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Screening of accumulating plants in farmland surrounding typical lead and zinc smelting enterprises
HE Mengke, GUO Junmei, YANG Junxing, ZHENG Guodi, CHEN Tongbin, MENG Xiaofei, LI Yufeng, LIU Jie
 doi: 10.12357/cjea.20220711
Abstract(53) HTML(14) PDF(3)
As one of the most important lead (Pb) and zinc (Zn) smelting production bases in China, the heavy metal content in the farmland surrounding the enterprises in Jiyuan City of Henan Province seriously exceeded the national standard due to the backward technology and large pollutant discharge. In order to explore the characteristics of heavy metal contamination in farmland around Pb and Zn smelting enterprises in Jiyuan City, select the dominant plants for remediation and safe utilization of heavy metal-contaminated farmland, and establish a preliminary remediation model, field experiments were conducted on farmland surrounding Pb and Zn smelting enterprises in Jiyuan City. The study included investigating the characteristics of cadmium (Cd), Pb, and arsenic (As) pollution in soil, analyzing the heavy metal content in main agricultural products, selecting 17 kinds of heavy metal-accumulating plants for field cultivation, and studying their biomass, heavy metal contents, bioconcentration factor, extraction amount, and remediation efficiency. The results showed that the average content of Cd, Pb, and As in soil was 2.22 mg·kg−1, 173.1 mg·kg−1 and 18.38 mg∙kg−1, respectively, which were mainly distributed in the cultivated layer. Among them, the content of Cd and Pb exceeded the risk screening values in the Environmental Quality Standard for Soils (GB 15618—2018), and the single factor pollution index reached 3.71 and 1.02, respectively. In terms of the wheat and maize cultivated on the contaminated farmland, the content of Cd, Pb, and As in maize seeds did not exceed the values in the National Food Safety Standards (GB 2762—2022), but the Cd and Pb content in wheat seeds exceeded the standards, while the exceeding rates both reached 100%. In plant cultivation experiments, the biomass and heavy metal enrichment capacities of the 17 kinds of accumulating plants differed significantly. The biomass of Amaranthus hypochondriacus was the highest, reaching 29 598 kg·hm−2, which was 46.61 times that of Noccaea caerulescens (635 kg·hm−2). The contents of Cd, Pb, and As in the 17 plant species were 2.90−30.90 mg·kg−1, 7.81−93.1 mg·kg−1, and 3.76−22.9 mg·kg−1, respectively. The bioconcentration factors of Cd, Pb, and As were 1.31 to 13.92, 0.05 to 0.54, and 0.20 to 1.24, respectively. Helianthus annuus ‘S606’ had the largest Cd, Pb, and As comprehensive bio-concentration index of 2.3. Combining plant biomass and enrichment capacity, 17 plant species showed clear differences in the removal efficiency of contaminated soil. Cluster analysis showed that Amaranthus hypochondriacus, Brassica napus ‘Zhongyou 1000’, and Helianthus annuus ‘S606’ had higher Cd and Pb accumulation and remediation capacities in soil. The removal efficiency of these three species was higher than 1.90% for Cd and 0.07% for Pb, showing a promising potential for remediation of Cd and Pb-contaminated soils. In addition, Brassica napus and Helianthus annuus can be further processed to produce edible oil, feed, or fertilizer, which can bring economic benefits while remediating soil. In conclusion, the farmland surrounding the Pb and Zn smelting enterprise in Jiyuan City was typically light to moderately contaminated with Cd and Pb. In response to this situation, two technical modes of heavy metals-contaminated farmland remediation were proposed: Amaranthus hypochondriacus-Brassica napus rotation remediation mode and Helianthus annuus monoculture remediation mode. Both modes can achieve high remediation efficiency and were viable and extendable.
Impact of aquatic product trade on land use, carbon emissions and biodiversity
LI Zhuangzhuang, LIU Ling, MA Lin, BAI Zhaohai
 doi: 10.12357/cjea.20230009
Abstract(79) HTML(40) PDF(16)
Currently, the aquatic product trade plays an increasingly important role in global resources and the environment because 37% of global aquatic products are traded rather than consumed locally. Previous studies have mainly analyzed the resource and environmental costs caused by the substitution of aquatic products for livestock products. However, little is known about the impacts of aquatic product trade on the ‘resource-environment-biodiversity’ system. Here, a review was conducted using a combined method of environmental footprint and life-cycle assessment. This review focuses on (1) the changes in trade volume, trade species, and trade countries, and (2) the impact of the aquatic product trade on land use, greenhouse gas emissions (GHG), and biodiversity. The results showed that the export volume of aquatic products in 2020 increased five-fold compared with that in 1976, and the growth rate of trade followed a profile termed ‘fast and then stable.’ The aquatic product trade has expanded from southern Europe to the rest of the world. The major trade species are capture products (including sardines, cod, and tuna). However, the share of aquaculture products in total aquatic trade products has increased linearly since 1976: from 5% in 1976 to 25% in 2020. The increase in the aquaculture product trade affects global land-use change, virtual GHG emissions, and biodiversity in aquatic and terrestrial systems. Therefore, to achieve the sustainability of global aquatic products in the future, it is necessary to share advanced production technologies, optimize trade structures, and adjust trade species globally. More specifically, producers should optimize aquaculture structure, technology, and the industrial chain, and consumers should reduce the consumption and trade of aquatic products with high resource and environmental costs.
Effects of content dynamics of NO3-N and phenolic acids in soil on root growth of cotton seedlings under the return of wheat straw
LI Jianan, YANG Changqin, SHU Hongmei, ZHANG Guowei, WANG Xiaojing, LIU Ruixian, CHEN Jiamin, WANG Feibing, CHEN Xinhong
 doi: 10.12357/cjea.20220918
Abstract(56) HTML(29) PDF(7)
Nitrate nitrogen (NO3-N) is the main form of nitrogen released from crop straws under dry farming conditions, and is the main form of nitrogen absorption by the roots and the plant root growth regulatory signal of cotton. Straw return affects the availability of soil and fertilizer N, thus inhibiting the early growth of crops and even decreasing crop yields. The straw return also releases many phenolic acids, inhibiting crop seed germination and root growth. This study aimed to reveal the mechanisms by which the contents dynamics of NO3-N and phenolic acid in the soil affect the growth of cotton seedlings under the return of wheat straw. Based on the 11-year return of wheat straw, field experiments were conducted in 2021 and 2022 at Jiangsu Academy of Agricultural Sciences Experimental Dtation in Nanjing, Jiangsu Province, China. Two treatments, wheat straw removal (CK) and wheat straw return (S), were applied. The contents of NO3-N and phenolic acid in the soil of the subsequent cotton field, the NO3-N content and nitrate reductase activity of cotton seedlings, the activity and morphology indices of cotton roots, and the biomass of cotton seedlings were investigated. The results demonstrated that straw return increased the contents of NO3-N and phenolic acid in the soil, and the effect on the 0–20 cm soil layer was greater than that on the 20–40 cm soil layer. With a delay of days after the straw return, the contents of NO3-N and phenolic acid in the soil increased and then decreased, reaching a peak at 24−31 d after the straw return. Within 31 days of straw return, the root activity, root NO3-N content, nitrate reductase (NR) activity, root biomass, and morphological indices of cotton seedlings under the straw return treatment were significantly lower than those under the CK treatment but showed the opposite trend after 31 d of straw return. The correlation analysis showed that phenolic acid content in 0–20 cm soil were significantly and negatively correlated with the root activity, NO3-N content, length, diameter, and surface area of the root, and the aboveground biomass of cotton seedlings. The NO3-N content in different soil layers was positively correlated with the index of morphology and physiology and the biomass of cotton seedlings but did not reach a significant level. The effect of straw return on the growth of cotton seedlings showed a trend of “first inhibition and then promotion.” Within 31 d after straw return, the “inhibition effect” of phenolic acid in soil on the growth of cotton seedlings was greater than that of the “fertilization effect” of straw. Higher phenolic acid content reduced the root activity and root growth of cotton seedlings, inhibiting the absorption and utilization of NO3-N in cotton seedlings. After 31 d of straw return, the “fertilization” effect of straw was greater than the “inhibition” effect of phenolic acid, promoting the root growth of cotton seedlings.
Accuracy evaluation and consistency analysis of multi-source remote sensing land cover data in the Yellow River Basin
WU Zongyang, CAI Zhuoya, GUO Ying, WANG Yanfang
 doi: 10.12357/cjea.20220816
Abstract(117) HTML(54) PDF(17)
With the development of multi-source remote-sensing platforms and technologies, various land cover datasets have been developed that provide a wealth of data to support the understanding of global land cover conditions, land surface process model simulations, and socioeconomic development decisions. However, selecting appropriate data for different regions from nationally or globally available land cover datasets is challenging. In this study, six land cover products in 2020 over the Yellow River Basin, including CLCD_v01_2020, GLOBELAND30, GLC_FCS30_2020, LANDCOVER (30 m), MCD12Q1 (500 m), and CNLUCC1000 (1000 m), with resolutions ranging from 30 to 1000 m, were evaluated for regional-scale accuracy and consistency analysis. Accuracy analyses were performed on six products based on 1540 samples for seven land cover types collected by Google Earth. Data with the highest overall accuracy (OA) were used as a reference for the area consistency analysis of the other five products. Category confusion and confusion mapping analyses were performed on six types of data. Hopefully, this study will provide a scientific reference for users to select appropriate land cover data for the Yellow River Basin. The results showed that the highest classification accuracy was for CLCD_v01_2020, with an OA of 88.12%, followed by GLOBELAND30 (OA=85.32%), GLC_FCS30_2020 (OA=84.09%), LANDCOVER300 (OA=77.79%), MCD12Q1 (OA=73.38%), and CNLUCC1000 (OA=71.82%). The KAPPA coefficients of the land cover products with a resolution of 30 m were all above 0.8, and the classification accuracy decreased as the spatial resolution decreased. CLCD_v01_2020, with the highest OA, was used as the reference dataset, and the area correlations and confusion mapping were calculated separately for the remaining five validation product datasets. The relative proportions of different land cover types were generally consistent across the six products; however, there were still large differences between croplands and grasslands. GLC_FCS30_2020 had the highest correlation with the reference data CLCD_v01_2020, with an R2 value of 0.9976. Category confusion analysis showed that the six data types were generally confused between croplands, forests, and grasslands. There was good consistency in the grasslands of eastern Qinghai in the upper reaches of the Yellow River and the cropland and construction land of the middle and lower reaches. The areas of poor consistency were mainly in the middle reaches of the Yellow River in northern Shaanxi and western Shanxi, which were mainly confused grasslands with forests. For the primary classification of land cover data in the Yellow River Basin, it is recommended that CLCD_v01_2020 data be selected for 30 m resolution and LANDCOVER300 for 100-m scale resolution data. In contrast, secondary classification can be chosen according to the desired classification system.
Effects of long-term cotton straw return and application of manure on soil nutrients and enzyme activity in cotton fields
GUO Zhenwei, LI Yongshan, WANG Hui, CHEN Mengni, FAN Qiaolan, YANG Na, XI Jilong, ZHANG Jiancheng
 doi: 10.12357/cjea.20220614
Abstract(37) HTML(22) PDF(18)
Incorporation of straw and manure into soil plays an important role in nutrient management, maintenance of crop productivity, and improvement of soil quality. An experiment was conducted to clarify the effects of long-term cotton straw returning and manure application on soil nutrient and enzyme activities in continuous cropping cotton fields, and to provide scientific evidence for cotton straw returning and manure application. The experiment relied on a long-term experiment (since 2007) in an agricultural system conducted by the Niujiawa Cotton Agroecosystem Experimental Station of the Cotton Research Institute, Shanxi Academy of Agricultural Sciences. Four treatments were established on the base of application of nitrogen and phosphorus fertilizers, namely straw stubble removal (NP), straw returning (NPS), organic fertilizer application (NPM), and straw returning + organic fertilizer application (NPSM). The cotton yields of the treatments of NPS, NPM, and NPSM significantly increased by 10.23%, 11.10%, and 26.22% (P<0.05), respectively, compared with that of the NP treatment. The contents of soil total nitrogen, total phosphorus, alkali hydrolyzable nitrogen, available potassium, and available phosphorus in the NPSM treatment significantly increased by 48.76%–60.18%, 91.23%–112.18%, 140.63%–229.17%, 35.86%–60.54%, and 146.92%–483.34% (P<0.05), compared with those of the NP treatment, respectively. NPSM treatment significantly increased soil enzymes activities (P<0.05): urease activity by 118.50%–151.84%, phosphatase activity by 76.81%–93.11%, catalase activity by 30.53%–41.33%, and invertase activity by 83.41%–129.32%, compared with those of the NP treatment. There were significant positive correlations between soil nutrient content and soil enzyme activity. Therefore, long-term straw return with manure application can significantly increase cotton yield, nutrient content, and enzyme activity for soil fertility improvement in continuously cropped cotton fields.
Soil AMF community structure and assembly mechanism of Medicago sativa field in Loess Plateau
GAO Rui, LUO Zhuzhu, HE Renyuan, NIU Yining, LIU Jiahe, CAI Liqun, HAI Long
 doi: 10.12357/cjea.20220697
Abstract(148) HTML(60) PDF(14)
Arbuscular mycorrhizal fungi (AMF) mediate the interactions between plants and soils, play crucial roles in terrestrial symbiosis, and are important components of soil microbial communities. However, information on the variations of soil AMF communities with respect to the loess soil properties is limited. Therefore, the present study investigated soil AMF diversity, community structure, and physicochemical properties in Medicago sativa fields and farmland in the Loess Plateau semi-arid area. Soil samples (0–20 cm) were collected in June 2021 from four treatments: maize (Zea mays) field (Farmland) and M. sativa fields established in 2019 (L2019), 2012 (L2012), and 2003 (L2003). Illumina MiSeq high-throughput sequencing and real-time fluorescent quantitative PCR were used to explore the structure and diversity of the AMF communities under the four treatments (Farmland, L2003, L2012, and L2019). Statistical methods (redundancy analysis and molecular ecological network analysis) were used to explore the relationship between soil physicochemical properties and the AMF community. Zero-model analysis was used to reveal the assembly process of the soil AMF community. The results showed that long-term alfalfa planting decreased soil total phosphorus and available phosphorus contents. The AMF gene abundance ranged from 1.02×104 to 1.50×104 copies∙g−1 in dry soil, which was significantly higher in M. sativa field planted in 2003 than in other treatments (P<0.05). Correlation analysis between the abundance of AMF genes and physicochemical factors showed that soil AMF gene abundance was positively correlated with total nitrogen content and negatively correlated with total phosphorus and available phosphorus contents. One class, four orders, seven families, and seven genera of AMF were identified. Glomus, Diversispora, and Paraglomus were the common genera of M. sativa fields and Farmland, and the dominant genera of M. sativa fields and Farmland were Glomus (65.15%−99.12%), mainly contributing to the changes of soil AMF community structure in different treatment groups. Long-term cultivation of M. sativa propagated rare microbial taxa, including Ambispora and Scutellospora, whereas Pacispora and Acaulospora were sterilized. Ambispora was significantly higher in M. sativa field planted in 2019 than in the other treatments (P<0.05). The analysis of the molecular ecological network showed that there were highly abundant genera (Glomus and Paraglomus) that had cooperative relationships in the ecological network, whereas the low-abundance genera (Pacispora and Acaulospora) had competitive relationships in the ecological network. RDA showed no main environmental factors affecting the AMF community structure. The null model was used to infer AMF community assembly processes. In Farmland and M. sativa field established in 2019, community mechanisms were dominantly assembled with deterministic processes (66.67%), with heterogeneous selection contributing the most. For the M. sativa field established in 2012 and 2003, the community mechanisms were dominantly assembled with random processes (100.00%); the undominated processes contributed the most to M. sativa field planted in 2012, and dispersal limitation contributed the most to M. sativa field planted in 2003. The Mantel test showed no main environmental factors driving AMF community assembly. Long-term cultivation of M. sativa increases the number of random processes. This is beneficial for maintaining the sustainability and stability of the artificial grassland ecosystem functions. In summary, long-term M. sativa planting significantly affected the composition of soil AMF communities. This study provides basic data and a theoretical basis for further studies on the microbial mechanisms of AMF on the Loess Plateau after years of M. sativa planting.
Effect of nitrogen fertilizer and soil conditioner on soil carbon and nitrogen content, and oat yield
SUO Wenkang, YANG Jinhan, HU Chenyang, FENG Shasha, TIAN Xiaoming
 doi: 10.12357/cjea.20220553
Abstract(161) HTML(77) PDF(17)
Soil conditioners have been applied in agriculture due to advantages, such as coordinating soil water and fertilizer, improving soil water-retaining and fertility-reserving capacity. A new type of liquid conditioner was introduced in oat cultivation in this study, its’ effects on soil physical properties, and characteristics of soil organic carbon and nitrogen, and oat yield under nitrogen fertilizer reduction were investigated to explore the driving mechanism of N reduction by conditioners on crop yield and soil nutrients. Five treatments were set: no fertilizer (CK), 80% N fertilizer (N80), regular N application (N100), conditioner + 80% N fertilizer (PN80), and conditioner + regular N application (PN100). The results showed that the fertilizer + conditioner treatments differed from the single fertilizer treatments in terms of physical properties, carbon and nitrogen contents, and oat yield. The treatments with conditioner (PN80 and PN100) significantly increased soil water content, field capacity, porosity, and reduced soil bulk density compared with the treatments with only fertilizer. Furthermore, the nitrogen reduction of 20% (N80) significantly increased soil porosity and reduced soil bulk density compared with conventional nitrogen application (N100). The study showed that 20% N reduction had varying degrees of inhibition on organic carbon, total nitrogen, and its components in different soil layers. Furthermore, the addition of the conditioner significantly increased organic carbon, total nitrogen, nitrate nitrogen, active organic carbon, and microbial carbon in the 0–60 cm soil layer and 20−60 cm soil layer compared with the treatments with N fertilizer alone. The effect of the PN100 treatment was the most significant. The effects of different treatments on the nutrients and yield of oats varied greatly, with that of the PN80 treatment being the most significant. Compared with N100, the total N, P, and K contents and crop yield of oats in PN80 significantly increased by 12.93%, 15.16%, 3.69%, and 18.73%, respectively (P<0.05). Compared with N100, N80 significantly reduced N, P, and K uptake in oats at 20% N reduction, but did not cause yield reduction in oats. In conclusion, compared with conventional fertilization, N80 with a soil conditioner improved soil properties, increased soil carbon content, reduced the risk of nitrate N leaching, and significantly increased the nutrient uptake and yield of oat. The effect of 80% N fertilizer + soil conditioner on the nutrient content and yield of oats was the most significant, while the treatment with 100% N fertilizer + soil conditioner was the most effective in improving soil nutrient content. This is essential to realize the green development of agriculture, reduce the environmental impact of fertilizer input, and improve the utilization rate of nitrogen fertilizers.
Evaluation of the effect of future climatic change on Hebei cotton production and water consumption using multiple GCMs
WANG Keyu, YANG Yanmin, YANG Yonghui, LIU Deli, CHEN Li
 doi: 10.12357/cjea.20230016
Abstract(124) HTML(44) PDF(8)
Climatic models are the primary source of uncertainty in climate change impact assessments. Uncertainty can be significantly decreased by using multiple climate models during an assessment. In this study, the crop model APSIM-COTTON was carefully calibrated based on two years of field experiments, and 22 GCM (Global Climate Models) models (AR6) were used to drive crop models to evaluate the effects of climate change on cotton production and water consumption in Hebei Province. The leaf area index, plant height, squares number, bolls number, and dry matter weight of each plant were used to correct various APSIM-COTTON parameters. The coefficient of determination was greater than 0.8, indicating that the simulated and observed values fit well. The trend of climate change at this site was that the solar radiation intensity under SSP1-2.6, SSP2-4.5, and SSP5-8.5 was higher than the baseline (from 1980 to 2010) and increased with time, but it was lower than the baseline under SSP3-7.0. Temperature tended to increase in all scenarios, and the amplitude increased with the increase in radiative forcing and time. In most scenarios, the minimum temperature increased more than the maximum temperature, and annual rainfall increased over time. The responses of cotton production and water consumption to future climate change are the comprehensive effects of CO2 concentration, solar radiation, temperature, rainfall, and other climatic factors. The crop model simulation results showed that the sowing date was advanced under all climate scenarios and future time periods, and all development stages (emergence, squaring, flowering, and harvesting) were shorter than those of the baseline period. In the 2090s, under scenarios SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5, the boll opening stage advanced 9.3, 12.0, 14.7, and 16.0 days, respectively, whereas the harvest stage advanced 15.3, 21.0, 30.3, and 35.2 days, respectively. The annual evapotranspiration (ET) under all scenarios, except SSP3-7.0, showed an increasing trend, whereas the irrigation amount decreased. Under the SSP5-8.5 scenario, the annual ET in the 2030s, 2050s, 2070s, and 2090s increased by 6.5, 7.8, 14.3, and 32.7 mm compared with the baseline, whereas the irrigation amount decreased by 25.7, 23.8, 30.5, and 29.0 mm, respectively. In the future, changes in cotton yield will not be large in scenarios of lower radiation focusing (SSP1-2.6), and there will be a decreasing trend with age under high radiation forcing (SSP5-8.5 and SSP3-7.0). Under SSP1-2.6 and SSP2-4.5 scenarios, lint yield decreased by approximately 61.5 and 46.6 kg∙hm2, respectively, in the 2090s. However, under SSP3-7.0 and SSP5-8.5 scenarios, the reduction by 2090s reached 407.1 and 432.5 kg∙hm2, respectively. In this study, 22 GCM models were used to simulate the response of cotton growth and water consumption to climate change over 100 years in the 21st century, and the changing trends in different scenarios and time periods were compared to provide technical support for developing adaptation strategies to climate change. However, the uncertainty of evaluating the climatic effect on cotton production still exists in this study. More site data should be considered in the calibration process, and more crop simulation models with different mechanisms should be compared in future research.
Impact of joining cooperatives on green production of family farms: an empirical analysis based on 422 provincial demonstration family farms
ZHANG Mingyue, ZHENG Jun, ZHAO Xiaoying
 doi: 10.12357/cjea.20220817
Abstract(45) HTML(19) PDF(9)
Green production is the inevitable course to develop agriculture sustainably. To explore the effective methods of green production, the key area of modern agriculture, for family farms is of considerable theoretical value and practical significance. This study empirically analyzed the influence of family farms joining cooperatives on green production and its mechanism using the ranking selection and explanatory structure models based on the investigation data of 422 provincial demonstration family farms in Shandong Province. 1) Quantitative analysis showed that the proportion of green production of family farms joining cooperatives was evidently higher than that of farms not joining cooperatives. 2) From heterogeneity analysis, the proportion of green production by cooperative leaders’ farms was higher than that of farms with ordinary members. Joining cooperatives was significant for the green production of grain and vegetable family farms but not for fruit and livestock breeding farms. Joining the cooperative had a significant impact on the green production of medium-sized (10–20 people) farms but had no significant impact on the behavior of small-scale (less than 10 persons) and large-scale (more than 20 persons) farms. 3) After the family farm joined the cooperative, the three green production behaviors with the highest adoption rates were applying organic fertilizer (74.35%), water-saving irrigation (68.17%), and subsoiling (65.80%). In contrast, the three green production behaviors with the lowest adoption rates were ecological treatment of livestock and poultry breeding waste (26.84%), recycling pesticide waste (41.81%), and integration of water and fertilizer. 4) The regression equation results showed that family farms significantly increased the possibility of green production by joining cooperatives. Under the control of other variables, joining the cooperative had a significant positive impact on the green production of family farms at the 1% level, with an impact coefficient of 0.554, and the promotion of water-saving irrigation, application of organic fertilizer, and integration of water and fertilizer were more prominent. After considering other control variables, family farm management type, labor force, product quality certification, traceability of origin, and awareness and willingness toward green production all influenced green production. 5) From the explanatory structure model analysis, seven significant influencing factors played independent roles and were also interrelated, forming a complete chain of influencing factors for family farms to participate in green production. Joining the cooperative as a deep-rooted factor directly affected the origin traceability and product quality certification of family farm products and affected the green production of family farms from the source along the positive conduction relationship of “family farm green production cognition → green production willingness →green production behavior.” Therefore, we should encourage and support family farms to join cooperatives, focus on the heterogeneity between farms, and promote green production on farms through the training and supervision of cooperatives.
Analysis of differential metabolites and metabolic pathways of mono- and inter-cropped wheat in response to Blumeria graminis f. sp. tritici infection
CHEN Sheng, WU Xinyu, HE Jianyang, ZHOU Dong, LIU Zhenyang, TANG Li, ZHENG Yi, XIAO Jingxiu
 doi: 10.12357/cjea.20220808
Abstract(93) HTML(59) PDF(9)
Wheat and faba bean intercropping can alleviate the occurrence and severity of wheat powdery mildew. However, the physiological mechanism of intercropping improving wheat disease resistance remains unclear. This study aimed to understand the metabolic differences between mono- and inter-cropped wheat in response to Blumeria graminis f. sp. tritici infection and reveal the physiological mechanism of intercropping for improving wheat resistance to powdery mildew. In this study, the following three nitrogen (N) application levels were established: 75 mg·kg1 (N1), 150 mg·kg1 (N2), and 225 mg·kg1 (N3). Following inoculation with B. graminis f. sp. tritici, the occurrence of powdery mildew in mono- and inter-cropped wheat was investigated, and the metabolomics of mono- and inter-cropped wheat in response to infection with B. graminis f. sp. tritici were analyzed by UPLC-MS/MS, using a widely targeted metabolomic method. The results showed that N levels and N levels × planting patterns significantly affected the incidence and disease indices of powdery mildew in wheat. Under all three N levels, wheat intercropping with faba bean reduced the incidence of wheat powdery mildew by 25.54%–38.81% and decreased the disease index by 18.54%–20.11% relative to mono-cropped wheat (MW), and the intercropping control effect under the N1 level was better than that under N2 and N3 conditions. A total of 822 differential metabolites were detected in the mono- and inter-cropped wheat leaves, of which 69, 52, and 88 were detected at the N1, N2, and N3 levels, respectively. Intercropping of wheat and faba bean regulated flavonoids, alkaloids, amino acids and derivatives, and phenolic acids in wheat leaves compared to MW. Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis of differential metabolites showed that they were mainly enriched in the biosynthesis of amino acids, metabolic pathways, and secondary metabolites. Among them, metabolites with significant differences were enriched in metabolic pathways at the N1 and N2 levels, and metabolites with significant differences were enriched in amino acid biosynthesis under N stress conditions (N1 and N3). Further analysis of the metabolites from the top 10 up- and down-regulated genes revealed that intercropping upregulated glutathione (G-SH), L-tryptophan, L-asparagine, and L-glutamine in wheat leaves at the N1 level relative to MW, and upregulated L-asparagine, L-homomethionine, and L-tryptophan in intercropped wheat leaves at the N3 level relative to MW. In addition, a few metabolites, including alkaloids, phenolic acids, and organic acids, in wheat leaves were regulated by intercropping compared with MW under the N1 and N3 levels. In conclusion, the response of wheat to powdery mildew infection was regulated by N levels. Metabolites involving amino acids and derivatives, alkaloids, phenolic acids, and organic acids in wheat leaves are regulated by intercropping during B. graminis f. sp. tritici infection and induce different physiological reactions, possibly being one of the mechanisms by which intercropping improves wheat powdery mildew resistance. Intercrop-regulated amino acids and their derivatives under N stress are closely associated with wheat powdery mildew resistance. The present study identified the different responses of mono- and inter-cropped wheat to disease infection via metabolic analysis, facilitating a comprehensive understanding of crop diversity for the management of pests and diseases.
Spatiotemporal changes in physiology and total flavonoids of Tetrastigma hemsleyanum in response to blue and purple monochromatic light
LIU Shouzan, JIANG Lingtai, ZHANG Yun, GU Yiwen, HAN Minqi, LI Shan, WANG Hongzhen, BAI Yan
 doi: 10.12357/cjea.20230118
Abstract(65) HTML(42) PDF(1)
Tetrastigma hemsleyanum Diels et Gilg has antitumor, antiviral, and fever-relieving properties. The main active components are flavonoids. It grows in shaded environments in forests, and its growth, development, physiological changes, and synthesis of active components are regulated by short-wavelength light of undergrowth. To explore the spatial and temporal responses of physiological mechanisms and flavonoid synthesis in T. hemsleyanum to short-wavelength light, blue or purple monochromatic light were selected as treatment light sources, and white light was used as the control for 7, 15, 30, 45, and 60 d. The total flavonoid content, flavonoid-related enzymes activities; and physiological and biochemical indexes, such as photosynthetic pigments, anti-resistance enzymes activities, malondialdehyde (MDA), and primary metabolic solubility, of leaves were measured to investigate the spatial and temporal responses of the flavonoid synthesis process and physiological and biochemical changes in T. hemsleyanum to short-wavelength light conditions. The results showed that: 1) short-wavelength light treatments regulated the changes in photosynthetic pigments contents; the control and blue light treatments increased photosynthetic pigments contents, but the purple light treatment significantly inhibited this effect. 2) Continuous monochromatic short-wave light treatments put T. hemsleyanum under mild stress, and the total flavonoid content was the highest with blue light treatment (137.75 mg∙g1 in leaves and 149.00 mg∙g-1 in tubers).The phenylalnine ammonialyase activities in leaves and tubers (96.50 U∙g1 FW, 109.47 U∙g1 FW) and chalcone isomerase activity in leaves (65.17 U∙g1 FW) were highest under purple light treatment; while chalcone synthase activity in tubers was the highest with blue light treatment (46.76 U∙g1 FW). In addition, photosynthetic pigments, resilience, and soluble substances differed in their responsiveness to short-wave light, and both blue and purple light promoted the accumulation of osmoregulatory substances compared with white light. This study provides a theoretical basis and practical guidance for light regulation of T. hemsleyanum quality.
Nitrogen acquirement strategy of different nitrogen forms in two pineapple cultivars
CHEN Xiaohui, XU Xiuyu, FU Liyong, PAN Yanju, FENG Ying, CAI Zhiquan
 doi: 10.12357/cjea.20220857
Abstract(136) HTML(67) PDF(9)
Pineapple [Ananas comosus (Linn.) Merr.] is China’s third largest tropical fruit, with the largest planting area in Xuwen County, Guangdong Province. As one of the most important macronutrients, nitrogen is closely related to pineapple yield. However, the uptake preferences for different nitrogen forms in field-grown pineapple plants remain unclear. In this study, the morphological, physiological, and growth traits of plants with different ages were measured in two field-grown pineapple cultivars (‘Tainang 17’ and ‘Bali’) with different growth periods in April and September, respectively, in Xuwen County. In addition, nitrogen acquisition strategies for three different forms of nitrogen (ammonium nitrogen, nitrate nitrogen, and glycine) in the pineapple roots were determined using the stable isotope 15N tracer technique. The results indicated that the growth period of the ‘Tainang 17’ pineapple (16 months) was shorter than that of ‘Bali’ (20 months). During the fruit harvest period in April, compared with the ‘Bali’ pineapple (796 g fresh fruit weight per plant), ‘Tainang 17’ pineapple plants had lower yield (532 g fresh fruit weight per plant), root biomass, and P content; but had similar plant height, plant biomass per plant, leaf N and K contents, and specific leaf area. As an indicator of long-term water-use efficiency, the δ13C value ranging from −15.16‰ to −13.28‰, was higher in the leaves of ‘Tainang 17’ pineapple than that in ‘Bali.’ Neither cultivar nor age greatly affected the leaf δ13C values. In April and September, there were significant differences in the different forms of nitrogen uptake between the two pineapple cultivars. The nitrogen uptake capacity of ‘Tainang 17’ pineapple was higher than that of ‘Bali.’ The high acquirement capacity of nitrogen and water use efficiency of ‘Tainang 17’ pineapple is attributed to promoting photosynthesis and thus maintaining plant growth in a relatively short life cycle. Both pineapple cultivars preferred to acquire ammonium nitrogen (36.8%–64.6%), followed by glycine (23.2%–47.1%), and the uptake rate of nitrate nitrogen was the lowest (9.1%–31.5%). The nitrogen uptake rate of pineapple plants in the vegetative growth stage (5–8-month-old) was higher than that of plants in the fruit-harvesting stage. However, with increasing plant age, the contribution rate of ammonium nitrogen increased, whereas that of glycine gradually decreased. Across different pineapple cultivars and plant ages, the rates of different forms of nitrogen uptake were not linearly correlated with the soil nitrogen content or measured plant traits. To the best of our knowledge, this is the first study to show that the roots of field-grown pineapple plants can directly absorb organic nitrogen from the soil. Cultivar and plant growth stages of pineapples are important factors that affect nitrogen acquisition strategies. However, the linear relationships between the absorption rates of different forms of nitrogen and soil nitrogen content or measured plant traits were very weak. These results contribute to nitrogen fertilizer management in pineapple plantations.
International research hotspots and emerging trends of agroecology based on WOS
MU Junfang, ZHANG Lixin, YANG Guang
 doi: 10.12357/cjea.20220578
Abstract(333) HTML(49) PDF(21)
In recent years, with continuous changes in the ecological environment, there is a public perception that the promotion of coordinated and sustainable agriculture is much higher than the development of extensive, industrial, and single-oriented agriculture. Agroecology, as an interdisciplinary science at the intersection of ecology and agricultural science, provides a channel to optimize conventional farming systems and ecological agriculture practices, thus becoming a thriving research hotspot in the present day. Therefore, clarifying the research hotspots and emerging trends in international agroecology research helps explain its development and prospects, although there is little in-depth research on this topic. Thus, this study employs the visual analysis software CiteSpace to conduct a bibliometric analysis of the relevant literatures on international agroecology research in the Web of Science from 2012 to 2021. According to this study, three points emerge. The first concerns the research hotspots of international agroecology. Specifically, the analysis of 19 keyword clusters reveal that the research hotspots focus more on the agro-ecosystem’s overall performance and evaluation; for example, the investigation of irreversible influences of climate change, the optimization of climate resilient systems, and the improvement of the field. Moreover, the fundamental and scientific research of ecological agriculture practice gains extensive scholarly focus on agricultural intensification, integrated weed management, soil organic matter, plant function traits etc. Additionally, the social movement of ecological agriculture and its social influence on food security and food sovereignty have been widely investigated. The second point concerns the basic knowledge of agroecology. Through a detailed account of the highly cited references and reference co-citation clustering network, the knowledge base reflects that international agroecology scholars have conducted basic and innovative studies in this field. Notably, the related knowledge base dwells on the ecological transformation and industrial form of ecological agriculture, its social movement, and the adjustment of ecological factors embedded in agricultural ecosystems (e.g., crop diversification, diverse cropping systems, and plant patterns) to construct a sustainable agro-ecosystem. The third point relates to emerging trends in international agroecological studies. Based on burst words and references with subsequent citation bursts, emerging trends highlight agrobiodiversity, biodiversity conservation, landscape ecological security patterns, production systems, and pesticide pollution within the natural sciences. It also involves research in the social management field, specifically the cultivation of knowledgeable farmers, agricultural education, and the connection between indigenous knowledge and modern agro-ecological practices based on participatory action research. Rooted in the national conditions, the future development of domestic agroecology can strengthen international exchanges and cooperation, follow trending international research topics, and comply with the national development strategy and boost the advancement of new agricultural technology, thus enhancing the diversity and sustainability of agro-ecosystems.
Abstract(38) HTML(35) PDF(2)
Agroecosystem and Its Management
Characteristics of structure and abundance of soil nitrogen-fixing bacterial community in alfalfa with different growing ages in the Loess Plateau
WANG Xiaofei, LUO Zhuzhu, LI Lingling, NIU Yining, SUN Pengzhou, HAI Long, LI Linzhi
2023, 31(5): 665-676.   doi: 10.12357/cjea.20220505
Abstract(256) HTML(100) PDF(65)
Biological nitrogen fixation is a major nitrogen source in alfalfa fields, and the nitrogen supply and soil fertility can be largely affected by the composition and quantity of the nitrogen-fixing bacterial community. In this study, a field experiment was conducted to explore the soil nitrogen-fixing bacterial community structure and abundance characteristics in loessal soil with different alfalfa growing ages (2, 9 and 18 years planted in 2019, 2012, and 2003, respectively), using farmland (maize field) as the control. The fluorogenic quantitative real-time PCR technique was adopted in the experiment, using the high-throughput sequencing platform Illumina MiSeq to target the nifH gene. We analyzed the ecological status of abundant and rare nitrogen-fixing microorganisms through co-occurrence networks and identified the dominant factors affecting the community structure of nitrogen-fixing microorganisms by soil coupling the physical and chemical properties. The results showed that long-term planting of alfalfa increased the organic carbon, total nitrogen, and soluble carbon contents of the soil. The nifH gene abundance ranged from 2.97×106 copies∙g−1 to 5.93×106 copies∙g−1 in dry soil and was significantly higher in alfalfa fields than in farmland. The correlation analysis between the abundance of nifH gene of nitrogen-fixing microorganisms and soil physicochemical factors showed that nifH gene abundance in the soil was positively correlated with bulk density (P=0.009) and soluble carbon content (P=0.005), positively correlated with total nitrogen (P=0.044) and available potassium (P=0.013) contents, and negatively correlated with total phosphorus content (P=0.000) and nitrate content (P=0.023). A total of 176 367 valid sequences were obtained, belonging to five phyla, eight classes, 11 orders, 15 families, and 17 genera. Proteobacteria and Cyanobacteria were the dominant phyla, accounting for 95.9%−98.9% and 0.2%−1.8% of the total sequences of the samples, whereas Skermanella and Azohydromonas were the dominant genera, accounting for 82.2%–87.6% and 1.6%–4.6%, respectively. Compared with farmland, continuous alfalfa planting significantly increased the relative abundance of Skermanella, but its’ relative abundance decreased with increasing alfalfa planting years. Long-term cultivation of alfalfa propagated microbial taxa, including Azotobacter, Burkholderia, Frankia, Mesorhizobium, Geobacter, and Bradyrhizobium; whereas Clostridium, Rhodopseudomonas, and Trichormus were sterilized. Redundancy analysis (RDA) showed niche differentiation for the nitrogen-fixing bacterial community in response to environmental factors, but total phosphorus, organic carbon, and nitrate-nitrogen in the soil were the dominant environmental factors for the nitrogen-fixing bacterial community structure. Analysis of the molecular ecological network showed that there were 520 nodes and 4170 edges in the network of nitrogen-fixing microorganisms in maize fields and alfalfa soil, among which 24 nodes belonged to the abundant group, 93 nodes belonged to the rare group, and 403 nodes belonged to the transitional group. There was one internal connection of abundant taxa, 2187 internal connections of transitional taxa, and 358 internal connections of rare taxa. Nitrogen-fixing bacteria have a cooperative relationship in their ecological network, with a relatively stable community structure and strong adaptability to environmental changes. This study provides basic data and a theoretical basis for the diversity of nitrogen-fixing microorganisms in loess soil and the determination of a suitable planting period for alfalfa.
Distribution characteristics of the soil fungi community in the rhizosphere of foxtail millet under different planting patterns
WANG Genquan, HAO Xiaofen, GUO Erhu, YANG Huiqing, ZHANG Aiying, CHENG Qiaolin, QIN Yuzhong, WANG Jun
2023, 31(5): 677-689.   doi: 10.12357/cjea.20220577
Abstract(145) HTML(79) PDF(39)
Continuous cropping obstacles occur in foxtail millet. To understand the effects of continuous cropping of foxtail millet on the soil fungal community structure, we explored the distribution characteristics of the fungal community of the rhizosphere soil using the fungal ITS high-throughput sequencing technology under different cropping strategies, including foxtail millet-maize rotation, foxtail millet continuous cropping for three years and five years, and the abandoned land taken as a control. The results showed that a total of ten phyla, 24 classes, 46 orders, 79 families, 136 genera, and 146 species of fungi were detected in the rhizosphere soil of foxtail millet under different cropping strategies. The population structure was relatively stable at the phylum and class levels. The dominant phyla in the soil mainly consisted of Ascomycota and Basidiomycota, whereas the dominant classes were Sordariomycetes, Dothideomycetes, and Pezizomycetes. At the order level, the relative abundance of Sordariales in the rhizosphere of foxtail millet was two times greater than that in abandoned land. At the family and genus levels, the relative abundance of Mortierellaceae and Mycosphaerellaceae was higher, whereas the relative abundance of Alternaria, Didymella, and Clonostachys was lower in the rotation soil than in the continuous cropping soil. Alpha diversity analysis showed that the fungal abundance of the rhizosphere soil was significantly different under foxtail millet-maize rotation and foxtail millet continuous cropping (P<0.05), and that under that rotation, soil diversity was the highest. Beta diversity analysis revealed that the fungal structures of the rhizosphere soil under continuous cropping for three and five years were similar, and they were different from those under abandoned land or rotating cropping, indicating that the fungal community structure in the rhizosphere soil of foxtail millet changed under different cropping strategies. Correlation analysis showed that alkali-hydrolyzed nitrogen was significantly positively correlated with organic matter (P<0.01) and significantly correlated with available phosphorus and urease activities (P<0.05), while the activity of polyphenol oxidase was positively correlated with available potassium (P<0.05) and significantly positively correlated with the Chao1 index and the observed species index (P<0.01). Redundancy analysis (RDA) indicated that CK were affected by Chaetomium, CR was affected by Mycosphaerella and Microdochium, TC and FC were affected by Botryotrichum, Chaetomidium, and Didymella. LEfSe analysis identified distinctly specific markers in the rhizosphere soil of foxtail millet under different cropping strategies. The markers of rhizosphere soil contained Mortierella and Mycosphaerella for the rotating cropping, Botryotrichum, Didymella, and Clonostachys for three years of continuous cropping, and Alternaria and Didymella for five years of continuous cropping. Overall, the soil fungal community structure under millet-maize rotation cropping, exhibiting more saprophytic fungi and fewer pathogenic fungi, was significantly different from that under foxtail millet continuous cropping, which provided useful information for the study of the continuous cropping obstacles of foxtail millet.
Change of soybean climatic suitability in Northeast China under climate change
HE Liang, MAO Liuxi
2023, 31(5): 690-698.   doi: 10.12357/cjea.20220574
Abstract(173) HTML(138) PDF(67)
Northeast China is a major soybean production region that is profoundly influenced by climate change. It is important to identify how climate change influences agroclimatic resources, agro-meteorological disasters, and climatic suitability for soybean production and plant expansion. In this study, we evaluated the temporal and spatial changes in agroclimatic resources (accumulated temperature, precipitation, and sunshine hours at a rate of 80% climatic guarantee during soybean growing season), agro-meteorological disasters (drought and frost days), and soybean climatic suitability using two climate reference periods (1991−2020 and 1981−2010). Finally, the contribution rates of accumulated temperature, precipitation, and sunshine hours to soybean climatic suitability change were calculated using a statistical method. First, we found that a thermal time ≥ 10 ℃ during the soybean growing season increased by 26−65 ℃·d in the east of Inner Mongolia, southwest and northeast of Heilongjiang, and midwest of Jilin, and increased by 66−182 ℃·d in local regions. Additionally, a thermal time ≥ 10 ℃ during the soybean growing season exhibited an increasing trend from 1981 to 2020 in Northeast China. Moreover, the changes in precipitation and sunshine hours during the soybean growing season had the characteristics of spatial differentiation. Second, the number of frost days during the soybean growing season had decreased in the major region of Northeast China by 1–3 days and by 4–6 days in some local areas. Drought days declined in Heilongjiang and northwest of Jilin by 1–4 days and increased in mideast of Jilin and Liaoning by 1–6 days. Third, the climatic suitability of soybean planting has improved in the eastern Inner Mongolia, west of Heilongjiang and Jilin, and Liaoning, while it had dropped in the middle and east of Heilongjiang and the middle and northeast of Jilin. Finally, the change in sunshine hours was the foremost factor affecting soybean climatic suitability. The secondary factor was thermal time, whereas precipitation had the least contribution. The results indicate that the climatic conditions of soybean in 1991–2020 in Northeast China were more favorable than those in 1981–2010. Farmers in Northeast China adopted the sowing date and soybean cultivar to fully utilize the temperature resource. However, blindly growing soybeans across the accumulated temperate zone was not encouraged because of the increased extent of thermal time.
Crop Cultivation and Physiological Ecology
Effects of optimized fertilization on yield, nutrient balance, and eco-environmental benefits in wheat-maize rotation system
YANG Huimin, YANG Yunma, HUANG Shaohui, YANG Wenfang, XING Suli, YANG Junfang, JIA Liangliang
2023, 31(5): 699-709.   doi: 10.12357/cjea.20220606
Abstract(275) HTML(110) PDF(68)
The wheat-maize rotation system in the North China Plain is the main planting pattern that plays a key role in ensuring food security in China. An 8-year positioning experiment with a randomized block design was performed, comprising three treatments: no-fertilizer application control (CK), optimized fertilizer (OPT), and farmers’ practices (FP). The experiments analyzed the effects of OPT and FP on the yield, nutrient balance, greenhouse gas emissions, and economic benefits of the wheat-maize rotation system. The results showed that the yields of OPT increased by 4.3%, 5.3%, and 4.8% compared to FP in wheat, maize, and year-round rotation, respectively. Accordingly, the partial factor productivity of N increased by 39.1%, 31.7%, and 35.9%, respectively. The partial factor productivity of P increased by 39.1%, 40.4%, and 39.8%, respectively. The partial factor productivity of K was reduced by 47.8%, 47.3%, and 47.6%, respectively. The greenhouse gas emissions were reduced by 21.7%, 21.1%, and 21.4%, respectively. The greenhouse gas emission intensity was reduced by 27.0%, 27.5%, and 27.3%. Net profits increased by 11.2%, 11.4%, and 11.3%, respectively. Agronomy costs were reduced by 3.7%, 2.1%, and 3.1%, respectively. The environmental costs were reduced by 28.4%, 17.3%, and 22.1%, respectively. Compared with the FP treatment, the year-round OPT treatment reduced the surplus of nitrogen by decrement of 105 kg·hm−2, i.e., 46.3%. The surplus phosphorus was reduced by 48 kg·hm−2 i.e., 53.3%. The surplus of K of OPT and FP was 59 kg·hm−2 and −1 kg·hm−2, respectively. OPT met the requirements of crop growth better than FP. At the end of 8 years of wheat-maize rotation, the soil organic matter content in OPT treatment increased by 5.3% compared to that in FP. Compared to that of FP, available K increased and P reduced by 12.3% and 27.8%, respectively. In conclusion, compared with FP treatment, OPT treatment has the advantages of high yield, high profit, and environmental friendliness. Therefore, this study provides a scientific basis for the efficient and green product.
Responses of yield traits and grain filling characteristics of maize to sowing dates and their relationships with meteorological factors
CAO Caiyun, DANG Hongkai, LI Jia, LIU Xuetong, MA Junyong, LI Kejiang, ZHENG Chunlian
2023, 31(5): 710-724.   doi: 10.12357/cjea.20220592
Abstract(188) HTML(100) PDF(41)
This study discussed the influence of sowing dates on maize yield. Under the condition of limited water irrigation, the effects of different sowing dates on yield, yield traits, and grain-filling characteristics of maize of one crop cultivation per year, and the correlation of meteorological factors with yield, yield traits, and grain-filling parameters of maize were studied to provide data-based support for high yield and high-efficiency production in low-plain areas. ‘Xianyu 335’ and ‘Zhengdan 958’ were used in the experiment. Five sowing dates were set: May 5 (SD1), May 20 (SD2), June 5 (SD3), June 20 (SD4), and June 30 (SD5). The results showed that: 1) the sowing date had a significant effect on maize yield, which was affected by variety and climate. The grain yield increased initially, followed by a subsequent decrease with the extension of sowing dates. The two-year average yield of SD1 was the lowest, and that of SD4 was the highest. The difference in yield between SD3 and SD4 was not significant. The high yield of SD4 was mainly due to the high grain number per spike and the 100-grain weight. 2) Path analysis showed that the contribution of yield factors to yield affected each other, and the most direct effect on yield was 100-grain weight. 3) For the variation characteristics of grain weight described by the Logistic model, the determination coefficient, R2, was above 0.98, and the difference was significant at P<0.01. The grain weight was determined by the average grain-filling rate (V) and grain-filling duration (D), and D had the largest direct contribution to the grain weight. 4) From the effect of meteorological factors on yield and yield components, the higher the daily average temperature from sowing to silking and the larger the daily temperature difference (TRAvfm) from silking to maturity, the higher the yield. The more days that had temperatures ≥35 ℃ (D1fa) after 10 days of silking, the higher the daily average temperature (TAvfm) from silking to maturity, and the lower the yield and 100-grain weight. TAvfm had the largest direct contribution to the yield and 100-grain weight, and the effects of various meteorological factors on the yield and grain weight were mutually affected. The main reason for the lower grain weight of SD1 was that the accumulated temperature of ≥10 ℃ during the whole growth period and the accumulated temperature of ≥10 ℃ from sowing to silking were higher, TAvfm was higher, TRAvfm was smaller, the days of D1fa were higher, and D was shorter. SD3 and SD4 had larger TRAvfm, higher V and D values, and higher grain weights. Although the sowing date of SD5 was relatively late, the lower TAvfm resulted in a decrease in the accumulated temperature from silking to maturity, and the filling stage was shortened, thereby reducing the final grain weight. 5) In terms of varieties, the main reasons for the higher yield of ‘Xianyu 335’ compared with ‘Zhengdan 958’ were the higher grain number per spike and 100-grain weight, and the product of V and V×D of ‘Xianyu 335’ were 0.19 mg·grain−1 and 0.73 mg·grain−1 higher than those of ‘Zhengdan 958’, respectively. This showed that selecting varieties with high yield potential and a high filling rate and sowing from early June to middle and late June could optimize meteorological factors during the growth period, thereby increasing grain weight and yield.
Influence of combined application of bioorganic fertilizer and chemical fertilizer on lettuce growth and soil environment
ZHANG Qing, HU Chunsheng, LIU Binbin, ZHANG Yuming, DONG Wenxu, LI Xiaoxin, LIU Xiuping, WANG Jing, ZHANG Ruiyuan, WU Kunyan, WU Jie
2023, 31(5): 725-741.   doi: 10.12357/cjea.20220642
Abstract(143) HTML(53) PDF(40)
Irrational fertilization leads to soil degradation and output decline, and crop waste disposal affects the sustainable development of environment and resources. Bioorganic fertilizer showed outstanding advantages in plant growth promotion and soil fertility cultivation, which is beneficial to efficient utilization of resource and reduction of chemical fertilizer application, as well as the development of vegetable industries. In this study, bioorganic fertilizers specifically for experiment were made by fermentation after inoculating Bacillus licheniformis, B. amyloliquefaciens and B. megaterium into Chinese medicine residues, respectively; and lettuce pot experiment in greenhouse was conducted to explore the influence of bioorganic fertilizer combined with chemical fertilizer on lettuce growth and soil environment. Six treatments were set, including three treatments of bioorganic fertilizer with 80% nitrogen content replacing chemical fertilizer (B. licheniformis + Chinese medicine residue organic fertilizer + chemical fertilizer, B1H; B. amyloliquefaciens + Chinese medicine residue organic fertilizer + chemical fertilizer, B2H; and B. megaterium + Chinese medicine residue organic fertilizer + chemical fertilizer, B4H), one treatment where organic fertilizer with 80% nitrogen content replacing chemical fertilizer (Chinese medicine residue organic fertilizer + chemical fertilizer, H) and chemical fertilizer treatment (CF), as well as no fertilizer treatment (CK). The growth indicators of lettuce, and soil environmental indicators and bacterial diversity were measured and analyzed. The results showed that: the comprehensive effect of fertilization measures on lettuce yield and quality, soil nutrient environment improvement were both ranked as B4H>B2H>B1H>H>CF>CK. Compared with H, the fresh weight and content of chlorophyll, vitamin C and soluble sugar of lettuce in B4H were increased by 10.69%, 17.77%, 47.54% and 10.95%, respectively; while the nitrate content in B4H was decreased by 52.00%. The contents of available phosphorus (AP), available potassium (AK), microbial biomass carbon (MBC) and water dissolved organic carbon (DOC) in B4H were increased by 47.57%, 10.98%, 35.54% and 16.10% respectively. The bacterial species richness and diversity increased by 7.68% and 0.85% respectively in B4H. Soil AP, AK and available nitrogen (AN) were the main factors affecting lettuce growth, while pH, AP and AK were the main regulatory factors on soil bacterial community. Fertilization was beneficial to bacterial Alpha diversity promotion in lettuce rhizosphere soil, and higher bacterial Alpha diversity in rhizosphere soil performed promoting effect on lettuce yield and quality. As a whole, B4H was the optimal fertilization to the improvement of lettuce growth and soil environment. This study proposed new theoretical support to the development of vegetable and bioorganic fertilizer industries, and was conducive to the implementation of green sustainable development strategy.
Effects of nano-Si on tomota plant growth and carbohydrates accumulation at low temperature
GUO Shuxun, DAI Zemin, YANG Ran, JI Chen, SHI Yu, ZHANG Yi
2023, 31(5): 742-749.   doi: 10.12357/cjea.20220773
Abstract(159) HTML(65) PDF(35)
Low temperatures are one of the main limiting factors in the development of agricultural facilities in North China. Farmers need cheap and convenient agronomic measures to improve tomato resistance to low temperatures. The aim of this study was to investigate the effects of nano-Si on root system architecture and the accumulation mechanism of non-structural carbohydrates of tomato seedlings at low temperatures. In this study, the tomato cultivar ‘Zhongza 9’ was cultivated by substrate cultivation and was used as the test material, and the effects of leaf spraying nano-Si (0 mg∙L−1 and 100 mg∙L−1) at room temperature (25 ℃/16 ℃, day/night) and low temperature (15 ℃/6 ℃, day/night) on tomato biomass, root system architecture, photosynthetic capacity, and non-structural carbohydrates contents were studied. The results showed that: 1) At low temperatures, the biomass, total root length, root tips number, photosynthetic pigment content, and net photosynthetic rate of tomatoes were significantly decreased (P<0.05), while the contents of soluble sugar, sucrose, and starch were significantly increased (P<0.05), and shoot fresh weight, net photosynthetic rate, and total root length were decreased by 48.60%, 66.88%, and 65.49%, respectively (P<0.05). 2) Application of nano-Si significantly increased tomato biomass, root activity, root tips number, fractal dimension, net photosynthetic rate, and non-structural carbohydrates contents at room temperature and low temperature (P<0.05), whereas application of nano-Si at low temperatures increased the root tips number, net photosynthetic rate, and leaf soluble sugar content by 35.25%, 48.24%, and 75.69%, respectively (P<0.05). In conclusion, low temperatures severely restrict photosynthesis, root growth, and transport of non-structural carbohydrates in tomato leaves, and root system architecture parameters tend to change in directions that are not conducive to plant growth. The application of nano-Si could improve the cold resistance of tomatoes by promoting the synthesis of photosynthetic pigments, increasing the photosynthetic rate and root activity, improving root system architecture, and increasing the synthesis of non-structural carbohydrates.
Growth and photosynthetic characteristics of different heat-sensitive potato genotypes during the tuberization stage under high-temperature stress
ZHOU Jinhua, LI Youhan, ZHANG Xing, HU Ronghai, GUO Huachun
2023, 31(5): 750-764.   doi: 10.12357/cjea.20220658
Abstract(169) HTML(96) PDF(33)
The potato (Solanum tuberosum L.) is an important grain and vegetable crop. Global warming affects its growth and production owing to its high temperature sensitivity. Investigating the physiological differences between heat-tolerant and heat-sensitive resources can help rationalize the mechanism of high-temperature resistance in potatoes. The parameters related to the morphology and photosynthesis of the heat-tolerant line ‘Dian 187’ (D187) and the heat-sensitive cultivar ‘Qingshu 9’ (QS9) were measured and analyzed after two weeks of high-temperature stress at 30 ℃. Under high-temperature stress, the plant height and internode length were increased, the leaves were upright, the length and area of leaves were reduced, and the plant architecture was more compact. The extent of change in the leaf number and bend angle in D187 was greater than that in QS9. The high-temperature affected potato net photosynthetic rate, water use efficiency, maximum net photosynthetic rate, apparent quantum yield, carboxylation efficiency, maximum carboxylation rate, and maximum electron transport rate, which were lower in QS9 than those in D187 under high-temperature stress. Furthermore, D187 had a lower light compensation point and dark respiration rate than the heat-sensitive cultivar (QS9), and as a result of its strong adaptability, the number of indexes with phenotypic plasticity index exceeding 0.5 in D187 was more than that in QS9. The mean phenotypic plasticity index of morphology, photosynthesis, and yield was 0.448 in D187, which was higher than that in QS9 (0.418). Furthermore, under high-temperature stress, the ability to absorb CO2 and low-concentration CO2 utilization were weakened, along with the acceleration of water loss and the reduction of water use efficiency in potato plants. Consequently, respiratory consumption increased, and the regeneration abilities of ribulose 1,5-diphosphate (RuBP) and chlorophyll fluorescence parameters were reduced in the dark. In contrast, chlorophyll fluorescence parameters increased under light, and the utilization ability of limited light was also enhanced. Differences in morphology and photosynthetic self-adaptation abilities are the main reasons for the difference in high-temperature resistance between heat-tolerant and heat-sensitive resources, which will help clarify the mechanism of high-temperature adaptability in potato plants and provide references for the selection of cultivars with high-temperature resistance and innovation in cultivation techniques.
Agricultural Resources and Environment
Soil nitrate-N distribution, leaching loss and nitrogen uptake and utilization of maize under drip irrigation in different precipitation years
ZHAI Yongquan, MA Kun, JIA Biao, WEI Xue, YUN Binyuan, MA Jianzhen, ZHANG Hao, JI Li, LI Jiarun
2023, 31(5): 765-775.   doi: 10.12357/cjea.20220517
Abstract(155) HTML(108) PDF(35)
To improve crop yield, excessive nitrogen usage in agricultural production has become increasingly important in recent years. Excessive nitrogen use increases soil nitrate-N accumulation and water pollution, and nitrogen leaching loss varies with precipitation year. It is of great significance to clarify the scientific fertilization model in different precipitation year types under drip irrigation in Ningxia to alleviate the problems of resource waste, water quality decline in the Yellow River, and groundwater pollution caused by unreasonable nitrogen usage. In this study, a 3-year nitrogen gradient experiment was carried out in the Pingjipu Farm, Ningxia Hui Autonomous Region, with five nitrogen application treatments: 360 kg∙hm−2 (N4), 270 kg∙hm−2 (N3), 180 kg∙hm−2 (N2), 90 kg∙hm−2 (N1), and 0 kg∙hm−2 (N0), to analyze the effects of different nitrogen fertilization treatments on soil nitrate-N residues and leaching amounts, as well as on nitrogen uptake, utilization, and yield of maize under drip irrigation in rainy and dry years. The results showed that the peak value of soil nitrate-N content was closely related to precipitation; the peak value of nitrate-N residue was in the 40–60 cm soil layer in the rainy year (2018), and in the 20–40 cm soil layer in the dry years (2019 and 2020). In different precipitation years, soil nitrate-N residues, and leaching increased with the increased nitrogen usage and reached the maximum value under the N4 treatment. Precipitation significantly affected nitrate leaching, and in rainy years, the nitrate-N leaching loss caused by precipitation accounted for 50.62% of the total leaching loss, while in the dry year accounted for 34.82% of the total leaching loss. The regression analysis showed that maize yield initially increased and then decreased by the application rate of nitrogen in different precipitation years. The maximum yield was found under 270 kg∙hm−2 (N3) in different precipitation years, and the yield and nitrogen uptake under the N3 treatment did not differ from 360 kg∙hm−2 (N4). In rainy year, compared with N4, the utilization rate, agronomic utilization rate, and partial nitrogen fertilizer productivity increased by 11.38%, 6.16 kg∙kg−1, and 13.85 kg∙kg−1; and in dry years, they were increased by 12.10%, 5.06 kg∙kg−1, and 15.00 kg∙kg−1, respectively. In summary, when the nitrogen application rate was 270 kg∙hm−2, the yield, nitrogen uptake, and utilization of maize in rainy and dry years were maintained at a high level, and the amount of nitrate leaching was also within an acceptable range. It is recommended that 270 kg∙hm−2 is the appropriate nitrogen application rate for maize under different precipitation patterns in the Ningxia Yellow River irrigation area. The maximum threshold of nitrogen usage in the rainy year is 275.59 kg∙hm−2, and that in the dry year is 320.20 kg∙hm−2. The results from this study can provide a theoretical basis for the decision of scientific nitrogen application in different precipitation years of drip-irrigated maize in the Ningxia Hui Autonomous Region.
Determination of water price and estimation of water savings and emission reduction in groundwater irrigation areas: A case study of Nanpi County, Hebei Province
WANG Xiqin, JIANG Zhiqiang, ZHANG Xinyue
2023, 31(5): 776-784.   doi: 10.12357/cjea.20220579
Abstract(167) HTML(58) PDF(18)
A comprehensive reform of agricultural water prices is required to study and propose a reasonable water price adjustment scheme. The method regarding the determination of water price and the estimation of water savings and pollutant emission reduction in groundwater irrigation areas were proposed, and the current irrigation water use and current water price were calculated by using the method of “converting electricity into the water”. The double logarithm model was used to establish the price elasticity function of irrigation water demand. The ideal water price was calculated using the residual value method, and the pollutant emission reduction from water savings was calculated using the farmland pollution logistics loss model. Taking Nanpi County of Hebei Province as an example, the results showed that the current water prices of wheat and corn are 0.44 ¥∙m−3 and 0.48 ¥∙m−3, respectively. The water price elasticity coefficients of wheat and corn are −0.47 and −0.71, respectively. The actual water prices of wheat and corn corresponding to the irrigation quota are 0.52 ¥∙m−3 and 0.77 ¥∙m−3, respectively, and the ideal water prices are 0.84 ¥∙m−3 and 1.01 ¥∙m−3, respectively. As per the recommended scheme, the theoretical water price accounts for less than 15% of the total cost, the increased range for water price of wheat and corn is 0.08 ¥∙m−3 and 0.29 ¥∙m−3, respectively; and the water-saving potential is 235.05 m3∙hm−2, 682.80 m3∙hm−2. The nutrient emission reduction of ammonia nitrogen, total nitrogen, and total phosphorus are 5.2−19.2 g∙hm−2, 52.7−195.4 g∙hm−2, and 4.6−16.9 g∙hm−2 for wheat; and 18.5−27.6 g∙hm−2, 189.1−281.2 g∙hm−2, and 16.3−24.3 g∙hm−2 for corn, respectively. As the comprehensive reform of agricultural water prices is a systematic project, it needs the support of relevant supporting policies. This study suggests the adoption of water-saving technology, land transfer, large-scale operation, and irrigation quota management systems to promote comprehensive reform of agricultural water prices through relevant incentive policies.
Accelerating carbon conversion in garden waste composting with food waste-expanding microbial inoculants
ZHANG Lu, WANG Hongge, WANG Weishuai, WANG Xuan, LI Jing, LI Lin, GUO Weiting, LIU Shuang, WANG Hong, LU Yunli, MA Lin
2023, 31(5): 785-795.   doi: 10.12357/cjea.20220744
Abstract(134) HTML(81) PDF(32)
The expansion of urbanization has resulted in the generation of a large amount of garden waste (40 million tons per year in China), while traditional treatment methods (incineration and landfill) tend to cause serious environmental pollution and waste of resources. Composting is an effective way to realize resource utilization of garden waste. However, the high lignocellulose content of garden waste limits its resource utilization. Accelerating the degradation of lignocellulose in the composting process is of great significance for achieving effective resource utilization of garden waste. Inoculation with exogenous microorganisms is considered an environmentally friendly and cost-effective method to accelerate lignocellulose degradation, which would further reduce the cost of inoculum production and improve inoculation efficiency. In this study, food residues (apple pomace and bean dregs) were used instead of conventional carbon and nitrogen sources (glucose and peptone) to propagate lignocellulose-degrading fungi. The number of viable fungi in the multiplication product reached 3.7×1010 cfu∙mL−1, which increased by 46.2% compared with the traditional industrial medium. The effects of different inoculum amounts (0, 2%, 4%, and 8%, dry weight) on carbon conversion during garden waste composting were also discussed. The inoculation treatments significantly increased lignocellulose degradation (P<0.05), according to the results. The total lignocellulose degradation rates of the 2%, 4%, and 8% inoculation treatments (2%IM, 4%IM, and 8%IM) increased by 6.3%, 9.2%, and 23.0%, respectively, compared with CK. Dynamic changes in humus precursors (reducing sugars and polyphenols) and humus components were further analyzed. The 8%IM treatment accelerated the complete mineralization of carbon, resulting in the complete degradation of the humus precursors (polyphenols and reducing sugars) into CO2, which inhibited humification. Compared with CK, 2%IM, and 4%IM, the cumulative CO2 emissions of 8%IM increased by 21.9%, 22.3%, and 26.0%, respectively. The 4%IM treatment accelerated lignocellulose degradation while promoting the synthesis of humic acid (HA). The final HA content reached 91.3 g∙kg−1, which was 24.9%, 10.7%, and 35.8% higher than that of CK, 2%IM, and 8%IM treatments, respectively. These results indicate that appropriate inoculation is beneficial to the directional transformation of lignocellulose to humic acid, whereas excessive inoculation would lead to an excessive loss of organic matter due to the high metabolic activity of microorganisms; and the degradation efficiency of lignocellulose is lower when inoculated with a small amount, which was further confirmed by the partial least squares path analysis model in this study. The conversion of lignocellulose to dissolved organic carbon increased with increasing inoculation amount (correlation coefficients of CK, 2%IM, 4%IM, and 8%IM were 0.59, 0.70, 0.75, and 0.85, respectively), while the correlation coefficient of 4%IM from DOC to HA was −0.85, which was higher than 2%IM (−0.76) and 8%IM (−0.34). Therefore, the growth and propagation of lignocellulose-degrading fungi can be completely realized by using food residues as a culture substrate. A 4% inoculation amount was more conducive to the humification of garden waste compost and the preservation of carbon. This study provides a reference for the garden waste composting inoculation process and a theoretical basis for multi-source waste-efficient collaborative treatment.
Effects of new acidification methods on nitrogen conversion during agricultural waste composting
ZHANG Lu, WANG Hongge, WANG Weishuai, WANG Xuan, GUO Weiting, LIU Shuang, WANG Hong, MA Lin
2023, 31(5): 796-806.   doi: 10.12357/cjea.20220746
Abstract(124) HTML(55) PDF(34)
Aerobic composting is a common method for treating agricultural waste. However, a large amount of nitrogen is lost during composting, which is an important problem in agricultural waste composting. Material acidification is an effective method to reduce nitrogen loss during composting, while conventional acidification using inorganic acids has disadvantages such as high cost and secondary pollution. Optimizing the acidification process is of great significance for reducing nutrient loss and environmental pollution during composting. In this study, an acid conditioner was prepared by anaerobic fermentation of lactic acid bacteria with food residues (apple pomace and soybean dregs) as substrates, which were rich in lactic acid (70 mmol·L−1) and lactic acid bacteria (106 cfu·mL−1). Two acidizing methods were designed using the acid conditioner: 1) A certain amount of acid conditioner (30%, w/w) was added directly to acidify the material (MA); 2) a small amount of acid conditioner (3%, w/w) was added with no forced ventilation for the first 3 days of composting to enable the lactic acid bacteria under the acidic conditioners to produce lactic acid achieving self-acidification of compost materials (LA). Meanwhile, we set up two experimental treatments consisting of adding sulfuric acid (SA) and no acidification (CK). Changes in physicochemical properties (temperature, pH, electrical conductivity, germination index of Oenanthe javanica treated with different composts, contents of organic matter and total nitrogen) and treansformation of nitrogen forms (emissions of NH3 and N2O; contents of organic nitrogen, NH4+-N, NO2-N, and NO3-N) during the composting of agricultural waste were analyzed. The results showed that the compost products treated by the three acidification methods all reached the maturity standard (germination index > 80%), and the MA treatment was the best (germination index = 117.8%). The duration of the thermophilic phases (> 50 ℃) of CK, MA, SA, and LA were 10, 10, 9, and 7 days, respectively, all of which reached the harmless standard (> 50 ℃ for at least 7 days). The total nitrogen losses of MA, SA, and LA decreased by 14.0%, 25.6%, and 22.2%, and NH3 volatilization decreased by 26.0%, 36.5%, and 54.9%, compared with CK, respectively. The acidification treatments increased the NH4+-N content, promoted nitrification, and indirectly enhanced denitrification. MA and LA treatments reduced N2O emissions by 23.1% and 69.4%, respectively, whereas SA treatment inhibited N2O reduction and increased N2O emissions by 18.3%. The ReCiPe evaluation method was used to evaluate the total environmental burden of different acidification treatments. The total environmental burden of MA, SA, and LA decreased by 34.5%, 11.0%, and 55.9%, respectively, compared with that of CK, indicating that acidification is an effective way to reduce the environmental burden of composting. By comparing the economic benefits of the three acidifying methods, it was found that the costs of MA and LA treatments were 18.4 Yuan and 0.87 Yuan, respectively, for reducing the emission of 1 kg active nitrogen, which was far lower than that of SA treatment at 91.3 Yuan. These results indicate that MA and LA acidification methods are economically feasible. In conclusion, MA and LA treatments can be feasible methods to reduce nitrogen loss during composting. This study provides a new theoretical basis for composting acidification and nitrogen conservation technology as well as a new scheme for the collaborative treatment of multi-source waste.
Agricultural Ecologic Economics and Ecoagriculture
Time variation characteristics of agricultural green development indexes in Lishu County, Jilin Province
HOU Xiangcheng, LI Han, WANG Yin, FENG Guozhong, LIU Yajun, LI Xiaoyu, GAO Qiang
2023, 31(5): 807-819.   doi: 10.12357/cjea.20220189
Abstract(153) HTML(74) PDF(34)
As an advanced agricultural production county in China, Lishu County in Jilin Province has always been at the forefront of green agricultural development; this study took it as a typical case. Through the established indicators system of Chinese agricultural green development, combined with the nutrient flows in food chain, environment and resources use (NUFER) model, it analyzed the characteristics and change rules of agricultural green development indicators in terms of social economy, food production, and ecological environment, from 1994 to 2019, in Lishu County. The driving and restricting factors of county agricultural green development in Jilin Province were further explored. The results showed that the overall level of agricultural green development in Lishu County has improved steadily from 1994 to 2019, with the number proportion of indicators of gradeⅠ and gradeⅡ decreasing from 47% to 23%, and the number proportion of indicators of gradeⅢ and gradeⅣ increasing from 22% to 47%. In terms of social economy, the per capita comprehensive agricultural input and the per capita disposable income of rural residents have increased annually, and the per capita protein intake and the proportion of animal protein production have also improved, both reaching a grade Ⅳ level. Although the power of agricultural mechanization has shown an increasing trend, it is still at levelⅠ and needs to be improved. In terms of food production, the energy consumption per unit agricultural output value and the fertilizer phosphorus absorption utilization in farmland have been at level Ⅳ for many years; however, the comprehensive nitrogen use efficiency of livestock and poultry nitrogen has always been at a low level. The input of pesticides and fertilizer nitrogen reached levelⅢ in 2019; however, it did not increase continuously during the process, which was greatly affected by the years. In terms of the ecological environment, nitrogen emissions, nitrogen surplus, and environmental losses per unit cultivated land area due to nitrogen inputs all showed an improving trend from 1994 to 2019. However, the comprehensive utilization rate of livestock manure and the livestock and poultry carrying capacity per unit area was still at grade I, which meant that the development of the livestock industry still faces great challenges in Lishu County. Above all, the underutilization of resources, the environmental pollution, and ecological damage was caused by a single plantation structure, low yield of high-quality agricultural products, high input of pesticides and chemical fertilizers, and unstable numbers of livestock. It is therefore urgent to develop and utilize black land resources reasonably, to vigorously promote testing soil for formulated fertilization, improve conservational tillage and other excellent agricultural technologies, solve the contradiction between supply and demand of high-quality agricultural products, reduce damage to the ecological environment, and comprehensively promote the green development of agriculture in Jilin Province.
Measurement and analysis of agricultural green total factor productivity based on farmers’ perspectives
CHENG Yongsheng, ZHANG Deyuan, WANG Xia
2023, 31(5): 820-834.   doi: 10.12357/cjea.20220562
Abstract(183) HTML(71) PDF(36)
Improving agricultural green total factor productivity (AGTFP) and hastening agricultural green transformation are unavoidable choices for comprehensively building a strong socialist, modernized country. Based on a comparative analysis of micro-measurement methods, this study analyzed the status of AGTFP at the farmer household level based on the technically optimized Malmquist-Luenberger index. The kernel density estimation method and the Dagum Gini coefficient method were further used to reveal the dynamic evolution of AGTFP and its regional differences in the micro-sample. The main findings are as follows: 1) From the measurement results, the mean value of AGTFP in the microfield in 2014, 2016 and 2018 was 1.0030, with a good overall development trend. The mean value of AGTFP of farmers in 2016 was 1.0099, and agricultural green development had a good growth trend. The mean values of technical efficiency change and technical progress change were 1.0165 and 0.9928, respectively, indicating that the improvement in farmers’ green agricultural technical efficiency was the main driving factor while the change in technical progress was relatively slow. In 2018, the mean value of AGTFP by farmers was 0.9960, which showed a decreasing trend. The corresponding mean values of technical efficiency change and technical progress change were 0.9765 and 1.0200, respectively, indicating that the technical efficiency improvement of green agriculture did not achieve a sustainable spillover effect and that the innovation function of technical progress change played a role in the improvement. 2) In terms of contributing factors, the use of subjective environmental assessment scores or objective provincial-level environmental pollution data as proxies for non-desired outputs among farmers with higher levels of AGTFP, agricultural green technological progress, and agricultural green technological efficiency was found to be more effective. For farmers with high levels of AGTFP, both green technological advances and green technological efficiency in agriculture were drivers of green growth, and the contribution of the latter was greater than that of the former. 3) From the perspective of a dynamic evolution pattern, in terms of AGTFP, the concentration in 2016 and 2018 was high, showing distinct clustering; however, the divergence phenomenon was not obvious, and the number of farmers with a high level of green development in 2018 was much higher than that in 2016; in terms of the agricultural technical efficiency of farmers, there was no bifurcation in 2016 and 2018. The number of low-level farmers in 2018 was higher than that in 2016, indicating that there was a regression phenomenon, and the difference between the agricultural technical efficiency of high- and low-level farmers was obvious. In terms of agricultural green technical progress of farmers, the overall trend was increasing, the number of low-level farmers in 2016 was lower, and the number of high-level farmers was relatively higher, while in 2018, the number of high- and low-level farmers remained the same, and a spatial clustering effect was evident. In 2018, the number of farmers with low levels of agricultural green technology progress decreased “precipitously.” On the premise that the number of farmers remained unchanged, this part of the low-level farmers moved to the middle- and high-level groups, forming the dynamic transfer effect of “internal push and external pull.” 4) From the perspective of regional disparity, the overall gap in AGTFP in the sample period was decreasing, with a decline of 22.32%. From the source decomposition, the hyper-variance density was the main cause of the overall regional disparity in AGTFP. From the contribution rate, the contribution rate of hyper-variance density was much higher than the contribution rate of intra- and inter-regional disparity, indicating that the cross-over problem between different regions was the main cause of the overall disparity in AGTFP at the farmer level. Further, from the intra-regional disparity, the disparity of AGTFP at the household level decreased within the eastern and western regions; from the inter-regional disparity, the disparity between the eastern and western, eastern and central, and central and western regions decreased continuously during the sample period, and the synergy was the highest, but this gap was susceptible to environmental factors.

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
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  • China's Top Science and Technology Periodicals
  • Covered by Chinese Science Citation Database (CSCD)