Abstract：
BACKGROUND: Relay intercropping of maize and soybean can improve land productivity. However, the mechanism behind N2O emissions in this practice remains unclear. A two-factor randomized block field trial was conducted to reveal the mechanism of N2O emissions in a full additive maize-soybean relay intercropping. Factor A was three cropping systems - that is, monoculture maize (Zea mays L.), monoculture soybean (Glycine max L. Merr.) and maize-soybean relay intercropping. Factor B was different N supply, containing no N, reduced N and conventional N. Differences in N2O emissions, soil properties, rhizosphere bacterial communities and yield advantage were evaluated.
RESULTS: The land equivalent ratio was 1.55-2.44, and the cumulative N2O emission ( C E N 2 O $$ \\mathrm{C}{\\mathrm{E}}_{{\\mathrm{N}}_2\\mathrm{O}} $$ ) was notably lower by 60.2% in intercropping than in monoculture, respectively. Reduced N declined C E N 2 O $$ \\mathrm{C}{\\mathrm{E}}_{{\\mathrm{N}}_2\\mathrm{O}} $$ without penalty on the yield advantages. The relay intercropping shifted soil properties - for example, soil organic matter, total N, NH 4 + $$ {\\mathrm{NH}}_4^{+} $$ and protease activity - and improved the soil microorganism community - for example, Proteobacteria and Acidobacteria. Intercropping reduced C E N 2 O $$ \\mathrm{C}{\\mathrm{E}}_{{\\mathrm{N}}_2\\mathrm{O}} $$ by directly suppressing nirS- and amoA-regulated N2O generation during soil N cycling, or nirS- and amoA-mediated soil properties shifted to reduce C E N 2 O $$ \\mathrm{C}{\\mathrm{E}}_{{\\mathrm{N}}_2\\mathrm{O}} $$ indirectly. Reduced N directly reduced C E N 2 O $$ \\mathrm{C}{\\mathrm{E}}_{{\\mathrm{N}}_2\\mathrm{O}} $$ by decreasing soil N content and reducing soil microorganism activities to alleviate N2O produced in soil N cycling.
CONCLUSIONS: Conducting a full additive maize-soybean relay intercropping with reduced nitrogen supply provides a way to alleviate N2O emissions without the penalty on the yield advantage by changing rhizosphere bacterial communities and soil N cycling. © 2024 Society of Chemical Industry.
RESULTS: The land equivalent ratio was 1.55-2.44, and the cumulative N2O emission ( C E N 2 O $$ \\mathrm{C}{\\mathrm{E}}_{{\\mathrm{N}}_2\\mathrm{O}} $$ ) was notably lower by 60.2% in intercropping than in monoculture, respectively. Reduced N declined C E N 2 O $$ \\mathrm{C}{\\mathrm{E}}_{{\\mathrm{N}}_2\\mathrm{O}} $$ without penalty on the yield advantages. The relay intercropping shifted soil properties - for example, soil organic matter, total N, NH 4 + $$ {\\mathrm{NH}}_4^{+} $$ and protease activity - and improved the soil microorganism community - for example, Proteobacteria and Acidobacteria. Intercropping reduced C E N 2 O $$ \\mathrm{C}{\\mathrm{E}}_{{\\mathrm{N}}_2\\mathrm{O}} $$ by directly suppressing nirS- and amoA-regulated N2O generation during soil N cycling, or nirS- and amoA-mediated soil properties shifted to reduce C E N 2 O $$ \\mathrm{C}{\\mathrm{E}}_{{\\mathrm{N}}_2\\mathrm{O}} $$ indirectly. Reduced N directly reduced C E N 2 O $$ \\mathrm{C}{\\mathrm{E}}_{{\\mathrm{N}}_2\\mathrm{O}} $$ by decreasing soil N content and reducing soil microorganism activities to alleviate N2O produced in soil N cycling.
CONCLUSIONS: Conducting a full additive maize-soybean relay intercropping with reduced nitrogen supply provides a way to alleviate N2O emissions without the penalty on the yield advantage by changing rhizosphere bacterial communities and soil N cycling. © 2024 Society of Chemical Industry.
摘要：
背景：玉米和大豆的中继间作可以提高土地生产力。然而,这种做法中N2O排放背后的机制尚不清楚。进行了双因素随机区组田间试验，以揭示全添加剂玉米-大豆中继间作中N2O排放的机理。因素A是三个种植系统-也就是说，单作玉米(ZeamaysL.)，单一栽培大豆(甘氨酸maxL.Merr.)和玉米-大豆套种。因素B是不同的N供应，不含N,还原N和常规N。N2O排放的差异，土壤性质，对根际细菌群落和产量优势进行了评价。
结果：土地当量比为1.55-2.44，累积N2O排放量（CEN2O$$\\mathrm{C}{\\mathrm{E}}_{{\\mathrm{N}}_2\\mathrm{O}}$$）在间作中明显低于单作60.2%，分别。减少N下降CEN2O$$\\mathrm{C}{\\mathrm{E}}_{{\\mathrm{N}}_2\\mathrm{O}}中继间作改变了土壤特性-例如，土壤有机质，总N,NH4+$${\\mathrm{NH}}_4^{+}$$和蛋白酶活性-并改善了土壤微生物群落-例如，变形杆菌和酸性杆菌。间作通过直接抑制土壤氮素循环过程中nirS-和amoA-调控的N2O生成,减少了CEN2O$\\mathrm{C}{\\mathrm{E}}_{\\mathrm{N}}_2\\\mathrm{O}}$$,或nirS-和amoA-介导的土壤特性转变为间接降低CEN2O$\\mathrm{C}{\\mathrm{E}}_{{\\mathrm{N}}_2\\mathrm{O}}$$。减少N直接减少CEN2O$$\\mathrm{C}{\\mathrm{E}}_{{\\mathrm{N}}_2\\mathrm{O}}$$$通过减少土壤N含量和减少土壤微生物活性来缓解土壤N循环中产生的N2O。
结论：在减少氮供应的情况下进行全加性玉米-大豆中继间作提供了一种通过改变根际细菌群落和土壤氮循环来减轻N2O排放而不损害产量优势的方法。©2024化学工业学会。
结果：土地当量比为1.55-2.44，累积N2O排放量（CEN2O$$\\mathrm{C}{\\mathrm{E}}_{{\\mathrm{N}}_2\\mathrm{O}}$$）在间作中明显低于单作60.2%，分别。减少N下降CEN2O$$\\mathrm{C}{\\mathrm{E}}_{{\\mathrm{N}}_2\\mathrm{O}}中继间作改变了土壤特性-例如，土壤有机质，总N,NH4+$${\\mathrm{NH}}_4^{+}$$和蛋白酶活性-并改善了土壤微生物群落-例如，变形杆菌和酸性杆菌。间作通过直接抑制土壤氮素循环过程中nirS-和amoA-调控的N2O生成,减少了CEN2O$\\mathrm{C}{\\mathrm{E}}_{\\mathrm{N}}_2\\\mathrm{O}}$$,或nirS-和amoA-介导的土壤特性转变为间接降低CEN2O$\\mathrm{C}{\\mathrm{E}}_{{\\mathrm{N}}_2\\mathrm{O}}$$。减少N直接减少CEN2O$$\\mathrm{C}{\\mathrm{E}}_{{\\mathrm{N}}_2\\mathrm{O}}$$$通过减少土壤N含量和减少土壤微生物活性来缓解土壤N循环中产生的N2O。
结论：在减少氮供应的情况下进行全加性玉米-大豆中继间作提供了一种通过改变根际细菌群落和土壤氮循环来减轻N2O排放而不损害产量优势的方法。©2024化学工业学会。
