%0 Journal Article
%T Effects of N levels on land productivity and N2O emissions in maize-soybean relay intercropping.
%A Fu Z
%A Chen P
%A Li Y
%A Luo K
%A Lin P
%A Li Y
%A Yang H
%A Yuan X
%A Peng X
%A Yang L
%A Pu T
%A Wu Y
%A Wang X
%A Yang W
%A Yong T
%J J Sci Food Agric
%V 0
%N 0
%D 2024 Jul 9
%M 38980001
%F 4.125
%R 10.1002/jsfa.13709
%X <B>BACKGROUND: </B>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.<BR><B>RESULTS: </B>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.<BR><B>CONCLUSIONS: </B>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.