2022 Vol. 30, No. 12

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Agroecosystem and Its Management
Plant mediated interaction between aboveground and underground herbivores under drought stress
SHU Yuan, JU Jing, ZHAO Haitao, HAO Yanbin, LI Linfeng
2022, 30(12): 1891-1899. doi: 10.12357/cjea.20220140
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With global climate change, the frequency and intensity of drought events may increase. Therefore, it is crucial to predict the net impact of global climate change on ecosystems by studying the interaction between aboveground and underground phytophagous insects mediated by plants under drought stress. Based on the findings from an extensive literature review, we found that: 1) The interaction between aboveground and underground phytophagous insects in recent climate is mainly based on the “plant stress hypothesis” and “defense induction hypothesis” and the interaction between aboveground and underground phytophagous insects is affected by the order of phytophagous insects arriving at the host plant, performance parameters of phytophagous insects, life history of plants, and types of phytophagous insects. 2) The effect of drought stress on plants is based on the hypothesis of “growth differentiation” which has been corroborated to some extent. 3) Drought stress can cause changes in plant physiology, thereby affecting the relationship between plants and aboveground leaf-eating insects (chewing insects, stinging insects). 4) Few studies have examined the interaction between plants and underground root-eating insects under drought stress. At present, few studies suggest that the damage to plant roots caused by drought and underground root-eating insects may be superimposed. 5) The interaction between aboveground and underground phytophagous insects mediated by plants under drought stress may be affected by phytophagous insect species; plant species; type, concentration, and distribution of plant defense compounds; plant hormones; plant palatability; plant communities; and habitats. 6) In the future, research on plant-mediated aboveground and underground phytophagous insect interactions under drought stress needs to further reduce experimental limitations, for example, long-term field experiments, expanding the scope of experiments (including more plants and phytophagous insect species), innovative experimental methods, and evaluation of the dominant mechanism between interactions.
Simulation of response of sugarcane growth to meteorological drought scenarios based on Aqua Crop model in Nanning
YANG Yunchuan, CHENG Yuhao, LIANG Liqing, LIAO Liping, WANG Tingyan, ZHANG Huiya, YANG Xingxing, HU Jiaqiu
2022, 30(12): 1900-1912. doi: 10.12357/cjea.20220315
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Rain-fed sugarcane is mainly cultivated in Nanning, an area with extensive hills and karst. The soil water deficit caused by meteorological drought is a major factor affecting sugarcane growth and yield in this region. The cane yield has experienced huge losses due to drought over the years. Therefore, the daily standardized weighted average precipitation index (SWAP) was calculated using 0.1° grid daily meteorological data from 1979−2018, and the meteorological drought characteristics and possible drought event scenarios during the sugarcane growth period were identified. Finally, the Aqua Crop model was employed to simulate and reveal the mechanisms of sugarcane growth, biomass, and yield accumulation in response to meteorological droughts of multiple intensities and durations. The results showed that the duration, intensity, and frequency of meteorological drought presented significant spatial heterogeneity in Nanning, and meteorological drought events mainly occurred during the sugarcane growth stages of sprouting, stem elongation, and maturity. In addition, seasonal droughts with durations longer than 30 days and sudden droughts with durations less than 30 days occured alternately in the study area. The Aqua Crop model showed good simulation accuracy with the yield determination coefficient (R2) reaching 0.92, and the root mean square error as 3.84%, which were achieved after the sensitivity analysis by the Extended Fourier Amplitude Test (EFAST) and the crop parameter localization for the model. That is, the Aqua Crop model had good simulation accuracy and practical value in this study. The simulation results of a typical meteorological drought year demonstrated that the cane yield (Y) and biomass accumulation (B) were sensitive to meteorological drought of all intensities. However, transpiration (Tr) was sensitive to meteorological drought only during the tilling and stem elongation stages, and canopy coverage (CC) appears to have a significant lag effect in response to meteorological drought. The variation in the above four factors showed an obvious response when the meteorological drought lasted for 15 days or more during the sprouting stage. Nevertheless, the variation in the above four factors appeared to be a significant response when the meteorological drought lasted for only 5 days or more during the stem elongation stage. There was no significant response of the above four factors to meteorological drought for all intensities and durations in the maturity stage. In terms of different meteorological drought intensity scenarios, the reduction rate variations of cane yield (Yw), biomass (Bw) and transpiration (Trw) were, respectively, 0−24.0%, 0−18.5%, and 0−15.9% when the duration of light drought increased from 5 to 35 days; 25.0%−37.0%, 20.0%−29.3%, and 8.0%−24.4% when the duration of moderate drought increased from 15 to 45 days; and 33.5%−40.0%, 26.2%−31.7%, and 18.9%−25.7% when the duration of severe drought increased from 35 to 50 days. These results reveal the quantitative mapping relationship between sugarcane growth process, cane yield accumulation, and meteorological drought for all intensities and durations in the study area, which plays an important scientific supporting role in the chain transmission mechanism analysis of sugarcane drought among meteorological drought, soil moisture, and sugarcane growth, in multi-stage drought early warning systems, and in the intelligent management of drought dynamic risk.
Crop Cultivation and Physiological Ecology
Effects of phosphorus application and rhizobial inoculation on nitrogen and phosphorus uptake in soybean||maize intercropping systems in different soil types
WANG Qianqian, LIU Zhiqiang, CHEN Kang, WANG Xiurong
2022, 30(12): 1913-1924. doi: 10.12357/cjea.20220124
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A pot experiment was conducted to compare the effects of rhizobial inoculation on growth, nitrogen (N) and phosphorus (P) uptake, and rhizosphere chemical properties of soybean [Glycine max (L.) Merr.] and maize (Zea mays L.) intercropping systems with different P fertilizer applications in both acidic and calcareous soils, to provide a reference for the field application of rhizobial inoculants. The pot experiment with ‘BX10’ soybean variety and ‘Zhengtian 68’ maize variety as experimental materials adopted a three-factor experimental design, including factor A, P levels [with P fertilizer (+P) and without P fertilizer (–P)]; factor B, two soil pH types (acid soils form Ningxi and Wengyuan, and calcareous soils form Sanping and Changping); and factor C, two inoculation treatments [with rhizobial inoculation (+Ri) or without rhizobial inoculation (–Ri)]. The nodule traits of soybean, plant dry weight, total N and P uptake, and related rhizosphere traits of soybean and maize were determined at the pod stage of soybean. The results showed that inoculation with rhizobia increased the total N uptake of the intercropped soybean under P application in acidic soil, and inoculation with rhizobia improved nodule traits and increased total N uptake of the intercropped soybean regardless of P application and promoted total P uptake of the intercropped soybean in calcareous soil. In both calcareous soils, the total P uptake of the inoculated soybean plants increased significantly. In the calcareous soil of Sanping, the rhizosphere pH was significantly reduced and the rhizosphere acid phosphatase activity of the inoculated soybean significantly increased after rhizobial inoculation and P application. In the calcareous soil of Changping, the rhizosphere alkaline phosphatase activities of intercropped soybean and maize significantly increased after inoculation with rhizobia under P application. With increased total N and P uptake, rhizobial inoculation increased the plant dry weight of intercropped soybean in calcareous soil but had no effect on plant dry weight and total N and P uptake of intercropped maize. In conclusion, soil pH and P availability significantly influenced the effectiveness of rhizobial inoculation. In acidic soil, inoculation with rhizobia increased the total N uptake of intercropped soybean under P application. In calcareous soil, inoculation with rhizobia could promote the synergistic effects of N and P and further promote the growth of intercropped soybean. The promotion of P mobilization and acquisition by rhizobial inoculation might be attributed to the enhancement of rhizosphere processes in calcareous soil.
Leaf senescence characteristics post-anthesis at different positions of spring maize canopy under different cultivation models
WANG Dan, LYU Yanjie, YAO Fanyun, XU Wenhua, CHEN Shuaimin, SHAO Xiwen, CAO Yujun, WANG Yongjun
2022, 30(12): 1925-1937. doi: 10.12357/cjea.20220291
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Post-silking is a critical period for maize yields. This study aimed to elucidate the senescence characteristics of spring maize leaves at different parts of the canopy under different cultivation modes, to understand the mechanism of yield formation and provide a theoretical basis for the regulation of senescence of maize plants in different cultivation models. Four cultivation modes with different agronomic measures were set up by integrating planting density, tillage method, and fertilizer management; they included inherent soil production (ISP), farmer household model (FP), high-yield and high-efficiency model (HH), and super-high-yield model (SH). The leaf area dynamic change model y=aeb−cx/(1+eb−cx) was used to analyze the senescence process of leaves, and photosynthetic pigment and antioxidant enzymes activities were measured in different parts of the leaves to compare the senescence characteristics of maize leaves under different cultivation modes. The yields of HH (12 445.55 kg∙hm−2) and SH (13 759.07 kg∙hm−2) were significantly higher than that of FP and ISP; they increased by 14.4% and 26.4%, respectively (P<0.05), compared with that of FP. The dry matter weight of SH increased by 18.5% and 10.4% compared with that of HH at silking and maturity stages (P<0.05), respectively, and that of HH increased by 2.8% (P>0.05) and 17.7% (P<0.05) compared with that of FP, respectively. Compared with FP, HH and SH started senescence later and the upper leaves were the most typical, with an average decrease in senescence rate of 26.7% and 18.0%, respectively (P<0.05). Compared with FP, the times to maximum reduction rate of relative green leaf area of HH and SH increased by 12 d and 8 d, and the maximum leaf area per plant increased by 8.7% and 6.6%, respectively (P<0.05). From 0 to 60 d after silking, the average leaf areas of lower canopy of HH and SH were 42.4% and 17.3% higher than that of FP, respectively (P<0.05). The photosynthetic pigment contents and protective enzymes activities of the lower and middle leaves of HH and SH plants were significantly higher than those of FP plants after silking. The activities of protective enzymes in the HH middle and lower leaves remained at a high level and decreased slowly during late growth period. After silking, the MDA content of all parts of the maize leaves in different cultivation modes tended to increase, and the MDA content of HH and SH remained at a lower level than that of FP. Compared with FP, for HH and SH with the integration of dense planting, deep tillage, and split fertilizer application technology, the leaf senescence started later in the upper part of the canopy during the flowering period, but the leaf area in the middle and lower parts showed higher and slower senescence. In addition, after silking, the pigment content was very high and decreased slowly, and the leaf protective enzyme activity was very high; this significantly slowed down the senescence process of middle and lower leaves and was conducive to photosynthesis assimilation and high yield.
Effects of all straw return on root secretions of wheat in different seasons
WU Yu, CAI Hongmei, XU Bo, YU Min, WANG Pengna, DAI Wenci, ZHANG Mengxiang, REN Yi, WU Wenming, LI Jincai, CHEN Xiang
2022, 30(12): 1938-1948. doi: 10.12357/cjea.20220199
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Root exudates play an important role in the exchange of substances and chemicals between plants and soil. Different straw returning modes change the growth environment of wheat roots, and wheat root exudates have different response characteristics to different straw returning modes. Screening for a suitable straw returning mode is a key issue for sustainable and high-quality development of wheat production. Metabolomics of root exudates can potentially help us to better understand the chemical interaction between roots, soils, and organisms in the rhizosphere. In this study, to investigate the effects of all straw return in different seasons of winter wheat-summer maize rotation system on wheat root exudates in the lime concretion black soil area in Huaibei Plain, four straw returning modes were developed, they included all wheat straw smashed mulching in summer maize season (T1), all wheat straw smashed mulching in summer maize season + all maize straw crushed burying in winter wheat season (T2), all maize straw crushed burying in winter wheat season (T3) and no straw returned to field (CK). The metabolomics of wheat root exudates collected under different straw returning modes was investigated based on non-targeted metabolomics combined with liquid chromatography-mass spectrometry. Multivariate statistical analysis methods were used to quantify the differences in metabolomics among different straw returning modes. The results showed that T1 treatment increased the root length and root dry weight of wheat during the overwintering period and resulted in higher root vigor compared to other treatments. T1, T2, and T3 detected 330, 110, and 89 differential metabolites compared with CK, respectively. Compared with CK, the relative contents of some oligosaccharides, such as stachyose and verbascose, in the root exudates of T1 increased, and the galactose metabolism and glycolytic pathways were greatly affected. The relative contents of proline, valine, isoleucine, glutamic acid, and glutamine of T1 increased, and the metabolism of arginine and proline, and D-glutamine and D-glutamate metabolism were affected greatly. The relative contents of 3-hydroxysebanoic acid, creatine phosphate, 3-isopropenylglutaric acid, 4-heptanoic acid, and cinnamic acid of T1 increased. The results indicated that all wheat straw smashed mulching changed the characteristics of wheat root exudates; increased the root length and dry weight of wheat by increasing the relative content of some sugars, amino acids, and organic acids; and maintained high root vitality under the condition of straw return. Metabolomic analysis of root exudates based on non-targeted metabolomics combined with liquid chromatography-mass spectrometry could provide an important theoretical basis for the study of the efficient utilization of straw resources and high yield, high quality, and high-efficiency development of wheat production in the lime concretion black soil area in Huaibei Plain.
Selection of high-temperature-resistant cotton cultivars based on physiological indexes and analysis of their relationship with root phenotypes
SI Peng, LIU Liantao, SUN Hongchun, ZHANG Ke, BAI Zhiying, LI Cundong, ZHANG Yongjiang
2022, 30(12): 1949-1958. doi: 10.12357/cjea.20220114
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In recent years, high temperatures have become an important abiotic stress factor that limits the growth and development of cotton in the Yellow River basin. The characteristics of different cotton cultivars in response to high temperatures, especially differences in root phenotypes, remain unclear. In this study, 15 cotton cultivars commonly cultivated in the Yellow River basin were cultured to the six-leaf stage in an artificial climate chamber under normal conditions (25 ℃ day/25 ℃ night), followed by treatments with control (25 ℃ day/25 ℃ night) and high (35 ℃ day/30 ℃ night) temperatures. Seven days later, 10 physiological indicators, including gas exchange parameters, chlorophyll fluorescence parameters, antioxidant system enzymes, and root phenotypic parameters, such as root length, root surface area, root volume, and average root diameter, were measured. The results showed that, compared with the control, for all cultivars, values of net photosynthetic rate, stomatal conductance, transpiration rate, PSⅡ maximum photochemical efficiency (Fv/Fm), and relative chlorophyll content (SPAD) generally decreased after high-temperature treatment; while activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), soluble sugar content, and relative conductivity increased. Ten indicators were integrated into two comprehensive indicators, and the high-temperature resistance coefficient and cultivar score for each cultivar were obtained using principal component analysis. Three high-temperature-resistant cultivars, ‘Shuofeng 1’ ‘Guoxin 9’ and ‘Lumianyan 28’; and five high-temperature-sensitive cultivars, ‘Shikang 126’ ‘Hanwu 216’ ‘Guoxin 4’ ‘Cangmian 268’ and ‘Nongda 601’, were screened out via cluster analysis. The correlation between the ratio of high temperature to control of root phenotypic indicators and the high-temperature tolerance score of high-temperature-resistant cultivars was further analyzed. The correlation coefficients of root length, root surface area, root volume, and mean root diameter were 0.766 (P<0.01), 0.659 (P<0.01), 0.628 (P<0.05), and 0.501 (P>0.05), respectively, indicating that root phenotypic parameters decreased less after high-temperature stress. Root length, surface area, and volume can also be used as indicators to screen cultivars resistant to high temperatures. This study provides theoretical and practical support for the selection and regulation of high-temperature-resistant cultivars.
Resource use efficiencies and economic benefits of winter wheat-summer maize cropping system with double mechanical grain harvest
ZHOU Baoyuan, CHEN Chuanyong, SUN Xuefang, GE Junzhu, DING Zaisong, MA Wei, WANG Xinbing, ZHAO Ming
2022, 30(12): 1959-1972. doi: 10.12357/cjea.20220279
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The evaluation of the mechanical grain harvest of winter wheat-summer maize cropping system and water-saving planting pattern of winter wheat without reduction in annual grain yield is an important way to improve the economic and ecological benefits of winter wheat-summer maize double cropping system in the Huang-Huai-Hai Plain. In this study, field experiments with the traditional winter wheat-summer maize cropping system (CK) and mechanically grain-harvested winter wheat-summer maize cropping systems (TR) were conducted at Jiaozhou of Shandong Province, Daming of Hebei Province, and Xinxiang of Henan Province from 2018 to 2020 to determine their annual yield, climate resource allocation and utilization, and economic benefits. The results showed that annual climate resources were redistributed through extremely late sowing (Mid November) of winter wheat and extremely late harvesting (Early November) of summer maize for TR, which affects the grain yield of wheat and maize. Compared with CK, TR decreased the grain yield of winter wheat by 9.2% across years and experimental sites owing to the reduction in biomass, spike number, and 1000-kernel weight. However, the yield of mid-late-maturing summer maize varieties in TR increased by 8.1% across years and experimental sites compared with that in CK, and the increase in kernel weight contributed to the yield increase in maize in TR. Moreover, there was no significant difference in the total biomass of summer maize between CK and TR, but the harvest index of summer maize in TR was higher than that in CK. Therefore, no significant difference in annual grain yield was found between TR and CK. The grain water content of summer maize at harvest for TR was between 14.1% and 16.8% and was significantly lower than that for CK. In addition, compared with CK, TR reduced water consumption during the winter wheat season and annual by 15.3% and 6.0% across years and experimental sites, respectively; but increased their WUE by 15.2% and 8.4%, respectively. Although the output and economic benefits of winter wheat under TR treatment reduced, the output and economic benefits of summer maize increased by 8.7% and 16.2% across years and experimental sites, respectively. As a result, the annual economic benefit of TR increased by 5.6% across years and experimental sites compared to that of CK. The results indicated that the establishment of doubl mechanical grain harvest of combined the extremely late sowing of winter wheat and extremely late harvesting of summer maize with mid-late maturity could help to achieve water-saving for winter wheat and mechanical grain harvesting of summer maize, ensuring a higher annual grain yield and economic benefit. This study provides ideas for improving the mechanization of winter wheat-summer maize double cropping system and the sustainable use of water resources.
Agricultural Resources and Environment
Research progress in soil health regulation technology for protected agriculture
GENG Wencong, MA Yue, ZHANG Yuxue, ZHU Feng
2022, 30(12): 1973-1984. doi: 10.12357/cjea.20220349
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Soil health has become a limiting factor in the development of modern protected agriculture. Understanding the importance and underlying regulatory mechanisms of soil health and designing approaches towards healthy soil management are important guidelines for improving soil productivity and sustainable development in facility agriculture. In this article, the connotations of soil health in protected agriculture and its evaluation indicators are summarized. Furthermore, this paper reports existing problems, such as a high replanting index, continuous crop obstacle, and soil-borne diseases that may restrict healthy soil management. Next, we discuss techniques that are based on crop and soil regulation to improve soil health, including optimizing planting structures, cultivating resistant varieties, regulating nutrients, building artificial microbial communities, and regulating soil food webs. Finally, this article suggests that a soil health evaluation system for facility agriculture should be constructed, and new regulatory techniques should be introduced to provide a reference for more in-depth research on soil health improvement for protected agriculture.
Funding, implementation and outcomes research projects in farmland chemical and biological pollution of the National Key Research and Development Program of China in the 13th Five-Year Plan period
XU Changchun, LIU Jie, XIONG Wei
2022, 30(12): 1985-1992. doi: 10.12357/cjea.20220823
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Chemical and biological pollution in farmland is a new area for agricultural ecology and environmental research both in China and abroad. Based on project management work, the authors summarized application submission, peer review, and grant funding processes; analyzed research outcomes; and briefly introduced major research results concerning the two research projects in the chemically and biologically polluted farmland funded by the National Key Research and Development Program of China in the 13th Five-Year Plan period. Through funding and implementation of the projects, a number of achievements have been made in basic research, technical development, and application. With this paper, we aim to provide references for related academics and policy makers and boost future research in the area of farmland chemical and biological pollution.
Factors influencing electricity-to-water conversion metering method for irrigation water consumption in Hebei Plain
LI Fei, TAO Peng, QI Yongqing, LI Hongjun, WANG Hongxi, WANG Ning, PEI Hongwei, ZHANG Xiying
2022, 30(12): 1993-2001. doi: 10.12357/cjea.20220288
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Regional grain production in the Hebei Plain relies on groundwater irrigation to maintain high and stable yields. However, numerous irrigating wells are scattered, making it difficult to obtain reliable groundwater abstraction for agricultural irrigation. The electricity-to-water conversion method is an indirect measurement of groundwater pumping. The use of electric energy consumption as a proxy offers a solution to the problems of maintenance and acceptance, as electricity is usually metered for fee collection and metering is well accepted. Moreover, it can be efficient and convenient in measuring groundwater abstraction for agricultural irrigation. Based on the electricity-to-water conversion factors of county-level agricultural irrigation and the monitoring results of groundwater depth, this study analyzed the regional characteristics of the electricity-to-water conversion factor and the correlation between groundwater depth and the conversion factor in the Hebei Plain. The Luancheng Agro-Ecosystem Experimental Station of the Chinese Academy of Sciences, as a typical site, was selected for the irrigation experiment to study the relationship between electricity consumption and groundwater abstraction and analyze the influence of time consumption, irrigation method, and seasonal variation of the electricity-to-water conversion factor. We found that: 1) Under the same depth of groundwater level, the electricity-to-water conversion factors in the piedmont region were higher than those in the mid-eastern region of the Hebei Plain, and with a declining water table, the electricity-to-water conversion factor decreased. For every 10 m decrease in the water table, the electricity-to-water conversion factor of the deep aquifer in the piedmont and mid-eastern regions decreased by 0.42 m3∙kWh−1 and 0.15 m3∙kWh−1, respectively. 2) The results of the irrigation experiment showed that the relationship between electricity consumption and groundwater abstraction was relatively stable, and the fluctuation range of the electricity-to-water conversion factor between different times consuming for one irrigation was 5.7%. The irrigation season from early March to mid-June was affected by the seasonal variation of the groundwater level, and the seasonal variation of the electricity-to-water conversion factor was approximately ±10%. Different irrigation methods, such as pipe irrigation and sprinkler irrigation, had a significant impact on the actual conversion factor, and the efficiency of pipe irrigation was 28.8% higher than that of sprinkler irrigation. 3) The current county-level results for the electricity-to-water conversion factor in the Hebei Plain cannot support the requirements of farmers for irrigation metering, water rights, and water resource tax verification. Seasonal variations in groundwater level, irrigation methods, and non-irrigation electricity consumption should be considered to improve the metering accuracy of groundwater abstraction using electricity as a proxy.
Transcriptome analysis of copper resistance in Lysobacter soli strian RCu6
LI Fuyu, CHEN Shuaimin, LIU Mengshuai, CHEN Miaomiao, LI Xiaofang, LIU Binbin
2022, 30(12): 2002-2010. doi: 10.12357/cjea.20220198
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Copper is a trace element that has essential functions in many cellular enzymes; however, excessive copper levels can be toxic. Bacteria have evolved several copper resistance strategies, but the underlying mechanisms are not yet fully understood. Elucidating the mechanisms of copper resistance in bacteria is important for developing microbe-based techniques for mitigation of heavy metal pollution. In this study, a highly copper-resistant (resistant to copper concentrations up to 3.2 mmol∙L−1) bacterial strain RCu6 was isolated. The genomic characteristics of RCu6 were studied using whole-genome sequencing, and copper resistance mechanisms were analyzed using transcriptome analysis. Whole-genome sequencing of strain RCu6 indicated that it belonged to Lysobacter soli. Compared to other strains in the same genus, this strain has a unique DNA fragment encompassing cop, cus, czc, and other homologous copper resistance genes. Transcriptome analysis showed that 315 (239 up-regulated and 76 down-regulated) and 839 (449 up-regulated and 390 down-regulated) genes were differentially expressed under 0.8 mmol∙L−1 and 1.6 mmol∙L−1 copper concentrations, respectively. The differential gene expression was mainly associated with copper homeostasis, histidine metabolism, sulfur metabolism, and iron-sulfur cluster assembly metabolism, indicating that these processes may play important roles in copper resistance of RCu6. The results of the transcriptome analysis were further verified using qPCR. The expression levels of 12 randomly selected genes associated with copper resistance showed significant correlations between qPCR and RNA-Seq data (R2=0.84 for GAPDH gene and R2=0.98 for 16S rRNA gene as internal reference genes). Therefore, the genomic and transcriptome results suggest that copper resistance in the strain Lysobacter soli RCu6 is an intracellular multi-system collaborative process. This study provides new information for understanding the complex regulatory network of copper homeostasis in prokaryotes. It also provides bacterial resources and a theoretical basis for the remediation of heavy metals in farmland soil.
Agricultural Ecology Economics and Ecoagriculture
Characteristic evolution and influencing factors of the spatial correlation network of agricultural green total factor productivity in China
TAN Rihui, LIU Huimin
2022, 30(12): 2011-2022. doi: 10.12357/cjea.20220339
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Improving agricultural green total factor productivity (AGTFP) is essential to the development of green agriculture. Few researches has evaluated the characteristics and influencing factors of the spatial correlation network of AGTFP, which is not conducive to the development of green agriculture. Therefore, based on relational data and networks, using data from 31 provinces (cities and autonomous regions) in China from 2010 to 2019, this study used the SBM-Undesirable model to determine AGTFP, and adopted the social network analysis method to analyze the overall structure and individual characteristics of the spatial correlation network of AGTFP. The dynamic process of factors affecting the spatial correlation network of AGTFP was analyzed through a quadratic assignment procedure (QAP) model. The results revealed that: First, the AGTFP in China showed an upward trend as a whole, and the average value increased from 0.47 in 2010 to 0.85 in 2019 with scope for improvement and high regional variability. In addition, the spatial correlation effect of AGTFP of provinces (cities and autonomous regions) exceeded geographical proximity, forming a complex spatial correlation network throughout the country. Second, the correlation and stability of the spatial correlation network of AGTFP were reinforced during the study period. From 2010 to 2019, the number of network relationships increased from 124 to 215, and the network density increased from 0.13 to 0.23. Meanwhile, the network level reduced from 0.53 to 0.29, and the network efficiency reduced from 0.84 to 0.67. Third, the centrality of the spatial correlation network of AGTFP in China fluctuated in different years. The eastern region, relying on a more developed economy, had become the main factor gathering place in the spatial correlation network; therefore, it had a high central degrees. While parts of the western region had a very high central degree due to the inflow of factors from the central and eastern regions mainly through policy support. A few areas in the central region haf a very high central degree due to their superior location. Finally, the results of this study demonstrated that the effects of influencing factors on the spatial correlation networks of AGTFP in China varied from year to year, and the level of economic development, agricultural development, informatization, transportation improvement, and spatial adjacency had a marked impact on the formation of the spatial correlation networks of AGTFP in China. Therefore, the characteristics and influencing factors of AGTFP should be considered, and effective measures should be taken to enhance the spatial correlation of AGTFP.
Government promotion, social networks and farmers’ adoption behavior of ecological farming technology
WEI Binbin, YANG Zhihai
2022, 30(12): 2036-2049. doi: 10.12357/cjea.20220305
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The application of ecological farming technology is significant to ensure national food and ecological security, but the adoption rate at farmer level is still low. To explore the role of government promotion and social networks in improving the application of ecological farming technology, this study used Ordered Probit and Tobit models and a sample of 787 farmers from six major grain-producing provinces to empirically investigate the impacts of government promotion and social networks on farmers’ behavior of using ecological farming technology. This study contributes to the literature on the adoption of agricultural technology in two ways. First, we evaluated and compared the effects of government promotion and social networks on the adoption of ecological farming technology. Particularly, we investigated the moderating effects of heterogeneous social networks on government promotion, which is helpful in utilizing different channels of technology extension. Second, considering farmers’ use of ecological farming technology has changed from self-providing to outsourcing, we estimated the impacts of government promotion and social networks on farmers’ preferences for the outsourcing adoption of ecological farming technology. The main findings were as follows: First, although the direct impact of government promotion on farmers’ adoption of ecological farming technology was not significant, government promotion had a significant and positive impact on farmers’ adoption of ecological farming technology under the moderating effect of kinship networks. Second, government promotion had a significant and negative impact on farmers’ adoption of ecological farming technology, that is, it was not conducive for farmers to adopt ecological farming technology through outsourcing. However, relationship networks, especially kinship network, significantly weakened the negative effect of government promotion. Third, social networks played an important role in promoting farmers’ adoption of ecological farming technology. Whether it was the kinship or general network, it had a positive impact on farmers’ adoption of ecological farming technology, encouraging farmers to adopt the outsourcing of relevant technologies. However, the influence of the kinship network was greater than that of the general network. Based on the above findings, this study suggests that it is important to consider the heterogeneous and complementary effects of different social networks when promoting the adoption of ecological farming technology at the farmer level. In addition, it is helpful to use socialized services in agricultural production to promote ecological farming technology.
Agricultural Ecologic Economics and Ecoagriculture
Ecological development of agricultural engineering with the background of rural revitalization: ecological agricultural engineering
WEI Xiuju, LIAO Yan, ZHU Ming
2022, 30(12): 2023-2035. doi: 10.12357/cjea.20220400
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Abstract:
Rural revitalization is a strategic goal of the overall, comprehensive, integrated, and coordinated development of agricultural and rural areas in the new era. In the context of rural revitalization, China’s agricultural engineering needs to further innovate and expand to meet the needs of agricultural and rural area development in the new stage. Ecological agricultural engineering is a cross-discipline of agricultural engineering and agricultural ecological engineering. Focusing on ecological agricultural engineering, this research analyzed its concept and connotation and discussed the importance, future development prospects, development direction, and existing problems under the background of rural revitalization. Ecological agricultural engineering is the ecological development of agricultural engineering, which comprehensively promotes the ecological thought of traditional agricultural engineering in terms of development ideas and connotations, and expands the ecological field of agricultural engineering. Given the great demand for rural revitalization, development of ecological agricultural engineering has been proposed. Ecological agricultural engineering is a technical means to realize ecological agriculture, which can meet the developmental needs of rural revitalization, ensure the sustainable productivity of agricultural ecosystems, and promote the sustainable development of agriculture and rural areas. Ecological agricultural engineering can be regarded as a cross-discipline of ecological engineering and agricultural engineering. The importance of developing ecological agricultural engineering is mainly reflected as follows: promoting the construction of ecological civilization; supporting the high-quality development of rural industry, systematic and all-round rural revitalization; and promoting the sustainable development of agricultural and rural areas. In the future, Ecological agricultural engineering can provide an important guarantee for food security, and it is an important measure to alleviate the energy crisis, an effective path to the construction of beautiful villages, and a way to achieve prosperity. This can enrich and expand the discipline connotation of agricultural engineering to meet the needs of the new situation of rural revitalization, so it has broad developmental prospects. The development of ecological agricultural engineering will play a major role in promoting rural revitalization in China in the field of ecological development of agricultural engineering.

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