignored. To explore the social function of ecological farming and breeding technique, this study analyzed the impact of the adoption behavior of integrated rice-crayfish farming techniques on social capital using a treatment effect model based on survey data of 1039 rice-crayfish farmers in the Jianghan Plain, Hubei Province. The results were as follows: 1) The social function of the integrated rice-crayfish farming technique was extremely prominent. In other words, the adoption of the integrated rice-crayfish farming technique significantly boosted the farmers’ social capital. After farmers adopted this technique, the total level of social capital increased by 0.047 units, of which the scale of social networks expanded by 114.266 units, while the status of social networks decreased by 3.595 units. 2) From the mechanism perspective, the adoption of integrated rice-crayfish farming technique boosted farmers’ social capital by promoting their cooperative participation and Internet use. 3) From the heterogeneity analysis, there was income and age heterogeneity in the impact of integrated rice-crayfish farming technique adoption behavior on social capital; the adoption behavior of integrated rice-crayfish farming techniques had a more pronounced effect on the social capital of high-income farmers and farmers under 60 years old. Therefore, it is necessary to understand and evaluate the social functions of integrated rice-crayfish farming technique in order to promote social capital accumulation among farmers.
Response of farmland soil aggregate-associated organic carbon to straw return: a meta-analysis
LI Yiran, WANG Xiuxin, LIANG Yaowen, ZHOU Haifeng, ZHOU Nanding, PU Yulin
 doi: 10.12357/cjea.20230158
Abstract(91) HTML(57) PDF(27)
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Straw return is a practical method for effectively improving soil organic matter (SOM) and is favored owing to its simplicity and cost-effectiveness. In this study, we screened 35 relevant experimental field studies to investigate the effects of straw return on farmland soil aggregate organic carbon content. We used meta-analysis and random-forest models to evaluate the response effects of farmland soil aggregate carbon content to straw return, as well as the contribution of influential factors of farmland soil aggregate carbon content, such as geographical region, return mode, return amount, and years of straw return. This could provide a theoretical basis for enhancing soil quality and carbon sequestration, as well as for developing a reasonable aggregate carbon pool management strategy. Compared to that of the control treatment (no straw return), the carbon content of soil aggregates in China increased considerably when straw was returned to the farmlands. The positive effects of straw return on farmland soil aggregate carbon content varied remarkably across different regions in China. The highest positive effect of straw return on farmland soil aggregate carbon content was observed in Southwest China, ranging from 26.5% to 43.4%, whereas north China had the lowest positive effect of straw return on farmland soil aggregate carbon content, ranging from 2.0% to 10.8%. The beneficial impacts of straw return on farmland soil aggregate carbon content were moderate in Northeast, Northwest, East, and Central China. In addition, among the four straw return methods, including high stubble retention, mulching, rotary tillage and deep ploughing, rotary tillage had the largest influence on the rise of farmland soil large aggregate carbon content and small aggregate carbon content, ranging from 13.5% to 18.7%. High stubble retention had the highest improvement effect on farmland soil microaggregate carbon content, with a value of 19.5%. With respect to the years of straw return, the positive effects of straw return on farmland soil aggregate carbon content improved along with increasing amounts and the years of straw return. Furthermore, the beneficial effect of straw return on farmland soil aggregate carbon was most significant eight years after straw return. Additionally, the results of random-forest model showed that geographical region and straw return mode are important factors affecting farmland soil aggregate carbon with various particle sizes under the conditions of straw return, and their contribution rate was in the range of 16.2%–28.1% and 8.0%–22.4%, respectively. We also discovered that the crucial physical process by which straw return improves the organic carbon content of farmland soil on a broad scale is an increase in the physical carbon sequestration of soil aggregates. As aforementioned, it is suggested that the straw should be returned to the farmland soil within a 15 cm depth using the rotary tillage method after crushing, and simultaneously an appropriate amount of chemical fertilizer (e.g., nitrogen and phosphorus fertilizer) should be applied to maximize the potential of soil aggregates for carbon sequestration.
Effects of organic and conventional management on soil carbon sequestration in tea gardens: comparison with forest land
ZHENG Yuting, HUANG Xinhui, LI Hao, WANG Biao, LI Panfeng, CUI Jixiao, SUI Peng, GAO Wangsheng, CHEN Yuanquan
 doi: 10.12357/cjea.20230429
Abstract(117) HTML(67) PDF(20)
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To explore the effects of organic and conventional management methods on soil organic carbon in tea gardens, we selected three typical land use types in Simao District, Pu’er City, Yunnan Province to carry out the investigation. The three land use types were a conventionally managed tea garden, an organically managed tea garden, and a nearby natural forest land. Based on the land use types, we measured the contents of soil organic carbon (SOC), easily oxidizable organic carbon (EOC), non-liable organic carbon (NLOC), particulate organic carbon (POC), and mineral-associated organic carbon (MOC) in 0−20 cm and 20−40 cm soil layers in three sample plots. We estimated the distribution ratio of the different types of organic carbon in soil and the soil carbon pool management index (CPMI), and analyzed the changes of the content of SOC component and quality of soil carbon pool from the selected land use types. The results were as follows: 1) the content and storage of SOC in the 0–40 cm soil layer of the conventionally managed tea garden were significantly lower than those in the natural forest land by 48.67%−51.94% and 27.25%−35.71% (P<0.05), respectively. The content and storage of SOC in the 0−40 cm soil layer of the organically managed tea garden were respectively 52.09%−62.86% and 15.54%−20.26% higher than those in the conventionally managed tea garden (P<0.05). 2) In the 0–20 cm and 20–40 cm soil layers, the contents of EOC, NLOC, POC, and MOC in the soils from the tea garden under conventional management were significantly lower than those from the natural forest land (P<0.05). The contents of EOC, NLOC, POC, and MOC in the soils from the organically managed tea garden were significantly higher than those from the conventionally managed tea garden (P<0.05), which were higher by 46.39%–57.89%, 54.24%–66.15%, 80.87%–121.01%, and 40.07%–46.28%, respectively. 3) The POC/SOC and NLOC/SOC of the tea garden under conventional management were lower than those of natural forest land, while the POC/SOC and NLOC/SOC of organically managed tea garden were higher than those of conventionally managed tea garden. 4) Conventionally managed tea gardens had high CPAI and low CPMI. The CPMI of conventionally managed tea garden was 24.53%−46.12% lower than that of the natural forest land (P<0.05), and the CPMI of organically managed tea garden was 67.88%−100.33% higher than that of conventionally managed tea garden (P<0.05). The aforementioned results showed that when compared with natural forest land, the reclamation of tea plantations with conventional management measures can reduce SOC content and soil carbon pool quality, resulting in a certain degree of land degradation. Given the limitations of conventional management, organic management is an effective measure for improving the quality of the soil carbon pool in tea plantations.
Effects of high temperature stress during pollination on plant morphology, leaf photosynthetic characteristics, and yield of summer maize
MU Xinyuan, MA Zhiyan, LU Liangtao, LYU Shanshan, LIU Tianxue, HU Xiuli, LI Shuyan, JIANG Hantao, FAN Yanping, ZHAO Xia, TANG Baojun, XIA Laikun
 doi: 10.12357/cjea.20230282
Abstract(116) HTML(41) PDF(12)
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High temperatures during the flowering period seriously affect the safe production of summer maize in the Huang-Huai-Hai region. In this experiment, the heat-sensitive variety ‘Xianyu 335’ was used as the test material; the effects of high temperature stress during pollination on plant morphology, leaf photosynthetic characteristics, dry matter accumulation and distribution, and yield of summer maize were studied by setting up normal field temperature treatment (CK) and high temperature treatment during pollination (HT). The results showed that in 2021 and 2022, the number of days with maximum canopy temperatures exceeding 40 ℃ in the HT treatment group was 7 and 8 d, respectively, and the maximum canopy temperatures in the HT treatment group were higher than those in the CK group by 1.7−6.8 ℃ and 1.5−4.6 ℃, respectively. HT treatment significantly increased the plant height and ear height of summer maize but had no significant effect on stem diameter and green leaf area during the high-temperature treatment period. However, HT treatment delayed leaf senescence in the late reproductive stage of maize, and the green leaf area at maturity was 34.69% and 163.72% higher than that in the CK group in 2021 and 2022, respectively. During the high-temperature treatment period, leaf stomatal conductance, transpiration rate, and intercellular CO2 concentration were significantly higher and leaf carboxylation efficiency, stomatal limitation value, and water use efficiency were significantly lower in the HT treatment group than in the CK treatment group. The net photosynthetic rate of maize leaf in the HT treatment group varied with the treatment temperature: it significantly reduced when compared with that in the CK treatment group only when HT treatment temperature was too high (generally >40 ℃). High-temperature stress during pollination led to a decrease in the overall photosynthetic performance of the maize leaves. After exposure to 10 d of high temperature stress during pollination, the dry weights of maize stems, leaves, bracts, cobs, and individual plants decreased significantly. The dry weight of the cobs decreased the most, while those of the male ears and filaments increased significantly. HT treatment resulted in an increase in the partitioning of dry matter to stems, leaves, male ears, and filaments, and a significant decrease in partitioning to the cobs. At maturity, HT treatment significantly reduced the dry weights of maize grains and plant by 48.32% and 16.71%, respectively, while those of maize stems and leaves increased by 35.01% and 9.48%. HT treatment resulted in a significant decrease of 54.43% and 53.19% in the seed setting rate and grain number per ear, respectively; a significant increase of 10.13% in 100-grain weight; and a significant decrease of 46.82% in the grain yield. In conclusion, high temperature stress during pollination enhanced the stomatal transpiration of maize leaves, increased intercellular CO2 concentration, and decreased leaf carboxylation efficiency and water use efficiency. It also led to a decline in the overall photosynthetic performance of the plant and restricted the accumulation of photosynthetic products and their transfer and partitioning to the ear, resulting in a significant decrease in seed setting rate and grain number per ear. This decline also restricted the post-flowering transport of photosynthesized assimilated compounds from the “source” (stems and leaves) to the “sink” (grains), which ultimately led to a significant decrease in grain yield.
Spatial and temporal characteristics of ecological total factor productivity of grain in the Yangtze River Economic Belt
TIAN Hongyu, LIU Xing, SU Zhihao
 doi: 10.12357/cjea.20230418
Abstract(76) HTML(34) PDF(10)
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Environmental problems caused by increasing agricultural non-point source pollution and agricultural carbon emissions are one of the main challenges to sustainable agricultural development. Given the importance of grain production in agriculture, promoting low-carbon and green grain production is critical for coping with agricultural environmental threats. The Yangtze River Economic Belt is the core area of grain production in China; therefore, accurately measuring the ecological total factor productivity of grain in the Yangtze River Economic Belt and systematically analyzing its temporal and spatial evolution characteristics can provide a data basis for promoting the sustainable development of agriculture in this region and realizing the goal of protecting the Yangtze River. Based on the grain production data of 110 prefecture-level cities in the Yangtze River Economic Belt from 2011 to 2020, this study first measured the agricultural carbon emissions, agricultural non-point source pollution, and ecological value of grain cultivation, then constructed a calculation model that included both desired and non-desired outputs to measure the ecological total factor productivity of grain and finally applied the super-efficient Slacks-Based Measure (SBM) model and the global Malmquist Luenberger total factor production index to calculate and analyze the ecological total factor productivity of grains in the Yangtze River Economic Belt. The results show that: 1) the ecological total factor productivity of grain in the Yangtze River Economic Belt showed an overall growth trend from 2012 to 2020, with an average annual growth rate of 0.98%. The decomposition index of the ecological total factor productivity of grain showed that the technical efficiency was 0.9998, less than 1, whereas the technical progress index was 1.0273, greater than 1. The decomposition index indicated that the growth of the ecological total factor productivity of grain in the Yangtze River Economic Belt relied mainly on technical progress rather than technical efficiency. 2) From the perspective of spatiotemporal characterization, the ecological total factor productivity of grain in all prefecture-level cities in the Yangtze River Economic Belt achieved a more obvious improvement from 2012 to 2020, indicating that the green and sustainable development of grain in this region had achieved relatively good results. In terms of the decomposition indicators of the ecological total factor productivity of grain, the technical efficiency of all prefecture-level cities did not show a clear pattern, whereas the technical progress indexes of each prefecture-level city showed a continuous improvement trend. 3) In terms of regional comparison, the ecological total factor productivity of grains in the upstream area of the Yangtze River was the highest during the study period, reaching 1.0189, followed by the midstream region (1.0111); the lowest was in the downstream region (1.0014). Nevertheless, the ecological total factor productivity of grains increased in all three regions over time. Therefore, in the process of promoting sustainable grain production in the Yangtze River Economic Belt, it is essential to attach great importance to the role of technical progress and compensate for the shortcomings of technical efficiency as soon as possible.
Proceedings in carbon footprint research of food systems
XUE Jiamin, XU Minggang, ZHANG Jianjie
 doi: 10.12357/cjea.20230445
Abstract(31) HTML(8) PDF(11)
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Carbon footprint of food systems is one of the important research fields in response to climate change, and it is also a key method to measure carbon emission in agricultural production. The study of carbon footprint of food systems is helpful to accurately understand the characteristics and rules of carbon emissions in agricultural production, and provides scientific basis for formulating strategies and realization paths towards reduction of agricultural carbon emission, which is of great significance for the achievement of green development of agriculture. In recent years, the domestic and overseas studies on the carbon footprint of farming, animal husbandry and food consumption link have continued to deepen, providing important scientific support for reduction of greenhouse gas emission and construction of more sustainable food systems. However, the research in this field is continuously progressing, and there are still many scientific problems to be solved in the future. This paper reviews the concept, research significance, main methods, current research progress at home and abroad, as well as future research difficulties and hotspots of carbon footprint. In terms of research boundary, the future carbon footprint research should be conducted from the perspective of sustainable food system and to quantify agricultural carbon footprint in the view of the whole "crop-animal husbandry-food processing-food consumption" chain, taking into account the carbon emission of rural residents' daily life. In the research object, pay attention to coordinate the relationship of multi-interest subjects, promote the overall synergy; In terms of research methods, it is suggested to consider the carbon sink function of soil and farmland ecosystem, and establish a monitoring system of carbon footprint with complete indexes and parameters. Regarding the reduction of carbon emission, attention should be paid not only to technological innovations, but also to lifestyle change and policy regulation. This study helps better understand the influence of food system on environment and climate, and provides scientific basis for the promotion of agricultural green development and policymaking on rural revitalization.
Spatiotemporal evolution and driving factors of soybean production in Sichuan Province
CHANG Jie, LIN Zhengyu, GAO Wenbo, DU Xingduan
 doi: 10.12357/cjea.20230386
Abstract(71) HTML(40) PDF(3)
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Sichuan Province is one of the 13 major grain-producing areas in China, as well as an important component of China’s emerging soybean planting area and southwest-producing area. Studies of soybean production patterns are crucial to Sichuan Province’simplementation of food security strategy and soybean industry development in Southwest China. This study analyzes the temporal and spatial evolution characteristics and driving factors of soybean production in China from 2000 to 2020 in Sichuan Province using the Gini coefficient, industrial concentration index, exploring spatial data analysis, and optimal parameters-based geographical detector. The findings were as follows: 1) from 2000 to 2020, soybean production in Sichuan Province fluctuated and increased, the spatial distribution was very uneven, and the agglomeration level increased and gradually concentrated in the hilly areas of central Sichuan. 2) There was a strong positive spatial correlation in soybean production, and the overall manifestations were high-high aggregation and low-low aggregation types. 3) The influences of resource elements, comparative income, geographical climate, and economic and social factors on soybean production pattern change were highly significant, and most of them showed the interaction effect of nonlinear enhancement and double factor interaction enhancement. Among them, the impact of resource input, comparative benefits, and altitude on soybean production pattern was relative high and fluctuating upward trend for a long time. The influence of temperature and rural household size increases rapidly, the influence of transportation conditions and regional GDP decreases, and the driving force of cropping pattern system is the weakest. Based on these results, soybean production in Sichuan Province should focus on breaking the resource and environmental constraints such as cultivated land fragmentation and rural labor shortage, vigorously developing the productive service industry, and comprehensively improving the mechanization level of soybean production. At the same time, it is necessary to strengthen the ability of scientific and technological innovation to improve the yield level of soybeans in Sichuan Province. Additionally, it is critical to further optimize the policy system of soybean production, agricultural machinery, socialized services, insurance, and other links. Finally, we should focus on natural risks, such as drought caused by climate change, and establish and improve the early warning and prevention mechanism of natural disaster risks of soybeans, to further strengthen the comprehensive risk resilience of the soybean industry in Sichuan Province.
Characteristics of agricultural carbon emissions and carbon peak analysis in Hunan Province
DENG Weizhong, XU Zhongjian
 doi: 10.12357/cjea.20230423
Abstract(77) HTML(24) PDF(5)
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Understanding the characteristics of and factors influencing agricultural carbon emissions in Hunan Province can provide a scientific basis for the development of green and low-carbon agriculture in Hunan Province. By reviewing the Hunan Statistical Yearbook and the statistical yearbooks of various cities and regions, we integrated the data on crop area, agricultural inputs, and livestock and poultry production, and calculated the agricultural carbon emissions of Hunan Province from 2007 to 2020 using the classical carbon emission calculation theory of the Intergovernmental Panel on Climate Change (IPCC). Taking 2007 as the base year, the Kaya carbon emission formula and Logarithmic Mean Divisia Index (LMDI) were used to analyze the influencing factors, whereas the grey prediction model GM (1, 1) was introduced to predict the carbon emissions of Hunan Province during the period of 2021–2040. The calculation results showed that the carbon emissions in Hunan Province were 6.15 × 107 t in 2020, and the carbon emission intensity was 1.01 t·(×104¥)−1, with the peak reached in 2015. Agricultural carbon emissions in Hunan Province showed a three-stage change. Due to the severe impact of the 2008 snow and ice disaster on agriculture, agricultural carbon emissions showed a decreasing trend during 2007–2008, a steady increase during 2009–2015, a peak in 2015, and an overall decreasing trend during 2015–2020. At the same time, there were obvious differences among different cities: Changsha, Xiangtan, Hengyang, Shaoyang, Yueyang, Changde, and Yiyang reached their peak carbon emissions around 2015, whereas the other cities failed to reach their peaks before 2030. Agricultural carbon emission intensity in all cities and towns in Hunan Province showed decreasing trend; the larger the agricultural carbon emission intensity in the base year, the larger the decrease in agricultural carbon emission intensity in the following years. The average coefficient of variation of agricultural carbon emissions in each city between 2007 and 2020 was 42%, whereas the average coefficient of variation of agricultural carbon intensity was 20%. This indicates that the difference in agricultural carbon emissions between cities was much larger than the difference in agricultural carbon intensity. The proportion of agricultural carbon emission sources followed the order of farmland utilization>livestock and poultry production>agricultural inputs. The level of regional economic development, labor force level, and total rural electricity consumption play major roles in increasing agricultural carbon emissions; the level of regional economic development and total rural electricity consumption are the main influencing factors, whereas agricultural production efficiency, agricultural industrial structure, regional industrial structure, and the reciprocal of the per capita electricity consumption of rural residents important roles in the process of decreasing agricultural carbon emissions. The study shows that agricultural carbon emissions in Hunan Province peaked in 2015.In order to achieve the goal of carbon neutrality and provide reference for the decision-making of agricultural carbon emission reduction in Hunan Province, this paper puts forward suggestions such as optimizing the industrial structure, promoting green innovation according to local conditions, and strengthening government functions.
Effect of agricultural factor marketization on agricultural non-point source pollution: the regulatory role of environmental regulation
LIU Mingyu, XIAO Haifeng
 doi: 10.12357/cjea.20230240
Abstract(56) HTML(26) PDF(1)
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This study aims to explore possible ways to mitigate agricultural non-point source pollution from the perspective of source management and market-oriented reforms in agriculture. Based on China’s provincial-level (excluding Hong Kong, Macao, Taiwan, and Tibet) panel data from 2004 to 2020, a dynamic panel model was constructed, and based on the theory of externality, the differential generalized matrix estimation method was applied to explore the impact effect and transmission mechanism of agricultural factor marketization on non-point source pollution, to further analyze whether there is a moderating role of environmental regulation in the transmission mechanism. Analysis of the impact effects showed the following: 1) The marketization of agricultural factors presented an inverted “U”-shaped dynamic evolution characteristic of non-point source pollution, which initially increased and subsequently decreased. 2) The analysis of the mechanism showed that the marketization of agricultural factors indirectly affected the non-point source pollution through its effects on planting structure, chemical inputs, and the scale of operation. In particular, the effect of marketization of agricultural factors on “non-food rate” and fertilizer input intensity was in an inverted “U” shape, and the effect of the per capita scale of operation exhibited no significant effect on the early stage of marketization but demonstrated a significantly positive effect on the later stage of marketization. 3) The environmental regulation had a significant negative moderating effect on the transmission mechanism of “non-food rate” and fertilizer input intensity and did not exhibit a moderating effect on the transmission relationship between scale of operation and non-point source pollution. Therefore, this study recommends further leveraging the impact of market-oriented reform within the long-term mechanism of agricultural non-point source pollution management. This process is based on the path-dependence of the “scale effect” “structural effect”, and “input effect” of agricultural non-point source pollution management, as well as the role of market-oriented reform within the long-term mechanism of managing agricultural non-point source pollution, based on the path-dependence of the “scale effect” “structural effect” and “input effect”. Based on these parameters, this study appears to further play the role of market-oriented reform on the long-term mechanism of agricultural non-point source pollution management and build a dual-track operation mechanism of “government-market” to improve agro-ecological environment and ensure sustainable agricultural development.
Can conservation tillage machinery drive the spatial spillover of the net carbon sink of conservation tillage?-Based on the perspective of cross-zone service of agricultural machinery
LI Yuanyuan, XUE Caixia, CHAI Chaoqing, LI Wei, YAO Shunbo
 doi: 10.12357/cjea.20230375
Abstract(77) HTML(44) PDF(3)
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Conservation tillage is an environment-friendly agricultural cultivation technique that distinguishes itself from traditional tillage, and its implementation relies on agricultural machinery. China’s unique situation as a large country with many small-scale farms has led to the development of a distinctive path for agricultural machinery in the form of cross-regional agricultural machinery services. Therefore, it is worth exploring whether conservation tillage machinery drives the spatial spillover of the net carbon sink of conservation tillage in the context of cross-regional agricultural machinery services. This study used panel data from 30 provinces in China (excluding Hong Kong, Macao, Taiwan, and Tibet) from 2000 to 2020. First, an exploratory spatial data analysis was used to reveal the spatial agglomeration characteristics of conservation tillage machinery and its net carbon sink. Second, the spatial spillover effect of conservation tillage machinery on net carbon sink was quantitatively analyzed using the spatial Durbin model. Furthermore, this study analyzed the heterogeneity of the spatial spillover effect of conservation tillage machinery on its net carbon sink from the dimensions of time, topography, and major grain-producing areas. The study found that: 1) from 2000 to 2020, mechanical power and the net carbon sink of conservation tillage increased from 22.55 million kW and 7.93 million t C in 2000 to 238.63 million kW and 33.17 million t C in 2020, with average annual growth rates of 12.52% and 7.42%, respectively. The growth trends were significant, and their development was closely synchronized. The spatial correlation results indicated that both of them mainly exhibited regional agglomeration characteristics with ‘high-high’ and ‘low-low’, showing a significant positive spatial correlation. 2) In the context of cross-regional agricultural machinery services, conservation tillage mechanical power significantly drove the spatial spillover effect of net carbon sink of conservation tillage. This manifested as a positive spatial spillover effect of the mechanical power of conservation tillage on the corresponding net carbon sink in neighboring provinces. Specifically, straw-returning mechanical power exhibited a positive spatial spillover effect, whereas no-tillage mechanical power, owing to its long-term implementation, mainly showed a negative spatial spillover effect, which can lead to crop yield reduction. 3) The spatial spillover effect of conservation tillage mechanical power on the corresponding net carbon sink exhibited heterogeneity across different time periods, topographies, and major grain-producing areas. In the temporal dimension, the spatial spillover effect was significantly positive and increased during the 2004–2009 and 2010–2013 periods. In the topographic dimension, the spatial spillover effect was positive in plain areas but negative in hilly and mountainous regions. Among the major grain-producing areas, the spatial spillover effect of conservation tillage mechanical power on the corresponding net carbon sink was more pronounced in rice-producing areas. The spatial spillover effect of no-tillage mechanical power was relatively prominent in the wheat-producing areas. The spatial spillover effect of the straw-returning mechanical power was essentially the same across the three major grain-producing areas. This study proposes measures to promote conservation tillage, establish an agricultural machinery service information platform, and enhance the level of conservation tillage of agricultural machinery and equipment. Additionally, the research findings hold significant reference value for how the government can use conservation tillage to contribute to the dual-carbon target.
Review of soil carbon cycling processes involving microplastics
ZHU Zhihong, ZHANG Jin, GAO Xiaodan, TAO Zhao, MA Nan, XU Yingde
 doi: 10.12357/cjea.20230460
Abstract(192) HTML(156) PDF(65)
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Soil organic carbon (SOC) sequestration is a key process driving soil fertility evolution and carbon (C) balance in terrestrial ecosystem. The impacts of microplastics on soil properties and processes have received increasing attention due to their persistence and ecological risks in soil ecosystem. However, the role and effect of microplastics on SOC cycling are still unclear. Microplastics can affect the sequestration and mineralization of SOC by indirectly influencing soil physical and chemical properties, and directly participating in the soil C cycle, which further exacerbates the uncertainty of the SOC cycle process. Based on this background, this study outlined the development of SOC sequestration pathways, summarized the sources of microplastics in soils, explained the effects of microplastics on different soil C pools, and deeply discussed the possible mechanisms of microplastics regulating the soil C cycle. Finally, we summarized and prospected the research on SOC cycle involving microplastics. The results showed that microplastics could impact SOC balance by affecting the formation and destruction of soil physical structure, microbial community structure diversity, enzyme activity and functional genes, biofilm formation, animal reproduction and growth, plant growth and root deposition. Meanwhile, microplastics could directly affect SOC cycle by participating in the entire soil biogeochemical cycle. However, related research is still in its infancy, and how to choose scientific methods to distinguish and couple microplastic turnover and SOC cycle is difficult. In future research, it is necessary to further distinguish the contribution potential of microplastic-derived C in different SOC pools, to explore the coupling mechanism of microplastics directly and indirectly affecting the SOC cycle, and to carry out research on the participation of microplastics in the process of SOC cycle under the influence of multi factors through the embedding and improvement of advanced soil study methods, as well as the innovation and crossover of research ideas.
Abstract(85) HTML(107) PDF(2)
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Biodiversity Maintenance in the Rural Landscapes
Biodiversity maintenance and warning technology in rural ecological landscapes
XIE Zongqiang, ZHANG Yujun, WANG Yiqiang, GE Jielin, XU Wenting, XIONG Gaoming, XU Kai, MAO Jiangtao, CHEN Siqi, FENG Zhi
2023, 31(12): 1873-1882.   doi: 10.12357/cjea.20230408
Abstract(242) HTML(92) PDF(70)
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Biodiversity in rural landscapes plays a critical role in the vitalization and sustainable development of rural regions. We explored a set of methods for identifying biodiversity at different scales and uncovered the mechanisms that drive biodiversity in rural landscapes. We also formulated technical specifications for the maintenance of biodiversity from genes to ecosystems in rural landscapes. In addition, we developed a framework for biodiversity monitoring and warning systems in rural landscapes based on the Driving Force-Pressure-State-Impact-Response (DPSIR) conceptual mode. We developed a multiscale full-chain technology for biodiversity identification, maintenance, and warning in rural ecological landscapes. This study yielded powerful insights into the biodiversity maintenance mechanism in rural landscapes by integrating multidisciplinary research methods, such as literature research, field survey, and laboratory analysis, and filled the gap in biodiversity maintenance technology in rural ecological landscape construction. Our study plays a theoretical and practical foundation for the development of rural ecological construction models, planting design and configuration, and species selection for the construction of beautiful villages in China. Furthermore, this multiscale and full-chain technology developed for biodiversity identification, maintenance, and warning in rural ecological landscapes provides key technical support for the dynamic management of rural ecological resources and plays a fundamental role in rural revitalization and the construction of a beautiful China.
A classification and nomenclature scheme for rural vegetation based on the ecological-production-living functions
XIONG Gaoming, GE Jielin, MAO Jiangtao, XU Wenting, XU Kai, XIE Zongqiang
2023, 31(12): 1883-1895.   doi: 10.12357/cjea.20230359
Abstract(109) HTML(63) PDF(30)
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Agricultural intensification has simplified agricultural landscapes through the expansion of agricultural land, enlargement of field size, and removal of non-crop habitats. Rural vegetation is a key component of agricultural landscapes as it produces food, fiber and fuel, and performs ecosystem services, such as recycling of nutrients, regulation of microclimate, and local hydrological processes. Vegetation classification is the basis for surveying, monitoring, and managing rural vegetation. However, to date, green space vegetation, a cultivated vegetation type, has not been listed in the vegetation classification system of China, and little is known about its functional role in the production and regulation of rural landscapes. Here, we reviewed the literatures on different vegetation classifications in China and developed a renewal framework for rural vegetation classification systems. The system includes nine classification units. First, rural vegetation is classified into three vegetation categories: natural and semi-natural vegetation, agricultural vegetation, and green space vegetation (level 0, the highest-level unit). Then, each of the highest-level units is classified into three upper level units (levels 1–3, including the vegetation formation group, vegetation formation, and vegetation subformation), three middle level units (levels 4–6, including the alliance group, alliance, and suballiance), and two lower level units (levels 7–8, including the association group and association). We clarified the division basis and nomenclature for each classification level unit with examples and proposed a reference scheme for the classification and nomenclature of rural vegetation. Following the common classification principle of “plant community ecology”, which is widely used in China, we revised the classification principles and nomenclature based on the functions of the three vegetation categories. Natural and semi-natural vegetation focus on comprehensive ecological conditions and community appearance; agricultural vegetation highlights the functional use, cultivation conditions, and farming system of crops; and green space vegetation focuses on landscape appearance and community assembly. Based on this scheme, rural vegetation in China is classified into three vegetation categories, 23 vegetation formation groups, 66 vegetation formations, and 142 vegetation subformations. Natural and semi-natural vegetation includes 6 vegetation formation groups (Forest, Shrubland, Herbaceous Vegetation, Desert, Alpine Tundra and Sparse Vegetation, and Swamp and Aquatic Vegetation), 30 vegetation formations, and 81 vegetation subformations. Agricultural vegetation includes 13 vegetation formation groups (Food Crop, Vegetable Crop, Fruit Crop, Flower Crop, Oilseed Crop, Fiber Crop, Sugar Crop, Medicine Crop, Beverage Crop, Forage Crop, Tobacco Crop, Spice Crop, and Other Crops), 23 vegetation formations, and 40 vegetation subformations. Green space vegetation includes 4 vegetation formation groups (Arbor Green Space, Shrub Green Space, Herb Green Space, and Wetland Green Space), 13 vegetation formations, and 21 vegetation subformations. This study clarified the definition boundaries of different classification units and illustrated the nomenclature of various types of vegetation in current vegetation classification research. Thus, this study modified some shortcomings in the classification and nomenclature of agricultural vegetation and renewed the vegetation classification system of China by including green space vegetation. The results of this study are beneficial for the protection, management, and spatial planning of rural landscapes.
Plant genetic diversity of ecotourism rural landscape
FENG Zhi, YAO Zhi, SUN Quan, LI Meng, WU Xiuzhong, CHEN Dahua, JIANG Long, FAN Kaifang, TANG Jianlu, LI Kai, MI Xiaoqin, YU Yong, WANG Yiqiang
2023, 31(12): 1896-1908.   doi: 10.12357/cjea.20230326
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The incorporation of rural landscape plants plays a pivotal role in the development and establishment of ecotourism. By studying the genetic diversity of plants in rural landscapes, the richness of genetic variation and the stability of the genetic structure within a population can be revealed. This serves as an important theoretical foundation for the construction of rural ecological landscapes and biodiversity maintenance and is of great significance for the construction of beautiful villages. In this study, eight native landscape species were selected from two ecotourism villages (Changkou Village, Sanming City, Fujian Province; and Paifang Community, Nanjing City, Jiangsu Province). Native rural landscape plant samples were collected from the whole village area. Phenotypic characteristics were measured, and ISSR-PCR experiments were performed. Through analysis of phenotypic features and detection of molecular markers, the Shannon index and Nei’s genetic diversity indexes were calculated to elucidate the levels of genetic diversity of native landscape plant species in different areas. Cluster analysis using phenotypic features identified five types of Liquidambar formosana, six types of Cyclobalanopsis chungii, four types of Quercus glauca, sixteen types of Zelkova serrata, seven types of Toona sinensis, ten types of Aster indicus, five types of Chrysanthemum indicum, and six types of Rubus hirsutus. The phenotypic coefficient variation and Shannon index of the eight native landscape plant species ranged from 0.23 to 0.58, and from 1.51 to 6.74, respectively. In the total area, artificial area and natural area, the Nei’s genetic diversity indexes of the eight native landscape plant species ranged from 0.240 to 0.536, 0.244 to 0.540, and 0.193 to 0.367, respectively. For the eight native landscape plant species, the percentage of polymorphic loci varied from 45.00% to 100.00%, the number of alleles varied from 1.45 to 2.00, and the number of effective alleles varied from 1.30 to 1.64. The results revealed that the phenotypic (Shannon index) and molecular (Nei’s genetic diversity index) genetic diversity levels of the eight native landscape plant species were higher than the average diversity level in numerous other landscape plant species. Additionally, the rural landscape plant species exhibited abundant genetic variation. The genetic diversity of certain rural landscape plant species exhibited a notable degree of variability; however, there were significant differences in the levels of genetic diversity observed between natural and artificial areas. In the context of rural landscape construction, it is important to prioritize the assessment of genetic diversity in rural landscape plant populations. Appropriate measures should be implemented to enhance the even distribution of genetic polymorphisms within the population and preserve the genetic diversity of native landscape plant species. This approach is essential to ensure the long-term stability of rural ecological landscapes.
Effects of rural landscape spatial morphology on plant diversity in the Yangtze River Delta region
CHEN Siqi, PAN Kaichen, XU Shuyao, ZHANG Yujun
2023, 31(12): 1909-1920.   doi: 10.12357/cjea.20230360
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Analyzing rural plant diversity in relation to landscape spatial morphology is necessary to improve rural living environments and maintaining stable rural ecosystems and biodiversity. Fourteen villages in Jiangning District, Nanjing City, Jiangsu Province were selected as experimental areas, and models such as stepwise regression and NMDS-Envfit were used to explore the impact of rural landscape spatial indicators on the α diversity and β diversity of rural plants in the Yangtze River Delta region. Landscape indicators included two-dimensional plane forms, three-dimensional surface features, and four-dimensional historical dynamics. The research conclusions can be summarized as follows: 1) Landscape spatial morphological indicators, such as the percentage of the landscape area covered with semi-natural patches, landscape cohesion index, surface roughness, and patch Euclidean nearest neighbor distance, had relatively significant impact on plant diversity. The patch Euclidean nearest-neighbor distance and patch area significantly and negatively affected the diversity of the arborous layer. Patch fragmentation, higher road density, and higher comprehensive dynamic degree of land use had a negative impact on the α diversity of shrub layer, while the distance from the road obviously affected the α diversity of herbaceous layer. 2) Rural landscape spatial morphological indicators had an impact on plant β diversity. Specifically, in the arborous layer, surface roughness and percentage of landscape area covered with semi-natural patches were the most important influencing factors. In the shrub layer, surface roughness and Shannon diversity index were the most important influencing factors. In the herbaceous layer, patch area and rural road density were the most important influencing factors. 3) Considering the significance of landscape indicators, landscape ecological indicators and three-dimensional surface characteristics had the most significant impact on plant diversity. The main manifestations were the positive correlation between the proportion of semi-natural patch area, patch area, cohesion degree, surface roughness, and plant diversity. The historical dynamics of the four-dimensional landscape had a weak impact on plant diversity, mainly manifesting as a positive correlation with the dynamic degree of semi-natural patches. Two-dimensional landscape indicators based on urban spatial morphology had the weakest impact on plant diversity, mainly manifesting as the negative effects of rural spatial accessibility and road density on plant diversity. Based on the above results, landscape response strategies are proposed to provide guidance for the rural landscape construction process, such as effectively increasing the proportion of semi-natural habitat areas and landscape heterogeneity, comprehensively improving rural landscape cohesion, scientifically maintaining rural high-value woodland landscapes, and fully focusing on rural historical land use. This study provides a reference for the maintenance of biodiversity during rural landscape construction and useful quantitative guidance for rural spatial planning in the Yangtze River Delta region.
Characteristics and maintenance strategies of plant diversity in an ecologically protected rural village in western Fujian
GE Jielin, XIONG Gaoming, XU Wenting, MAO Jiangtao, QIN Xiaoqiong, MA Boyu, XU Kai, GAO Luxin, LI Jiaxiang, WU Yuanshuai, XIE Zongqiang
2023, 31(12): 1921-1931.   doi: 10.12357/cjea.20230378
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Plant diversity plays a fundamental role in rural ecological revitalization and sustainable development. Studying the characteristics and influencing factors of rural plant diversity has important theoretical and practical implications for maintaining and enhancing rural biodiversity. In this study, we identified the composition and community types of plant species and explored the effects of natural and human activities in Changkou Village, an ecologically protected village in western Fujian Province. We identified 578 plant species belonging to 130 families and 378 genera, including 396 wild plant species and 53 cultivated agricultural species, exhibiting high plant diversity. Seventeen species of invasive plants have not yet posed a threat to rural biodiversity. The seed plant flora in this rural area was complex, with 14 types of genera, including 188 tropical genera, and showed transitional features from tropical to temperate zones. There were 106 plant vegetation alliances, including 52 natural and semi-natural vegetation, 25 agricultural vegetation, and 29 green space vegetation alliances, which were representative of this region. Natural and semi-natural vegetation were mainly composed of different natural and semi-natural forests, such as the Castanopsis fargesii Forest Alliance and Pinus massoniana + Castanopsis fargesii Forest Alliance, whereas agricultural and green space vegetation areas were very small. Green space vegetation was mainly composed of Cinnamomum camphora and Osmanthus fragrans, and green space tree species predominated in subtropical rural areas. Furthermore, there was a significant positive correlation between the differences in species composition in different rural areas and differences in comprehensive environmental factors. Specifically, the plant species composition of natural and semi-natural vegetation was mainly driven by natural factors, whereas the differences of plant species composition of green space vegetation significantly increased with the increasing distance to roads and residential areas. Overall, these results indicate that ecologically protected rural areas are important reserves for plant diversity and have important maintenance value. The composition of plant species and vegetation alliances completely differs between different vegetation categories in rural areas, and altitude plays a key role. We highlight the necessity of incorporating ecological conservation-oriented rural areas into biodiversity conservation management, and emphasize various maintenance and improvement strategies, such as zoning management of rural plant diversity and building habitat networks. This study could provide useful references for promoting plant diversity in the process of rural revitalization in other regions of China.
Invasion characteristics and influencing factors of Solidago canadensis in leisure-tourism villages in the south of the Yangtze River
GE Jielin, XIONG Gaoming, MAO Jiangtao, XU Wenting, QIN Xiaoqiong, XIE Zongqiang
2023, 31(12): 1932-1942.   doi: 10.12357/cjea.20230377
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Invasive plants pose a serious threat to plant diversity in rural areas, weaken their ecosystem service functions, and have become a prominent issue that urgently needs to be addressed in rural revitalization and beautiful rural construction. In this study, based on survey data from 127 sampling sites, we aimed to explore the degree of invasion and influencing factors of the invasive plant Solidago canadensis in a leisure-tourism village located in south of the Yangtze River. The height of S. canadensis showed a normal distribution, whereas its coverage showed a significantly positively skewed distribution. In rural areas, it displayed a multipoint scattered distribution pattern, forming a single optimal community locally and exhibiting a trend of further potential dispersal. We also found that the height and coverage of S. canadensis were significantly affected by various factors in rural environments. Specifically, the height of S. canadensis was negatively correlated with the species number and coverage of native plant species in the community, in which the number of native plant species played a more important role. In contrast, the coverage of S. canadensis showed a decreasing trend with increasing distance from the farmland, and the species number and coverage of native plant species. The interaction between the number of native plant species and coverage significantly suppressed the coverage of S. canadensis, and the inhibitory effect of native plant coverage on the coverage of S. canadensis increased with the increase in the number of native plant species in the rural community. In conclusion, leisure-tourism villages have been severely affected by the invasion and spread of S. canadensis. This study also identified the fundamental role of multiple community attributes of native plant species in resisting the invasiveness of single alien plant species and broadened our current understanding of the invasion mechanism of single invasive plants in rural landscapes. These findings emphasize the urgent need to incorporate the monitoring and prevention of invasive plant species into rural ecological landscape planning for the development of leisure tourism in the future, thus providing a solid scientific basis for the comprehensive prevention and control of invasive plants in different rural areas and the maintenance of rural biodiversity during the construction of beautiful rural areas.
Biodiversity early warning of rural ecological landscape based on DPSIR model
XU Wenting, XIE Zongqiang, GE Jielin, XU Kai, XIONG Gaoming, MAO Jiangtao
2023, 31(12): 1943-1952.   doi: 10.12357/cjea.20230622
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In view of the potential threats to biodiversity in the process of rural revitalization and the needs of conservation and management, this study organically combined the theories and methods of biodiversity with society, economy, population, etc., and built the early warning index system of biodiversity in rural ecological landscape based on the DPSIR (Driving Force-Pressure-State-Impact-Response) model. Based on the principles of scientificity, relevance, practicality and comparability, the index system reflects the impact of human interference, global change, major disasters, measures and inputs taken by human to maintain the biodiversity of rural ecological landscape, and other factors on rural biodiversity, including 12 factors and 25 indicators of the driving force, pressure, state, impact and response of biodiversity. The mean square deviation method was used to determine the weight value of each index, divide the evaluation level. And the comprehensive index method was used to warn the biodiversity of the rural ecological landscape. The rural biodiversity in this study comprehensively considered the “Ecology, Production, Living” functions of the countryside. Therefore, the species of wild animals and plants, crop species, and rural green plants were all included in the calculation of the biodiversity index. This research method has been applied in the Paifang Community of Nanjing to give early warning to the high risk area. This study provides a new idea and method for biodiversity protection and evaluation in the revitalization and planning of green livable countryside, and it is of great significance to build a beautiful countryside with green harmony.
Agroecosystem and Its Management
Effect of fertilizer types on antibiotic resistance genes and bacterial community in vegetable fields
ZHENG Ziying, DING Lin, YANG Jing, HAN Wanxue, LIU Jin, WANG Xinzhen, WANG Fenghua
2023, 31(12): 1953-1962.   doi: 10.12357/cjea.20230270
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Farmland ecosystems are essential sources and sinks of antibiotic resistance genes (ARGs), and the application of livestock manure is a major contributor to ARGs in soil. The massive application of livestock manure to vegetable fields has intensified the pollution caused by ARGs in soil. Raw consumption of edible vegetables is one of the most direct ways to introduce ARGs from the soil–plant system to humans, which poses a potential threat to human health. However, few studies have investigated the effects of different fertilizer types on ARGs and bacterial communities in vegetable fields. In this study, 21 soil samples (0–20 cm) were collected from vegetable fields in Hebei Province using different fertilizer types (fresh fowl manure, fresh sheep manure, fresh cattle manure, commercial organic fertilizer, and chemical fertilizer). The distributions and characteristics of ARGs and bacterial communities in vegetable fields were investigated using real-time quantitative polymerase chain reaction (PCR) and high-throughput sequencing techniques. Eight tetracycline resistance genes (tetA, tetC, tetG, tetL, tetO, tetM, tetW, and tetQ), two sulfonamide resistance genes (sul1 and sul2), and one intI1 gene were detected in all vegetable fields. The absolute abundance of sulfonamide resistance genes (9.96×109 copies·g−1 in dry soil) was significantly higher than that of tetracycline resistance genes (1.07×109 copies·g−1 in dry soil). The application of livestock manure and chemical fertilizer both significantly increased the abundance of ARGs in vegetable fields. The highest abundance of ARGs (6.34×109 copies∙g−1 in dry soil) was found in vegetable fields with higher chemical fertilizer amendment, while the lowest abundance of ARGs (3.09×108 copies∙g−1 in dry soil) was found in vegetable soil with commercial organic fertilizer. In addition, the Shannon and Chao1 indices, representing the α diversity of the soil bacterial community, were significantly higher in soil fertilized with livestock manure compared to high-chemical fertilizer application but not in low-chemical fertilization soil, indicating that livestock manure application significantly increased the abundance and diversity of the soil bacterial community. Pearson’s correlation analysis showed that soil bacterial community structure was an important factor influencing the distribution of ARGs. Proteobacteriota, Bacteroidota, Actinobacteriota, and Firmicutes were the dominant potential hosts of ARGs and were significantly correlated with sulfonamide and tetracycline resistance genes (P<0.05). The distribution of ARGs was also affected by soil organic matter and total nitrogen content. The intI1 gene had significant and positive correlations with the sul2, tetG, tetQ, and tetW genes, suggesting its crucial role in ARGs dissemination. In the present study, the use of higher concentrations of chemical fertilizers led to a significantly increased abundance of ARGs in the soil of vegetable fields, whereas the application of commercial organic fertilizers had the least effect on ARGs abundance. This study serves as a guide for evaluating the status of ARGs pollution in vegetable fields with different fertilizer types.
Impacts of field margins and organic practices on arthropod natural enemy and pest diversities in paddy fields
MENG Xuan, LI Jianing, FAN Shunxiang, LIU Xinyu, LIU Yunhui
2023, 31(12): 1963-1975.   doi: 10.12357/cjea.20230395
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Although the expansion of agricultural land and intensive production have contributed to increased food production, the resulting high-intensity human disturbances and excessive use of agrochemicals have caused significant environmental damage. This has led to the loss of biodiversity and degradation of ecosystem services, ultimately posing threats to both sustainable food production and human health. Therefore, it is crucial to develop sustainable production management strategies. Organic production at the field scale and the establishment of flowering boundaries are considered efficient measures for biodiversity and ecosystem services. However, few studies have investigated whether organic practices and flowering boundaries can effectively increase the natural enemies of arthropods and improve the control of pests in cultivated fields, particularly in paddy planting systems. In this study, we aimed to fill this knowledge gap by investigating the distribution and diversity of natural enemies and pests of arthropods in paddy fields and their field margins, and how vegetation on the field margin affect diversities of natural enemies and pests of arthropods in paddy fields. The following three treatments were established: conventional paddy fields with traditional field margins (Con), organic paddy fields with traditional field margins (Org), and organic paddy fields with flowering boundaries (OrgF). Arthropods were sampled at the field margins and in paddy fields 5 and 20 m away from the margin using a suction sampler. Vegetation coverage and diversity in the field margins were also investigated. The results are as follows: 1) a total of 9531 arthropods belonging to 50 families were caught, with 2653 individuals identified as natural enemies from 28 families (including 2253 individual spiders belonging to 14 families and 41 species), and a total of 3971 individual pests representing 18 families (dominated by Cicadellidae, accounting for 84.01% of the total pests). 2) The richness of the natural enemies in Org was greater than that in Con. The richness of natural enemies in OrgF was higher than that in Con and Org, and the abundance of natural enemies in OrgF was higher than that in Con. 3) In OrgF, the abundance and richness of natural enemies at different distances between the boundary of the paddy field and the interior of the paddy field were significantly different, with a greater richness of natural enemies in the paddy field 5 m away from the field margin than at 20 m. Furthermore, the abundance of natural enemies was significantly lower at the field margins than in paddy fields 5 m away from the boundary. 4) The richness and abundance of natural enemies and pests in paddy fields and their boundaries were positively correlated with vegetation coverage at the paddy field boundary. 5) The ratio of enemies to pests was the highest in the conventional paddy fields (Con), as most pests might be killed by broad-spectrum insecticides, followed by Org and OrgF, which had a large number of pests with only targeted bio-pesticides being used. In conclusion, organic practices in the fields and the flowering boundaries can effectively help to maintain arthropod diversity and increase the diversity of natural enemies in paddy fields. However, to effectively control pests and improve biological control services, an in-depth understanding of the plant-arthropod relationship and careful selection of the “correct” plant diversity are required.
Seasonal effects of snow cover on soil soluble carbon and nitrogen content and microbial activity
WANG Enliang, WEI Chang
2023, 31(12): 1976-1983.   doi: 10.12357/cjea.20230323
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Global warming is becoming increasingly serious, and the complicated climate change situation has led to obvious changes in global snow cover patterns. Therefore, we explored the effects of future climate warming on the physical and chemical properties of black soil in Northeast China. This study adopted the method of artificial snow depth control from November 2020 to May 2022 and divided the plots in the test area into three treatment groups: snow increase (TS), snow removal (TR), and control (C). Soil environmental factors, available carbon and nitrogen contents, microbial biomass, urease activity, and sucrase activity were determined. The seasonal dynamic change process of each index was analyzed. Long-term field experiments showed that snow removal significantly reduced soil temperature and humidity. In addition, lower soil temperature and humidity accelerated the release of soil nutrients, and significantly increased the contents of soil nitrate nitrogen and ammonium nitrogen in early winter, while the opposite was true with snow increase treatment. However, from the beginning of the deep snow period, the snow removal treatment caused a loss of soil inorganic nitrogen to a certain extent while increased contents of soluble organic carbon and nitrogen. The snow removal treatment maintained soil microbial activity at a high level for most of the winter. However, at the end of winter, owing to the rapid release of soluble organic matter under snow treatment, soil microorganisms under snow treatment absorbed a large amount of nutrients and exist in a more suitable soil environment, which significantly increases the soil microbial activity under the snow treatment. However, owing to the loss of heat insulation from snow cover, a large number of microorganisms decomposed and died at this time, which significantly reduced soil microbial activity. Before and after the test period, snow treatment significantly increased the soil microbial activity by 23.07 mg∙kg1, and snow removal treatment significantly increased the soil microbial activity by 11.92 mg∙kg1, with a difference of 93.5%. The decrease in snow cover significantly decreased the activities of soil urease and sucrase during most of the winter, and the activities of soil urease and sucrase were significantly increased by snow treatment. These results show that the activities of these two enzymes increased significantly by more than 10.5%. In summary, this study demonstrated that changes in snow cover in the future will lead to changes in the dynamic change characteristics of soil available carbon and nitrogen and microbial activity, and the influence of snow cover change on soil enzyme activity will also indirectly affect the soil nutrient cycling process and physical and chemical properties of soil. The results of this study provide a theoretical foundation and scientific basis for further research on the material cycle of terrestrial ecosystems in the black soil region of northeast China in the context of climate warming.
Crop Cultivation and Physiological Ecology
Energy use efficiency and greenhouse gas emissions of oil crops in China
CHEN Li, LIU Juan, WANG Mo, LI Mu
2023, 31(12): 1984-1996.   doi: 10.12357/cjea.20230283
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Energy is a major component in enhancing agricultural productivity. Accounting for energy efficiency at the production stage of crop is essential for achieving sustainable agriculture. Due to the high level of production and consumption of oil in China, it is of great importance to pay attention to energy consumption and its negatively environmental impacts in the oil production process. Measures of optimizing energy utilization structure, reducing excessive and ineffective energy consumption and improving energy utilization efficiency can be used, in order to increase income, save cost and reduce greenhouse gas emissions synthetically. Academically, a large number of previous studies have contributed to energy use and environmental impacts in the production of oil crops, fruits, vegetables, and food crops on various scales. However, there is a lack of studies related to energy use efficiency and greenhouse gas emissions in oil production which concentrate in major oil crops production areas nationally so far. Generally, in terms of models used in relevant study areas, methods including life cycle assessment (LCA), data envelopment analysis (DEA), process analysis, energy analysis have been used commonly, which provide valuable references to the present study. Given that oil crops production is inherently a life process, this paper combined LCA+DEA methods to estimate the energy utilization efficiency and greenhouse gas emissions of oil crops, which helped to rank efficient and inefficient provincial production units. In further, the underlying reasons which caused inefficient energy use were deeply identified in different provinces. Additionally, for purpose of practical application, this paper explored the possibility and potential of energy saving and GHG emission reduction in each province. The results showed as follows. 1) There was no significant difference in the output capacity per unit energy consumption among the three studied oil crop systems. However, the energy use efficiency of three oil crops displayed remarkably differently, which showed peanut > oilseed rape > soybean. 2) Among the three oil crops, peanut had the highest GHG emissions [874.96 kg(CO2 eq)∙hm−2], followed by oilseed rape [660.16 kg(CO2 eq)∙hm−2] and soybean [507.07 kg(CO2 eq)∙hm−2]. In addition, the contributions of substantiality inputs and agricultural operations to GHG emissions varied greatly from different oil crops. Specifically, the significant GHG emission source of oilseed rape and peanut was fertilizer. Nevertheless, contribution of fertilizer, diesel fuel and irrigation to the GHG emissions of soybean showed less difference. 3) There was great potential for energy utilization optimization and GHG emission reduction. Estimates resulted from this study displayed that about 11.97%, 16.38% and 15.89% of resources invested to oilseed rape, soybean and peanut in inefficient provinces could be saved respectively, which were capable of reducing 20.60−616.32 kg(CO2 eq)∙hm−2 GHG emissions as well. Therefore, it is necessary to optimize the energy utilization structure of low efficiency areas according to the actual situation, and explore the production mode of double optimal yield and carbon emissions. This will play an important role in saving money and increasing income for regional oilseed cultivation, as well as green development.
Meta analysis of the effects of foliar Se application on grain yield, protein content, and Se accumulation of winter wheat
NIE Haoliang, HUANG Shaohui, YANG Junfang, YANG Yunma, ZHANG Jing, YANG Huimin, YANG Wenfang, XING Suli, JIA Liangliang, YUE Zengliang
2023, 31(12): 1997-2010.   doi: 10.12357/cjea.20230229
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To quantitatively analyze the impact of foliar Se application on grain yield, quality, and Se accumulation in winter wheat in China, 41 published studies (36 in Chinese and 5 in English) with a total of 379 pairs of samples were collected. A Meta-analysis was used to comprehensively analyze the effects of foliar Se application on the yield, grain protein, and Se content of winter wheat, and a subgroup analysis was used to evaluate the effects of different factors on response of winter wheat to foliar Se application, with no Se application as the control group and foliar Se application as the experimental group. The results showed that compared with no Se application, the yield, grain protein, and Se contents of winter wheat were increased by foliar Se application, with incremental rates of 3.80%, 2.44%, and 764.56%, respectively. In terms of the different regions, the effect of foliar Se application on yield and quality improvement was greater in the east and south than in the west and north, respectively. Overall, the effect of grain Se enrichment gradually decreased from west to east. In terms of foliar Se application management factors, it was most worthwhile to apply 15−60 g·hm2 once at the early filling stage or twice at the boot stage and early filling stage, which would meet the standard of Se enrichment and human needs. Soil fertility was an important factor influencing the effect of foliar Se application on the yield and quality of winter wheat. Soil contents of Se and total N had a significant effect on yield-increasing effect of foliar Se application. The effect of foliar Se application on yield improvement was the highest when the Se content of soil was between 0.2–0.4 mg·kg1. The effect of foliar Se application on winter wheat yield decreased with increasing total soil N. Soil Se, total N, available P, and available K contents significantly affected the effects of foliar Se application on protein content. The effect of foliar Se application on grain protein was higher when the soil Se content was between 0.2−0.4 mg·kg1, total N>1.5 g·kg1, available P>20 mg·kg1, and available K=100−200 mg·kg1. Soil fertility (soil Se content, organic matter content, and available K content) was the main factor affecting Se accumulation in grain when Se fertilizer was applied to the foliar. When the soil organic matter and available K contents were enhanced, foliar Se application had significantly increased the Se accumulation; however, the effect of Se accumulation caused by foliar Se application was high in Se-poor soil (<0.2 mg·kg1). Therefore, foliar Se application measures and soil conditions for optimization in different regions not only synergistically achieve the goals of high yields, good quality, and Se accumulation standards of wheat, but also reduce environmental contamination, which provides support for sustainable wheat production management with Se enrichment.
Agricultural Resources and Environment
Rainfall partitioning patterns by Pinus tabulaeformis forest in Taihang Mountains
GUO Bo, YANG Hui, LI Jiacong, ZHU Chunyu, ZHAO Yuhan, CAO Jiansheng, SHEN Yanjun
2023, 31(12): 2011-2021.   doi: 10.12357/cjea.20230172
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The Taihang Mountain Region is the ecological barrier and water source of North China Plain. In recent decades, with the implementation of Taihang Mountains Greening Project and other projects, the vegetation coverage in Taihang Mountain Region is recovering continuously, but the runoff in the mountains is rapidly declining. The mechanism of how the vegetation restoration affects the water yield is not clear. The process of rainfall partitioning is an important part of hydrological cycle. It is of great significance for the formation process of regional water yield and water resources. Pinus tabulaeformis is the main afforestation tree species in Taihang Mountain Region, and it affects regional water resources. The rainfall partitioning of P. tabulaeformis forest in Taihang Mountain Region remains poorly understood. It is required to assess the applicability of the revised Gash model and revised Liu model. In this study, the rainfall partitioning in P. tabulaeformis forest is examined from July to November of 2022. The canopy interception was simulated by revised Gash model and revised Liu model. The results showed that 1) the rainfall amount was 450.8 mm during the study period, the average rainfall duration was 10.4 h, and the average rainfall intensity was 2.7 mm∙h−1. Furthermore, we found that the rainfall during the study period was mainly light rain. The canopy interception, throughfall and stemflow of P. tabulaeformis forest were 105.5, 338.2 and 7.1 mm, respectively, accounting for 23.4%, 75.0% and 1.6% of the rainfall amount. 2) Throughfall and stemflow began to occur when the rainfall amount reached 1.7 and 5.5 mm, respectively. Significant linear relationships were found between the rainfall amount and throughfall amount. However, the relationship between rainfall amount and interception followed a power function. The throughfall percentage increased quickly with increasing rainfall amount, but when rainfall amount reached 11 mm, the throughfall percentage increased slowly. The interception percentage firstly decreased and then stabilized with increasing rainfall amount. 3) Based on the revised Gash model, the canopy interception, throughfall, and stemflow were calculated to be 105.3, 340.7, and 4.6 mm, respectively. The relative errors between the measured and simulated values were 0.2%, 0.8%, and 34.7%. According to the revised Gash model simulation results, we found that the interception amount was dominated by canopy evaporation during rainfall, accounting for 55.0% of the interception simulation, followed by evaporation after cessation of rainfall, accounting for 27.8% of the interception simulation. The revised Liu model calculated the interception as 96.0 mm, with a relative error of 9.0% between the measured and simulated values. The revised Gash model had lower relative errors in the simulation than the Liu model. 4) Sensitivity of the revised Gash model parameters were mean evapotranspiration rate > mean rainfall intensity > canopy storage capacity > canopy cover > trunk storage capacity > stemflow coefficient. These results indicate that typical P. tabulaeformis forests in the Taihang Mountains can intercept 23.4% of rainfall, with 75.0% throughfall and 1.6% stemflow. The revised Gash model can be used to predict canopy interception in P. tabulaeformis forests and provides a theoretical basis for water resource assessment and water conservation capacity improvement in mountainous areas.
Agricultural Ecologic Economics and Ecoagriculture
Research on the effects of rural land consolidation on agricultural carbon emissions: a quasi-natural experiment based on the high-standard farmland construction policy
XIONG Feixue, ZHAO Xinglei, GUO Ziyi, ZHU Shubin
2023, 31(12): 2022-2032.   doi: 10.12357/cjea.20230353
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Abstract:
Under the carbon emission pattern of “carbon peak and carbon neutral”, agricultural carbon emissions, as one of the main sources of greenhouse gases, have become a key area for emission reduction. High-standard farmland construction is an important measure for promoting green, low-carbon, and high-quality agricultural development. An in-depth investigation of the effects and mechanisms of high-standard farmland construction policies on agricultural carbon emissions can provide an empirical basis for optimizing policy formulation and reducing agricultural carbon emissions. This is of great significance in promoting the development of low-carbon agriculture. Based on the theories of scale economy and division of labor, this study constructed a theoretical model of “high-standard farmland construction-agrochemical input intensity/socialized service-agricultural carbon emission”. Based on panel data from 30 provinces in China from 2007 to 2017, this study analyzed the effect and mechanism of the high-standard farmland construction policy on agricultural carbon emissions using a continuous differences-in-differences approach (DID) and mediation effect model. By measuring the agricultural carbon emissions of each province, this study found that national agricultural carbon emissions showed an inverted U-shaped trend, rising at the beginning, then declining, and peaking in 2015. Regions such as Henan, Shandong, Hebei, Jiangsu, and Anhui are at the forefront of agricultural carbon emissions nationwide, whereas regions such as Beijing, Shanghai, Tianjin, Hebei, and Shandong have higher rates of agricultural carbon emission reduction. The dynamic estimation results showed that the carbon reduction of the high-standard farmland construction policy had a lag effect, and the carbon reduction effect appeared in 2013 and continued to increase gradually. The results of the benchmark regression showed that a high-standard farmland construction policy significantly suppressed agricultural carbon emissions. On average, when all other conditions remained unchanged, implementing a high-standard farmland construction policy reduced agricultural carbon emissions significantly, i.e., by 10.1%. Robustness tests were conducted using the approach of substituting variables and considering the interference of other relevant policies. The results confirmed the positive effect of the high-standard farmland construction policy on reducing agricultural carbon emissions. The results of the mechanism analysis showed that agricultural chemical input intensity and agricultural socialized services played mediating roles in reducing agricultural carbon emissions through the construction of high-standard farmland. The construction of high-standard farmlands suppressed agricultural carbon emissions, mainly by reducing agricultural chemical input intensity and improving agricultural socialized services. Heterogeneity analysis revealed that the carbon reduction effect of the high-standard farmland construction policy mainly occurred in provinces with a high degree of land transfer and in non-food-producing areas. In contrast, it did not have a corresponding carbon reduction effect in provinces with a low degree of land transfer and in food-producing areas. Therefore, the government should strengthen the construction of high-standard farmlands and differentiate the implementation of high-standard farmland construction policies according to local conditions and classifications to give full play to the emission reduction effect. In addition, the government should pay great attention to the role of agricultural chemicalization and socialized agricultural services in carbon reduction effects.
Impact of informatization of agricultural extension services on farmers’ scientific fertilization technology adoption decisions
WANG Pan, LI Gucheng, LIU Di
2023, 31(12): 2033-2043.   doi: 10.12357/cjea.20230301
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Abstract:
Continuously promoting scientific fertilization is a powerful support for achieving a stable food supply and constructing an ecological civilization. To explore the effective strategies to promote scientific fertilization by Chinese farmers in the context of digital village construction, this study uses the Heckman two-stage model based on the data from 1256 surveys of farmers in the rice producing areas of Hubei Province to explore the influence of informatization of agricultural extension services on the adoption decision of scientific fertilization technology by farmers in terms of “adoption behavior” and “the degree of adoption”. Additionally, we analyzed the mechanism of informatization of agricultural extension services on scientific fertilization technology adoption decision by farmers using the stepwise regression method. The results are presented as follows: 1) The informatization of agricultural extension services had a significant positive effect on adoption behavior of farmers and the degree of adoption of scientific fertilization technologies. 2) There are differences in the effects of informatization of agricultural extension services on different types of scientific fertilization technologies. The informatization of agricultural extension services had a more significant effect on the adoption of efficient fertilization technologies by farmers than the application of new fertilizers. 3) The informatization of agricultural extension services promoted adoption behavior of farmers by improving benefit perception; it also promoted the adoption behavior of farmers and the degree of their adoption by reducing risk perception. Consequently, this study proposes policy recommendations to continuously enrich the forms and service contents of information-based agricultural extension services, improve the cooperative extension mechanism, and enhance the effectiveness of agricultural extension services through personalization and precision.

Editor-in-chief:LIU Changming

Competent Authorities:Chinese Academy of Sciences

Sponsored by:Institute of Genetics and Developmental Biology, Chinese Academy of Sciences; China Ecological Economics Society

Organizer:Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences

ISSN 2096-6237
CN 13-1432/S
  • Chinese core periodicals
  • Core Chinese Sci-Tech Periodicals
  • China's Top Science and Technology Periodicals
  • Covered by Chinese Science Citation Database (CSCD)
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