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Measurement, spatial spillover and influencing factors of agricultural carbon emissions efficiency in China
WU Haoyue, HUANG Hanjiao, HE Yu, CHEN Wenkuan
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Effects of tillage and straw returning method on the distribution of carbon and nitrogen in soil aggregates
ZHANG Yuming, HU Chunsheng, CHEN Suying, WANG Yuying, LI Xiaoxin, DONG Wenxu, LIU Xiuping, PEI Lin, ZHANG Hui
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Relationship between policy incentives, ecological cognition, and organic fertilizer application by farmers: Based on a moderated mediation model
SANG Xiance, LUO Xiaofeng, HUANG Yanzhong, TANG Lin
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Spatio-temporal evolution of carbon stocks in the Yellow River Basin based on InVEST and CA-Markov models
YANG Jie, XIE Baopeng, ZHANG Degang
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Effects of straw returning and fertilization on soil bacterial and fungal community structures and diversities in rice-wheat rotation soil
ZHANG Hanlin, BAI Naling, ZHENG Xianqing, LI Shuangxi, ZHANG Juanqin, ZHANG Haiyun, ZHOU Sheng, SUN Huifeng, LYU Weiguang
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2023, 31(5): 665-676.
doi: 10.12357/cjea.20220505
Abstract:
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.
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.
2023, 31(5): 677-689.
doi: 10.12357/cjea.20220577
Abstract:
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.
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.
2023, 31(5): 690-698.
doi: 10.12357/cjea.20220574
Abstract:
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.
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.
2023, 31(5): 699-709.
doi: 10.12357/cjea.20220606
Abstract:
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.
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.
2023, 31(5): 710-724.
doi: 10.12357/cjea.20220592
Abstract:
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.
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.
2023, 31(5): 725-741.
doi: 10.12357/cjea.20220642
Abstract:
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.
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.
2023, 31(5): 742-749.
doi: 10.12357/cjea.20220773
Abstract:
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.
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.
2023, 31(5): 750-764.
doi: 10.12357/cjea.20220658
Abstract:
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.
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.
2023, 31(5): 765-775.
doi: 10.12357/cjea.20220517
Abstract:
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.
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.
2023, 31(5): 776-784.
doi: 10.12357/cjea.20220579
Abstract:
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.
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.
2023, 31(5): 785-795.
doi: 10.12357/cjea.20220744
Abstract:
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.
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.
2023, 31(5): 796-806.
doi: 10.12357/cjea.20220746
Abstract:
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.
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.
2023, 31(5): 807-819.
doi: 10.12357/cjea.20220189
Abstract:
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.
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.
2023, 31(5): 820-834.
doi: 10.12357/cjea.20220562
Abstract:
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.
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
- Chinese core periodicals
- Core Chinese Sci-Tech Periodicals
- China's Top Science and Technology Periodicals
- Covered by Chinese Science Citation Database (CSCD)
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