Interaction effect of intercropping and reduced irrigation on greenhouse gas emissions from farmland soil
Based on the positioning experiment of different irrigation levels and planting patterns in Wuwei Cit-y,Gansu Province in 2014,two irrigation levels of reduced irrigation(495 mm,I1)and conventional irrigation(540 mm,I2)and three cropping patterns with maize intercropping with pea(M || P),monocropping peas(P)and monocropping maize(M)were set up.Soil respiration rate,N2O emission rate,total greenhouse gas emissions from farmland,global warming potential(GWP),and greenhouse gas emission intensity(GHGI)were measured.The two-year results from 2021 and 2022 showed that,(1)Both I1 and M || P treatments significantly reduced soil respiration rate,N2O emission rate,total CO2 emissions and total N2O emissions(P<0.05).The interaction be-tween reduced irrigation and intercropping mode was significant(P<0.05).Compared with MPI2 treatment,MPI1 treatment reduced soil respiration rate,N2O emission rate,total CO2 emissions and total N2O emissions by 8.39%,33.12%,8.75%and 32.84%,respectively.(2)The soil temperature and soil water content of I2 treatment were significantly higher than those of I1 treatment(P<0.05).Under different planting patterns,the overall soil temper-ature was M>M || P>P during the whole growth period.Correlation analysis showed that soil temperature and soil water content were significantly positively correlated with soil respiration rate and N2O emission rate.(3)The irriga-tion level had no significant effect on crop yield(P>0.05),while the planting mode had a significant effect on crop yield(P<0.01),indicating that M || P treatment yields were the highest.The interaction effect between reduced ir-rigation and planting pattern had a significant effect on GWP and GHGI(P<0.05),and compared with MPI2,the GWP and GHGI of MPI1 treatment were significantly reduced by 9.45%and 10.00%,respectively.In oasis irriga-tion area,reduced irrigation combining with maize intercropping with pea planting pattern effectively increased crop yield and reduced greenhouse gas emissions and should be used as a planting pattern for promotion and application in oasis irrigation area.
intercroppingreduced irrigationsoilgreenhouse gas emissionmaizepea