Improving crop yield and N utilization while mitigating environmental pollution is a key goal in sustainable agriculture.Integrating green manure with reduced chemical N application is a promising strategy to enhance ...Improving crop yield and N utilization while mitigating environmental pollution is a key goal in sustainable agriculture.Integrating green manure with reduced chemical N application is a promising strategy to enhance N utilization efficiency and minimize reactive N losses.However,the agronomic mechanisms through which green manure incorporation affects soil N retention and N loss under reduced N application remain unclear.This study aimed to uncover the compensatory mechanisms of green manure in improving wheat yield and N utilization under reduced N application,and to identify the principles behind reduced N loss in wheat fields.We conducted a split-plot experiment in the Hexi Oasis irrigation area of Northwest China from 2019 to 2024,using two cropping systems(W,fallow after wheat;W-G,green manure returning after wheat)combined with three N application levels(N1,local conventional N application rate;N2,N-reduction 15%;N3,N-reduction 30%).Our results demonstrated that green manure returning improved soil quality and compensated for the yield and N use efficiency losses caused by 15%chemical N reduction.Specifically,compared to the W-N1,W-GN2 increased soil organic matter content and soil water content by 6.5%and 9.4%,respectively,while reducing soil bulk density and pH by 8.9%and 6.7%.Meanwhile,W-GN2 increased soil nitrate N and total N content in the 0–40 cm soil layer by 8.4%and 8.7%,respectively.Moreover,W-GN2 reduced NH3 volatilization by 13.8%,N_(2)O emissions by 8.8%,and N leaching by 9.4%.It also enhanced microbial biomass N by 50.7%,urease activity by 10.2%,and decreased nitrate and nitrite reductase activities by 19.9%and 32.6%,respectively.Additionally,W-GN2 improved soil bacterialα-diversity and increased the abundance of functional bacteria.Green manure can sustain wheat yield and improve N utilization efficiency under reduced chemical N input by improving the soil environment,enhancing soil N retention and minimizing N losses,which presents a sustainable,yield-stabilizing strategy for Oasis agroecosystems in northwestern China.展开更多
基金financial support of the Science and Technology Program in Gansu province(25JRRA347,24ZDNA008)the Natural Science Foundation of China(32372238,U21A20218,32460547)+4 种基金the Industrial Support Project of Educational Committee of Gansu province(2025CYZC-037)the Research Program Sponsored by State Key Laboratory of Aridland Crop Science(GSCS-2023-Z03)the Agricultural Research System of China(CARS-22-G-12)China Agricultural University Corresponding Support Research Joint Fund(GSAU-DKZY-2024-001)the UPTAKE Project on EU Horizon(101081521).
文摘Improving crop yield and N utilization while mitigating environmental pollution is a key goal in sustainable agriculture.Integrating green manure with reduced chemical N application is a promising strategy to enhance N utilization efficiency and minimize reactive N losses.However,the agronomic mechanisms through which green manure incorporation affects soil N retention and N loss under reduced N application remain unclear.This study aimed to uncover the compensatory mechanisms of green manure in improving wheat yield and N utilization under reduced N application,and to identify the principles behind reduced N loss in wheat fields.We conducted a split-plot experiment in the Hexi Oasis irrigation area of Northwest China from 2019 to 2024,using two cropping systems(W,fallow after wheat;W-G,green manure returning after wheat)combined with three N application levels(N1,local conventional N application rate;N2,N-reduction 15%;N3,N-reduction 30%).Our results demonstrated that green manure returning improved soil quality and compensated for the yield and N use efficiency losses caused by 15%chemical N reduction.Specifically,compared to the W-N1,W-GN2 increased soil organic matter content and soil water content by 6.5%and 9.4%,respectively,while reducing soil bulk density and pH by 8.9%and 6.7%.Meanwhile,W-GN2 increased soil nitrate N and total N content in the 0–40 cm soil layer by 8.4%and 8.7%,respectively.Moreover,W-GN2 reduced NH3 volatilization by 13.8%,N_(2)O emissions by 8.8%,and N leaching by 9.4%.It also enhanced microbial biomass N by 50.7%,urease activity by 10.2%,and decreased nitrate and nitrite reductase activities by 19.9%and 32.6%,respectively.Additionally,W-GN2 improved soil bacterialα-diversity and increased the abundance of functional bacteria.Green manure can sustain wheat yield and improve N utilization efficiency under reduced chemical N input by improving the soil environment,enhancing soil N retention and minimizing N losses,which presents a sustainable,yield-stabilizing strategy for Oasis agroecosystems in northwestern China.
