间作及减量灌溉对农田土壤温室气体排放的互作效应

Interaction effect of intercropping and reduced irrigation on greenhouse gas emissions from farmland soil

基于2014年在甘肃省武威市设置的不同灌水水平与种植模式定位试验,设置两种灌水水平,即减量灌水(495 mm, I1)和传统灌水(540 mm, I2);3种种植模式,即玉米‖豌豆(M‖P)、单作豌豆(P)、单作玉米(M),测定土壤呼吸速率和N_(2)O排放速率,并计算农田温室气体排放总量、全球增温潜势(GWP)和温室气体排放强度(GHGI)。2021—2022两年结果表明:(1)I1和M‖P处理均可显著降低土壤呼吸速率、N_(2)O排放速率、CO_(2)排放总量和N_(2)O排放总量(P<0.05),且减量灌水与间作种植模式交互效应显著(P<0.05);与MPI2处理相比,MPI1处理使土壤呼吸速率、N_(2)O排放速率、土壤CO_(2)排放总量和N_(2)O排放总量分别降低8.39%、33.12%、8.75%和32.84%。(2)I2处理土壤温度和土壤含水量显著高于I1处理(P<0.05);不同种植模式下,整个生育期土壤温度整体表现为M> M‖P> P;相关性分析表明,土壤温度和土壤含水量与土壤呼吸速率和N_(2)O排放速率呈显著正相关关系。(3)灌水水平对作物产量无显著影响(P>0.05),种植模式对作物产量影响显著(P<0.01),表现为M‖P处理产量最高;减量灌水与种植模式交互效应对GWP和GHGI影响显著(P<0.05),MPI1处理较MPI2处理的GWP和GHGI分别降低9.45%和10.00%。在绿洲灌区,减量灌水结合玉米‖豌豆种植模式能够有效提高作物产量并减少温室气体排放,可作为河西灌区推广应用的种植模式。

Based on the positioning experiment of different irrigation levels and planting patterns in Wuwei City,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,N 2O 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^(2)021 and 2022 showed that,(1)Both I1 and M‖P treatments significantly reduced soil respiration rate,N 2O emission rate,total CO_(2) emissions and total N 2O emissions(P<0.05).The interaction between reduced irrigation and intercropping mode was significant(P<0.05).Compared with MPI2 treatment,MPI1 treatment reduced soil respiration rate,N 2O emission rate,total CO_(2) emissions and total N 2O 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 temperature 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 N 2O emission rate.(3)The irrigation 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 irrigation 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 irrigation 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.