中国生态农业学报(中英文)

Effects of organic management on the diversity of α, β and γ of herbaceous plants in different agricultural habitats

SUN Yufang, CHEN Baoxiong, JIN Bin, ZHU Shenghai, ZHANG Songbai, ZHANG Hongbin, LI Yaokui, LIU Yunhui, DUAN Meichun

2019, 27(11): 1617-1625. doi: 10.13930/j.cnki.cjea.190549

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Abstract:
Organic agriculture is conducive to increasing plant diversity in farmland, and rich plant communities can provide animals with a range of services, including sources of pollen for honey, host, and habitats. Although there have been many studies of the effect of organic management on plant α diversity in single farmland habitat, little research into β and γ diversity has been conducted. In this study, a large area of organically managed farmland and a nearby conventionally managed farmland with multi-habitats were selected, and the differences in the α, β, and γ diversity of herbaceous plants between two management practices and among different habitat types were studied. In both cases, the farmland habitats included vegetable greenhouse, orchard, open-air field, field boundary, and paddy ridge. The herb plant survey was conducted at the start of summer. Findings from ANOVA revealed that, though the average number of local herb plants and medicinal herb plants (α diversity) was significantly higher in all habitats in organic farmland than the case in conventional farmland, organic management only increased the number of herb plant and medicinal herb plant species in open-air field and the number of medicinal herb plant species in paddy ridge. The impact of organic management on other habitats was not significant. Under conventional management, there were no significant differences in the number of plant species among five habitat types. However, under organic management, the number of herb plant species in open-air field and medicinal herb plant species in paddy ridge were significantly higher than those in vegetable greenhouse. Results of non-metric multi-dimensional analysis based on the Manhattan index indicated that, although there was no difference in the overall species composition (β diversity) of organically managed farmland and conventionally managed farmland, there were significant differences between organic management and conventional management in the herb plant and medicinal herb plant species compositions of open-air field and paddy ridge. β diversity was higher in organic farmland than in conventional farmland, and relatively independent plant communities formed in different habitats. A rarefaction curve of species richness indicated that, although the total number of herb plant species and the number of medicinal herb species (γ diversity) in organically managed farmland were higher than those in conventionally managed farmland, the difference was not significant statistically. Organic management increased the α diversity and β diversity of herbaceous plants in both paddy ridge and open-air field, but there was no obviously beneficial effect of organic management in vegetable greenhouse, field boundary, and orchard. The increase in local α diversity and β diversity did not necessarily result in a significant increase in γ diversity. In summary, it cannot be concluded universally that organic agriculture can increase plant diversity in different habitats and at different spatial scales. It is necessary to specifically consider the differences in different habitats and diversity indices at different spatial scales. Longer implementation of organic management, low-frequency weeding, and artificial increases in the pool of local plant species can help increase herbaceous plant diversity of the entire region and in all habitat types.

Research progress of ecological space and ecological land in China

FEI Jianbo, XIA Jianguo, HU Jia, SHU Xiangyang, WU Xi, LI Jun

2019, 27(11): 1626-1636. doi: 10.13930/j.cnki.cjea.190371

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Abstract:
Ecological space and ecological land are important components of land space and are interdisciplinary research topics in the domains of geography, landscape ecology, and applied ecology. However, in China, there is considerable controversy regarding the connotations of these two components, and there is both confusion and error in the relevant researches and its applications. Based on analysis of domestic literatures concerning ecological space and ecological land, this paper defined both concepts, studied their logical relationship, and examined the research progresses and limitations of the two concepts. Currently, domestic researches on ecological space and ecological land suffered from the following problems:understanding of the connotations of the concepts was still not unified, the identification methods and classification systems were still not perfect, and the research focused on urban areas. The research method focused on the use of spatial analysis and optimization models, and the application of multiple methods, such as psychological perception and social investigation, was lacking. In the new era, along with the new requirements for ecological civilization construction and a rural revitalization strategy, this paper proposed that future studies should focus on rural ecological space and ecological land. Researchers should concentrate on establishing an identification method, a classification system, an evaluation system, and a protection and utilization mechanism governed by the demands of science of sustainability and with human well-being at its core.

Temporal and spatial variation and driving factors of farmland ecological service value in Chongqing

KONG Fanjing, CHEN Yucheng, CHEN Qinghua, MOU Qinjie, YAN Jianzhong

2019, 27(11): 1637-1648. doi: 10.13930/j.cnki.cjea.190192

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Abstract:
Farmland plays an irreplaceable role in ensuring the supply of materials and of ecosystem services. In this study, we aimed to explore the regional farmland ecological service value in terms of spatial and temporal changes as well as driving factors, based on the statistical yearbook of Chongqing from 2007 to 2016 and the counterpart annual data of the districts and counties in Chongqing in the relevant years. We constructed a farmland ecological service value index system, evaluated the farmland ecological service value in Chongqing based on the price index and tabulation and list method, and analyzed the social driving factors contributing to the difference in per capita farmland ecological service value among districts and counties in Chongqing using the STIRPAT model. The results showed that the values of farmland ecological services in Chongqing in 2007, 2012 and 2016 were ￥89.80 billion, ￥93.89 billion and ￥103.84 billion, respectively. The farmland ecological service value showed an evident upward trend with an increase rate of 15.63%. The 10-year mean farmland positive service value (￥102.45 billion) was considerably higher than its negative value (￥5.90 billion). In terms of the temporal change of farmland ecological services value, the total amount and per capita difference in the west of Chongqing were the most significant (30.32% and 16.80%, respectively). In the west of Chongqing, the farmland negative value of the Yongchuan and Jiangjin Districts, where agriculture is more developed, was relatively prominent. The farmland ecological service value ranked as follows:southeast of Chongqing (￥5 855 per person) > northeast of Chongqing (￥4 027 per person) > west of Chongqing (￥3 846 per person) > center of Chongqing (￥40 per person). The agricultural population, urbanization rate and energy consumption per ￥10 000 of GDP were the social driving factors attributable for the spatial difference of the per capita farmland ecological service value in all districts and counties of Chongqing. Development of the main city area had exerted a substantial pressure on its farmland ecosystem. The industry structure in this area should be rationally adjusted to improve the farmland ecological service value. The research results provide a scientific basis for the ecological environment protection, restoration, and compensation of farmland in Chongqing.

Impact of soil warming on the activity and abundance of nitrifiers under nitrogen fertilization conditions

Tatoba R Waghmode, ZHANG Xinyuan, DONG Wenxu, ZHANG Chuang, HU Chunsheng

2019, 27(11): 1649-1655. doi: 10.13930/j.cnki.cjea.190166

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Abstract:
The first step of nitrification (i.e., the oxidation of ammonia to nitrate) is catalyzed by nitrifiers, such as ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA). However, the impact of soil warming on the activity and abundance of nitrifiers under different nitrogen (N) fertilization conditions remains poorly understood. A long-term field warming experiment has been conducted since October 2008 at the Luancheng Agro-Ecosystem Experimental Station of Chinese Academy of Sciences in the North China Plain, during which soil temperature was increased by 1.5℃ using infrared heaters (power, 1 000 W) placed 2 m above the soil surface. In 2018, we investigated soils from the control (no warming) and warming treatment plots for potential nitrification rate (PNR), abundance of AOB and AOA at 10 cm and 20 cm soil depth under two N fertilization conditions:without N fertilization (N0) and with 240 kg(N)·hm^-2·a^-1 fertilization (N1). Soil PNR, nitrate (NO₃^--N), and ammonium (NH₄⁺-N) contents were spectrophotometrically assessed, and the abundance of functional genes was investigated via real-time quantitative PCR. Warming increased PNR and NO₃^--N content under N1 treatment and decreased them under N0 treatment (P < 0.05). Moreover, warming significantly increased AOB abundance under N1 treatment (P < 0.05), whereas it decreased the abundance of both AOA and AOB under N0 treatment, at both soil depths. Compared with N0, N1 exhibited substantial decrease in AOA/AOB ratio, suggesting that compared with warming without N fertilization, warming with N fertilization exhibited higher stimulation of AOB growth than of AOA growth. Conclusively, this study suggests that AOB significantly and positively responded to warming with N fertilization, whereas both AOA and AOB significantly and negatively responded to warming without N fertilization. This study provides an understanding of nitrifier activity and the response of ammonia-oxidizing microorganisms to warming conditions and N availability.

Cadmium transfer in the ecosystem of soil-wheat-aphid under dual stress of cadmium and drought

SHU Qihao, KONG Yanyan, LUO Kun, LI Yuan, ZHAO Huiyan

2019, 27(11): 1656-1662. doi: 10.13930/j.cnki.cjea.190324

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There have been several reports regarding the effects of both drought and heavy metals on aphids. However, although aphids often experience dual stresses and even multiple stresses, such as a combination of heavy metals, drought, and other stress factors, in the natural environment, there have been few reports on dual or multiple stresses. To explore the effects of dual stresses from drought and heavy metal on the Cd transfer in the soil-wheat-aphid system, this study took Sitobion avenae (Fabricius) as the research object and used an atomic absorption spectrophotometer to measure the Cd contents of S. avenae and of the roots and leaves of wheat following treatment with different soil contents of heavy metals (100 and 200 mg·kg^-1) and exposure to different degrees of drought stress (well-watered, moderate drought stress and severe drought stress). The results revealed that both soil Cd content and drought stress had significant effects on the Cd contents of both wheat and aphids (P < 0.05). The interactive effect of soil Cd content and drought stress was significant (P < 0.05) on Cd content of wheat roots and leaves, but it was not significant (P > 0.05) on Cd content of wheat stems and aphids. Cd accumulation in wheat was in the order of root > stem > leaves, under the same stress conditions. As drought stress increased, the Cd content of wheat roots and the Cd transfer coefficient from soil to roots gradually decreased, and the stem Cd content and transfer coefficient from roots to stems gradually increased. In S. avenae, the Cd content under 100 mg·kg^-1 soil Cd content was higher than that under 200 mg·kg^-1. Moderate drought stress increased Cd accumulation in the bodies of the aphids, whereas severe drought stress reduced the Cd accumulation. The Cd transfer coefficient from leaf to aphid was >1, and significantly larger than that from soil to root and that from root to stem and stem to leaf, indicating biomagnification of Cd in the aphids. In summary, drought stress promotes the transfer of Cd from soil to stems of wheat and its accumulation in roots, but it inhibits the transfer of Cd from root to stem and its accumulation in stem. Moderate drought stress promotes Cd accumulation in S. avenae, whereas severe drought stress inhibits Cd accumulation in aphid.

Soil tillage practices affecting the soil characteristics and yield of winter wheat and summer maize in North China

GUAN Jiexi, CHEN Suying, SHAO Liwei, ZHANG Yuming, ZHANG Xiying, LU Yang, YAN Zongzheng

2019, 27(11): 1663-1672. doi: 10.13930/j.cnki.cjea.190246

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Abstract:
The North China Plain (NCP) is one of the most intensively farmed agricultural regions in China, with approximately 70% of the total cultivated land being used for an annual double-cropping system of winter wheat and summer maize. Owing to the long-term rotary and no tillage practices accompanying with the whole straw of winter wheat and summer maize return to field for several years, soil physical characteristics are gradually changing in terms of the increased soil pan depth, bulk density and content of soil nutrients in the surface soil layer. Improving soil quality by changing the tillage practices might help to maintain crop productivity in this region. An experiment was conducted for the winter wheat-summer maize rotation system in Luancheng County, which represented a high yield region, and in Nanpi County, which represented a medium and low yield region, in the NCP. Four treatments-soil deep tillage (DT), subsoiling (SS), narrow subsoiling (NSS), and rotary tillage (control, CK)-before winter wheat sowing and no tillage before summer maize sowing to all treatments were simultaneously conducted at the two areas. Soil bulk density, crop root growth, soil water use, yield and water use efficiency (WUE) were monitored throughout. Results showed that the effects of different tillage practices on soil and crop were different in the two regions. At Nanpi, deep tillage and subsoiling significantly increased crop yield. Compared with traditional rotary tillage, winter wheat yield was improved by 16.5% under DT, 19.3% under SS, and 13.1% under NSS. Yield of summer maize was increased by 17.3%, 16.2%, and 21.9%, respectively, with annual yield increases of 16.9%, 17.6% and 17.8%, respectively. Yield differences were not observed among the DT, SS, and NSS treatments. However, no significant difference in crop yield among the four treatments was found at Luancheng. Furthermore, four tillage practices reduced soil penetration resistance and bulk density for the 0-20-cm soil layer in both Luancheng and Nanpi. At Nanpi, after sowing winter wheat, the soil penetration resistance of the 0-20-cm soil layer under DT, SS, NSS and CK decreased by 69.7%, 72.7%, 72.5% and 68.2%, respectively. At Luancheng, soil penetration resistance of the 0-20-cm soil layer was reduced by 88.8% averagely under treatments of deep tillage and subsoiling, and slightly increased by 7.7% under CK. Soil bulk density of the 0-40-cm soil layer under the four tillage treatments were all lower at wheat harvest compared with that before tillage. Until the summer maize harvest, soil bulk density under different tillage treatments was essentially similar to that before tillage, and there was no significant difference among the four tillage treatments. At Nanpi, WUE of winter wheat and summer maize was significantly increased under DT, SS, and NSS compared with that under CK. At Luancheng, the WUE of winter wheat and summer maize was similar among the four treatments. These results indicated that different tillage practices in the low yield regions benefited crop production and water productivity. However, in the high yield regions, the three tillage practices did not enhance crop performance compared with traditional tillage practice. Therefore, it is suggested that the model of soil rotary tillage can be continuously implemented in the high yield regions of the NCP, whereas DT can be beneficially implemented in the medium and low yield regions.

Effects of tillage methods on soil physical properties and spatial distribution of flue-cured tobacco (Nicotiana tabacum) roots in mountainous tobacco fields

LIU Qi, WANG Jinjun, FENG Xingbing, ZHANG Liuchen, DENG Xiaopeng, MA Erdeng, TONG Wenjie

2019, 27(11): 1673-1681. doi: 10.13930/j.cnki.cjea.190316

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Abstract:
To explore the effects of different tillage methods on the yield and output value of flue-cured tobacco (Nicotiana tabacum) in mountainous tobacco fields and to reveal how deep tillage and subsoiling in mountainous tobacco fields increases yield and efficiency, a field experiment was conducted, and soil physical characteristics, soil water content, spatial distribution of the tobacco root system, and the growth of tobacco plants were investigated. A flue-cured tobacco variety, 'K326', was planted and subjected to tillage methods of 20 cm of rotary tillage (control, RT20), 30 cm of deep tillage (DT30), and 30 cm (ST30) and 40 cm (ST40) of subsoiling tillage. The results showed that DT30, ST30, and ST40 significantly increased the yield and output of the flue-cured tobacco when compared with RT20. The yield was increased by 12.2%, 12.3% and 16.0%, meanwhile the output was increased by 10.5%, 13.8%, and 21.8% under DT30, ST30, and ST40 treatments, respectively. Moreover, deep tillage and subsoiling tillage significantly improved the physical structure of soil subsurface layer in the range of 20-40 cm. The soil bulk density was decreased by DT30, ST30, and ST40 treatments; the soil bulk density values under DT30, ST30, and ST40 treatments were 6.1%, 5.3%, and 8.0% lower than that of RT20 treatment, respectively. However, the treatments increased the capillary porosity of the soil; capillary porosity values under those three treatments were 11.3%, 13.1%, and 21.6% higher than that under RT20 treatment, respectively. Additionally, the soil water content of the 20-40-cm soil layer was also increased by 4.9%, 2.3%, and 5.7% under DT30, ST30, and ST40 treatments compared with RT20 treatment, respectively, when measured at the rosette stage. At the budding stage, it was still increased by 4.5%, 3.8%, and 5.6% under DT30, ST30, and ST40 treatments over RT20 treatment, respectively. Deep tillage and subsoiling tillage treatments increased the absolute fresh weight and promoted vertical growth of tobacco roots as well as alleviated the crowding of the upper roots. The DT30, ST30, and ST40 treatments increased the root depth index by 5.32%, 8.26%, and 16.20% compared with RT20 treatment, respectively. The difference in the fresh weight of the tobacco roots was the most significant among different treatments of soil subsurface (depth of 20-40 cm). Among them, the fresh weight of tobacco roots in the 20-30-cm soil layer with deep ploughing and deep loosening measures was 162.2%-469.0% higher than that with the control, and in the 30-40-cm soil layer it was 56.5%-292.9% higher. It also turned out that subsoiling and deep tillage improved soil physical properties such as soil bulk density, porosity, and moisture in mountainous tobacco fields, which enhanced the soil environment for tobacco planting and benefited tobacco root growth. These treatments also allowed for optimization of the horizontal and vertical distribution of the tobacco root system. Furthermore, these tillage treatments significantly increased the dry matter of flue-cured tobacco, which resulted in increased yield and output value of tobacco.

Effects of nitrogen application methodologies on yield and nitrogen use efficiencies in a summer maize (Zea mays)-winter wheat (Triticum aestivum) rotation system

LI Lantao, REN Li, YIN Huanli, GUO Ya, WANG Haibiao, ZHANG Qian, WANG Yilun

2019, 27(11): 1682-1694. doi: 10.13930/j.cnki.cjea.190223

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Abstract:
This research was conducted to explore an appropriate nitrogen (N) management pattern for a summer maize (Zea mays)-winter wheat (Triticum aestivum) rotation system (SM-WW) and to study the effects of N application methodologies on crop yields and N use efficiencies in a SM-WW in high and medium yield areas of Henan Province, North China. An appropriate N management strategy was analyzed and established in this study. The detailed N application strategies for the SM-WW were as follows:(i) no N application (T1); (ii) one-off application of urea with the rate of 210 kg(N)·hm^-2 (T2); (iii) fractional application of urea with the rate of 210 kg(N)·hm^-2 (T3); (iv) combined application of controlled-release N fertilizer with urea at the rate of 180 kg (N)·hm^-2 for wheat and 195 kg (N)·hm^-2 for maize (T4); (v) combined application of controlled-release N fertilizer with urea at the rate of 210 kg(N)·hm^-2 for wheat and maize (T5). The Soil-Plant Analyses Development (SPAD) chlorophyll meter (Minolta Camera Co., Japan) was used to determine SPAD values. Plant and/or grain N content and biomass were measured at different growth stages for the SM-WW and used to calculate different N indicators. Results showed that N fertilization methodologies could significantly affect the yield, yield components, and N indicators among the five treatments, with the overall trend being T5 > T4 > T3 > T2 > T1. Moreover, the yield and N parameters in high-yield area were significantly higher than those in medium-yield area. Compared with the medium-yield condition, the average values among the five treatments for yield, plant N content, and accumulation increased by 58.0%, 19.2%, and 47.1% for maize and 34.7%, 33.3%, and 85.9% for wheat, respectively, under high-yield conditions. Regarding the N use efficiencies, from T1 to T5, apparent N use efficiency, agronomic N use efficiency, and N absorption amount for producing 100 kg of grain were increased both in the high-and medium-yield areas. However, the opposite trend was found for N harvest index. The results showed that an optimal N fertilization treatment, such as T4 or T5, had great potential in improving N use efficiency without adversely affecting grain yield and could be an appropriate model of N nutrient application during the SM-WW in Henan Province, China.

Effects of mixed application of biological organic fertilizer and Yellow River sediment on the sink-source relationship of winter wheat in saline-alkaline soil

LI Xiaoshuang, DANG Hongkai, SONG Ni, SHEN Xiaojun, SUN Jingsheng

2019, 27(11): 1695-1705. doi: 10.13930/j.cnki.cjea.190333

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Abstract:
To study the source and sink characteristics and the transformation of both source and sink of winter wheat in saline-alkali soil, we conducted an experiment in Nanpi County, China, during the winter wheat growing seasons from 2015 to 2018. The positioning monitoring test was employed in the study. The study involved four processes:biological organic fertilizer application (FF), mixing Yellow River sediment (SS), FF and SS combination (SF), and blank (CK) treatment as control. Wheat varietiy 'Xiaoyan 60' was used in the field as the experimental material, and the growth parameters and grain yield of the wheat were monitored during the growth period. The findings revealed that there was a gradual downward trend in the photosynthetic rate (P_n) of flag leaves after anthesis under different treatments. The order of flag leaves P_n was SF > FF > SS > CK from anthesis to 20 d after anthesis. SF, FF, and SS were averagely 55.08%, 27.32%, and 1.88% higher, respectively, than CK. As for the growth process, the leaf area duration showed a single peak curve, with the peak appearing at the boot-anthesis stage. After 30 days of anthesis, there was a rapid decline in leaf area duration, and the photosynthetic potential of the treatments was SF > FF > SS > CK. At the boot-anthesis stage, the photosynthetic potentials of SF, FF, and SS were increased by 29.02%, 18.79%, and 10.62% respectively, compared with CK. Moreover, their total photosynthetic potentials after anthesis were 41.66%, 24.72%, and 13.94% higher, respectively, than that of CK. The source productivity capacity of SF was the highest during the whole growth period, before and after anthesis, at 34.06%, 40.52%, and 28.15% higher respectively, than that of CK. SF had the highest storage indexes, including panicle number, total grain number, maximum potential storage capacity and effective storage capacity; these were averagely 25.69%, 30.00%, 42.06%, and 38.84% higher, respectively, than in CK. The source-sink relationship indexes of SF were all the highest. They were yield, conversion rate of source production capacity after anthesis, grain/leaf ratio, and economic coefficient; these were 41.08%, 9.53%, 8.50%, and 4.01%, higher, respectively, than with CK. In this study, the effective storage capacity showed significantly positive correlation with the total number of spikes and the total number of grain, and these were the key factors affecting winter wheat yield in saline-alkali soil. The way of mixing Yellow River sediment or applying bio-organic fertilizer could improve the photosynthetic performance of wheat, improve the production capacity of the source, and promote the transformation of the source-sink. The best treatment was the SF treatment, which combined SS and FF application. This treatment combines the advantages of both, and was more conducive to the improvement and sustainable development and utilization of coastal saline and alkaline soil.

Characteristics of nitrogen accumulation and utilization in peanuts (Arachis hypogaea) with different nitrogen use efficiencies

WANG Chunxiao, LING Fei, LU Zeqi, JIANG Wei, ZANG Hongwei, ZHANG Wei, YAO Jie, LAN Feng, LIU Xuan, WANG Zhixin, ZHENG Yongmei

2019, 27(11): 1706-1713. doi: 10.13930/j.cnki.cjea.190239

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Enhancing nitrogen (N) use efficiency at a genetic level would be an effective way to reduce N use and strive toward green cultivation. Understanding the N use characteristics of different peanut (Arachis hypogaea) varieties could provide some valuable insight for selecting and breeding peanut varieties with high N use efficiency and reduce applied N use in cultivation. In total, 19 peanut varieties were used to investigate the N accumulation and utilization characteristics under different N use efficiency conditions of varieties with differing yield potentials in a pot experiment via ¹⁵N isotope tracing analysis. Based on the average yields and N use efficiencies, the 19 peanut varieties were divided into the following four types:high yield and high N use efficiency (HYHN), high yield and low N use efficiency (HYLN), low yield and high N use efficiency (LYHN), and low yield and low N use efficiency (LYLN). The results showed that there were significant differences in different peanut varieties. The varieties with moderate N content in the vegetative organs were conducive to a simultaneous increase in the yield and N use efficiency, while no significant differences were detected in the N content of the reproductive organs or whole plants across various peanut varieties. Increases in the N allocation rates in reproductive organs were characteristic of the HYHN varieties under the assumption that there was sufficient N accumulation in the peanut plants. The results also showed that the available N levels and N use efficiencies of the soil's N source and fertilizer's N source were consistent in various peanut varieties, whereas different yields among the varieties determined the fixed N from the N source at nodulation. In addition, under similar N use efficiency conditions, a higher N-fixing nodule level favored increased yield. The N supplying from the soil's N source increased in the high-N type varieties compared with that in the low-N type varieties; however, it was the opposite with regards to the fixed N source at nodulation. This showed that were desirable compensatory effects between the soil's N and fixed N sources. Meanwhile, there were no significant differences in the N supplying ratios with regards to the fertilizer's N source in various varieties. The yields and N use efficiencies of different varieties were highly consistent with the N use efficiency and partial productivity of the N fertilizer, whereas there were negligible differences in the N use efficiencies among various peanut varieties. In conclusion, there were significant differences among different peanut varieties with respect to the yield and N use efficiency. Breeding a HYHN peanut variety is of great importance and appears feasible. This is an effective method to decrease the N use in peanut cultivation in the future.

Radiation use efficiency and its classification of main varieties in double-cropping rice region of South China

HUANG Nongrong, FU Youqiang, ZHONG Xuhua, LIANG Kaiming, PAN Junfeng, LIU Yanzhuo, HU Xiangyu, PENG Bilin, CHEN Rongbin, HU Rui

2019, 27(11): 1714-1724. doi: 10.13930/j.cnki.cjea.190396

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Radiation use efficiency (RUE) of rice varieties is an important factor influencing grain yields of double-cropping rice in South China. However, there have been few studies of rice RUE and its relationship to agronomic traits. We conducted two-season field experiments to evaluate the RUE of 36 major rice varieties in a double-cropping rice region of South China. The relationships between RUE and the main agronomic traits (for example, yield) were explored, and the clustering analysis of tested varieties were classified. The findings revealed highly significant difference of RUE existed in different rice varieties and cropping seasons, respectively. In early and late seasons, RUEs were significantly and positively correlated with the grain yield, the harvest index, and the 1000-grain weight. In the early season, RUE was significantly positively correlated with the biomass and significantly negatively correlated with the growth period; however, in the late season, these correlations were not significant. Principal component analysis revealed the 12 agronomic traits of the tested varieties to be compressed to four independent comprehensive indexes, including the yield and light energy efficiency factor, the panicle and grain number factor, the growth period and grain weight factor, and the seed setting rate factor, in the early season; and to five independent comprehensive indexes, including the yield and light energy efficiency factor, the panicle and grain number factor, the biomass factor, the growth period and grain weight factor, and the seed setting rate factor, in the late season. Clustering analysis revealed that the varieties tested in this study could be divided into three groups:low RUE, medium RUE, and high RUE. Rice varieties numbers with low RUE, medium RUE, and high RUE accounted for 50.0%, 38.9%, and 11.1%, respectively, of the total numbers of tested varieties in the early season and for 27.8%, 47.2%, and 25.0%, respectively of the total numbers in the late season. 'Yliangyou 143' 'Teyou 524' 'Tianyou3301' and 'Teyou3301' were identified as high-RUE varieties in the early season, and 'Wuyou308' 'Tianyou3618' 'Wuyou163' 'Wuyou376' 'Tianyou998' 'Tianyouhuazhan' 'Tianyou3301' 'guang8you188' and 'Yliang you 305' were identified as high-RUE varieties in the late season in South China. In our study, the classification of RUE types for rice varieties has been reported for the first time. The findings will have important guiding significance for the variety layout in growing areas and both the breeding of high-RUE varieties and their efficient utilization.

Distribution characteristics and sources of nitrate in the unsaturated zone and groundwater of farmlands in an area irrigated with reclaimed water

DUN Yu, ZHANG Han, YANG Zhenglun, TANG Changyuan, ZHANG Zhaoji

2019, 27(11): 1725-1731. doi: 10.13930/j.cnki.cjea.190578

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The present study aimed to presenting the source and environmental behavior of nitrate in various environmental media by sampling and analyzing the soil in the unsaturated zone, surface water, and groundwater of a typical area irrigated with reclaimed water in the North China Plain. This study also identified the sources of groundwater nitrate pollution in the area, and determined the effects of different irrigation conditions on nitrate migration in the soil in the unsaturated zone. In the Xiao River basin, which is seriously affected by reclaimed urban water, nitrate concentrations in groundwater ranged from 4.0 mg·L^-1 to 156.6 mg·L^-1, nitrate in the groundwater had formed a high-value area of 2 km from the river channel and 70 m in depth. And nitrate moved down 1-2 m every year. The correlation between nitrate and chloride ion indicated that reclaimed urban water was the main source of nitrate in the unsaturated zone, surface water, and groundwater of the area irrigated with reclaimed water. Geoprobe system was used to obtain continuous soil core samples from the typical unsaturated zones to study the influence of reclaimed water on the vertical distribution of NO₃^--N in thick unsaturated zone. The average contents of NO₃^--N in the reclaimed water and groundwater irrigation areas were 137.0 mg·kg^-1 and 107.7 mg·kg^-1, with the peak values of 523.2 mg·kg^-1 at a soil depth of 1.20 m and 725.9 mg·kg^-1 at a depth of 0.85 m, respectively. The correlation analysis between soil nitrate and chloride ion indicated that the NO₃^--N in the reclaimed water irrigation area was mainly affected by reclaimed urban water, whereas in the groundwater irrigation area it may because the use of agricultural nitrogen fertilizers. By comprehensively analyzing the relationship between groundwater age and nitric acid, the historical process of the nitrogen source causing the groundwater nitrate pollution could be reproduced on a time scale. Under the unique hydrogeological background of the North China Plain, the nonpoint source pollution of the farmland has a limited effect on groundwater pollution, while the risk of groundwater nitrate nitrogen pollution is relatively high around the reclaimed water river.

Effects of different biomass amendments on soil organic carbon characteristics in alpine desertification grassland of Northwest Sichuan

ZHANG Xiaoli, KONG Fanlei, LIU Xiaolin, HU Lifeng, LI Yuyi

2019, 27(11): 1732-1743. doi: 10.13930/j.cnki.cjea.190248

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Abstract:
The special geographical environment, climatic conditions, and excessive artificial grazing in the alpine grassland of northwestern Sichuan have caused grassland desertification. To examine the effects of different biomass amendments on the soil organic carbon composition and respiration characteristics in alpine desertification grassland, we adopted a randomized block test design method and two factors field trials for setting biomass amendments and their application rates. The biomass amendments used were three kinds of straw (JG), slag (JZ), and biochar (SWT). The application rates were 6 t·hm^-2 (JG1, JZ1, SWT1) and 18 t·hm^-2 (JG3, JZ3, SWT3). We used blank treatment (CK) as a control to examine the effects of the different amendments on the total organic carbon, the activated organic carbon, and the respiratory characteristics in desertified soil. The findings demonstrated that:1) application of the biomass amendments significantly increased the contents of soil organic carbon (TOC), microbial biomass carbon (MBC), and easily oxidized organic carbon (EOC), which became more obvious as the amounts of amendments were increased. Compared with CK, the organic carbon in the 0-10 cm soil layer increased averagely by 60.66%, 39.22%, and 34.99% with JG, JZ and SWT treatments, respectively; the soil MBC content was expressed as JZ > JG > SWT in the 0-10 cm soil layer, and the difference among treatments were significant. EOC content was the highest in JG treatment; in the 0-10 cm and 10-20 cm soil layers, it was increased averagely by 108.82% and 79.26%, respectively, compared with CK. 2) Under different biomass amendments, EOC/TOC revealed that JG > JZ > SWT > CK, MBC/TOC revealed that JZ > JG > SWT > CK, and the differences among treatments were significant. 3) The application of different amendments increased the soil respiration rate significantly in proportion to the increased application rate of the amendment. Compared with CK, the soil respiration rates of JG1, JZ1, and SWT1 treatments increased by 103.42%, 86.31%, and 18.83%, respectively. The soil respiration rates were significantly higher under JZ and JG treatments compared with SWT and CK treatments. Correlation analysis revealed significant positive correlation of the soil respiration rate with soil water (P < 0.05), and significant positive correlations with organic carbon, MBC, and EOC (P < 0.01). 4) The application of different biomass amendments significantly increased soil respiration, soil microbial respiration, and net ecosystem productivity (NEP), both of which showed strong carbon sink potential. Under JG treatment, the NEP value was significantly higher than that under JZ and SWT treatments, by 56.45% and 122.12%, respectively, and there were significant differences among treatments. These findings suggested that the straw improver had higher carbon sink strength. This study can provide a basis for the development of scientific and effective soil carbon regulation and management measures for improving alpine grassland desertification soil in the northwestern Sichuan Basin in China.

Effect of composite soil improvement agents on soil amendment and salt reduction in coastal saline soil

ZHANG Xiaodong, LI Bing, LIU Guangming, SUN Jianping, LU Xuelin, WANG Xiuping

2019, 27(11): 1744-1754. doi: 10.13930/j.cnki.cjea.190001

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Abstract:
The aim of this study was to develop a rapid, low-cost method to desalinate muddy coastal saline soil to facilitate its use for economic crops. We used composite improvers (phosphogypsum, dung, humic acid, and corn straw), comprehensive agronomic measures (deep tillage, shallow soil improvement, high ridge cultivation, and drip irrigation), biological measures (step planting of salt-tolerant plants), and adopted L₁₆(4⁵) orthogonal design, and fuzzy mathematic evaluation to systematically analyze the effects of composite improvers on soil amelioration, salt reduction, and Abelmoschus manihot (L.) Medic yield. The total effect of each composite improver was comprehensively evaluated, and the preferred improvers suitable for application on coastal muddy saline soil were determined. Results showed that composite improvers with a capital cost of 2.55-6.01 ￥·m^-2 significantly reduced soil salt content when used with comprehensive agronomic measures consisting of 40 cm of tillage, 30 cm of soil improvement, 15 cm of ridge, drip irrigation controlled to -10 kPa of soil potential, and Sesbania cannabina (Retz.) Poir used as the fore-rotating plant. Soil salt content decreased from 10.86 g·kg^-1 to < 2.0 g·kg^-1 in the 0-10 cm soil layer and to < 2.5 g·kg^-1 in 10-20 cm layer. Soil organic matter content increased to >12 g·kg^-1; there were significant increases in alkali-hydrolyzed nitrogen and available phosphorus, and the soil macroaggregate content was 2.41-7.62 times higher than that of the control. The proper combinations of composite improvers for heavy saline silt soil were screened based on the comprehensive evaluation of soil salt content, pH, organic matter, alkali-hydrolyzed nitrogen, available phosphorus, available potassium, and micro-aggregates. A combination of 22 500 kg·hm^-2 phosphogypsum + 105 m³·hm^-2 organic fertilizer + 3 750 kg·hm^-2 humic acid + 45 m³·hm^-2 maize straw provided the optimum effect on the improvement of coastal saline soil. Soil organic matter and alkali-hydrolyzed nitrogen increased by 181.87% and 130.52%, respectively, whereas the capital cost was only 4.05 ￥·m^-2. Two other combinations provided suboptimal results:15 000 kg·hm^-2 phosphogypsum + 75 m³·hm^-2 organic fertilizer +3750 kg·hm^-2 humic acid +135 m³·hm^-2 maize straw (capital cost 4.48￥·m^-2); and 30000 kg·hm^-2 phosphogypsum +5 m³·hm^-2 organic fertilizer +2250 kg·hm^-2 humic acid +135 m³·hm^-2 maize straw (capital cost 5.02 ￥·m^-2).

Correlation analyses among terrains diversity, soil types diversity, and dynamic change in arable land

LI Xiaoying, ZHANG Xuelei, REN Yuanyuan

2019, 27(11): 1755-1766. doi: 10.13930/j.cnki.cjea.190272

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Abstract:
Soil diversity research has been a major focus of the soil science research community since the start of the 21st century. In recent years, some scholars have initiated research on diversity in land resources, water bodies, topographies, and parent materials, which has broadened the field of diversity studies. The exploration of the diversity in arable land is limited. This study focuses on the use of spatial data information to explore the regional diversity and differences of various geo-elements in arable land. Three typical research areas in northern, central, and southern regions of Henan Province, respectively, were selected to calculate the dynamic change (2001, 2007, and 2017) in arable land over time based on the topographic and soil conditions at the scale of 1 km×1 km, 3 km×3 km, and 5 km×5 km grids. And the correlation index was determined using the ArcGIS and SPSS softwares in combination with the correlation analysis method. The purpose of this analysis was to provide a new research perspective on the driving force of the dynamic change in arable land resources and guide their future rational use. The results showed that, first, the diversity of topographic components in the northern and central Henan regions was similar, whereas that in the southern Henan region was relatively unvarying. The terrain's spatial distribution diversity of each study area was plain > hill > mountain. Second, the soil composition in the southern Henan region was the most homogeneous and abundant, and it was relatively uniform in central Henan. The typical soil was different in each study area, but its distribution was uniform overall. Third, an important factor influencing the diversity of terrain and soil spatial distribution is at what scale it is measured, and the 3 km×3 km grid was suggested as the most suitable research scale. Fourth, the spatial distribution diversity index of the soil and terrain containing arable land changed the area spatial distribution and had obvious relevance. Among the three regions, the plains in the topography had a high correlation of approximately 0.95. In addition, the correlation between the typical soil (such as paddy soil in southern Henan, cinnamon soil in southern and northern Henan, and fluvo-aquic soil in northern Henan) and difference in the arable land within each study area was more discernable, reaching over 0.9. Overall, the compositional diversity and spatial distribution pattern of the topography and soil factors were significantly different in the representative study areas. Using a different grid scale, the difference in the arable land area is closely related to the spatial distribution diversity index of the topography and soil factors.

Ecological security pattern of land use in a typical transect of Hebei Province

YUAN Dapeng, CHEN Qile, SHI Yao, LI Jinpu, WANG Shutao

2019, 27(11): 1767-1778. doi: 10.13930/j.cnki.cjea.190247

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Abstract:
The "Planning Outline of Hebei Xiong'an New District", which has been published recently in full text, states that it is necessary to adhere to the priority of ecological protection and build an ecological corridor taking in "Taihang Mountain Range-Bohai Bay", and "Jingnan Ecological Green Wedge-Juma River-Baiyangdian". In view of this, this paper referred to the principle and basis of land sample selection, laid out the typical sample belt of Hebei Province, and used the minimum cumulative resistance model, with the forest land, grassland and wetland of the sample belt as the ecological source land, and the artificial surface as the source of urban expansion. In terms of attributes and external attributes, five indicators-elevation, land landscape type, soil type, ecological sensitivity, and ecosystem service value-have been selected to investigate the ecological security pattern of land use. The findings were as follows:five ecological safety areas were designated for the typical sample area in Hebei Province; these were ecological core area, ecological buffer area, ecological transition area, ecological occupation area, and ecological management area. The spatial pattern distribution of ecological source areas and urban expansion sources showed clear boundaries, all of which were concentrated and contiguous, though the ecological connectivity was weak. The ecological core area, which was the core area of the nature reserve, was at least 1 082.42 km². The buffer area, which was the medium connecting the upper, middle and lower reaches, was as much as 6 943.63 km². This area should be used rationally for protection. The ecological transition area, which was the key area for the development and construction of the reserve following the urban and rural construction, was 3 189.25 km². The ecological occupation area, with an area of 5 835.34 km², was distributed in the ecological transition area and the ecological governance zone. It was the main area of urban construction and economic development. The ecological management area was 1 710.70 km²; it was primarily an ecologically fragile area and was a key region for ecological restoration and future ecological industry development. In summary, There should be a large-scale planting of the ecological core area and the ecological buffer zone. The ecological transition area should be controlled strictly to expand to the ecological land, and the ecological occupation area should be developed according to the needs of the urban population and the economy. It is necessary to return farmland to the lake to restore the water surface, strictly to the soil environmental safety bottom line, and optimize the ecological safety barrier system.

2019 Vol. 27, No. 11