Effects of nitrogen fertilizer and straw return on nitrous oxide emission and soil reactive nitrogen fractions in summer maize field
[Objective]This study investigated the effects of nitrogen fertilizer and straw return on ni-trous oxide(N2O)emission and reactive nitrogen fractions in summer maize farmland soils to provide su-pport for establishing a rational and efficient cropping system in Guanzhong,Shaanxi.[Method]The field locating experiment was conducted in Guanzhong,Shaanxi from 2020 to 2022.The trial was set up with two factors of nitrogen application and straw return method.Nitrogen applications included two levels of traditional nitrogen application(N1)and reduced nitrogen application(N0.7),and straw return methods in-cluded two levels of straw not returned to field(S0)and straw returned to field(S)in a randomized block group design.A total of four treatments including traditional nitrogen application+straw returned to field(N1 S),reduced nitrogen application+straw returned to field(N0.7S),traditional nitrogen application+straw not returned to field(N4S0)and reduced nitrogen application+straw not returned to field(N0.7S0)were used to determine soil N2O emission fluxes,soil reactive nitrogen fractions of nitrate nitrogen(NO3-N),ammonium nitrogen(NH4-N),inorganic nitrogen(IN),dissolved organic nitrogen(DON)and microbial biomass nitrogen(MBN),summer maize yield and cumulative N2 O emission per unit of yield.Correlations between soil N2O emission flux and soil reactive nitrogen fractions were also analyzed.[Result]With same nitrogen levels,straw-returned treatments(S)increased soil N2O cumulative emissions,contents of NO3-N,NH4+-N,IN,DON and MBN,summer maize yield and N2 O cumulative emissions per unit of yield,in com-parison to straw-not-returned treatments(S0).With same straw-returned methods,reduced N application treatment(N0.7)reduced soil N2O cumulative emissions,contents of NO3--N,NH4-N,IN,DON and MBN,summer maize yield and cumulative N2 O emissions per unit of yield,in comparison to conventional N application treatments(N1).Compared with the N1S0 treatment,the N1S and N0.7S treatments significant-ly increased summer maize yield and N2O cumulative emissions,and the N0.7S0 treatment significantly de-creased summer maize yield and N2O cumulative emissions.There were highly significant positive correla-tions between soil N2 O emission fluxes and contents of soil NO3--N,NH4+-N,IN,DON and MBN.[Conclu-sion]Compared with the traditional nitrogen application+straw not returned to the field treatment,the traditional nitrogen application+straw returned to the field treatment and the reduced nitrogen application+straw returned to the field treatment had apparent yield increase effects,and the reduced nitrogen applica-tion+straw not returned to the field treatment significantly reduced N2O emission.
万方数据
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