Effects of returning green manure residues of vetch and ryegrass on greenhouse gas emission in dryland soil
Using vetch and ryegrass residues as green manures,two 63 d incubation experiments were conduc-ted to test the impacts of green manure application rate(0,1,2,4,6 t·hm-2)and the residual mix ratio(100％vetch,75％vetch+25％ryegrass,50％vetch+50％ryegrass,25％vetch+75％ryegrass,and 100％ryegrass at a rate of 4 t·hm-2)on soil CO2,N2O,and CH4 emissions.Soil green gas emissions were measured using a gas chromatography.The results indicate that:(1)Compared to the control without green manure,application of green manure significantly increased the accumulative emissions of CO2 and N2O and global warming potential(GWP)by 11.3％～80.2％,15.8％～51.1％,and 11.9％～79.4％(P＜0.05),respectively.Soil CO2 and GWP increased,but CH4 uptake decreased linearly with the increase of application rates.However,soil N2O emission varied in a poly-nomial way with the increase of application rates and peaked at the rate of around 3 t·hm-2.At the same rate,ap-plication of ryegrass residue had a greater CO2 emission and CH4 uptake,while a lower N2O emission than that of vetch residue;(2)Soil greenhouse gas emissions were also correlated with the proportion of ryegrass residues in the mixture with vetch residues.Soil CO2 emission and GWP increased by 5.8％～19.7％(P＜0.05)and 5.3％～17.7％(P＜0.05),while N2O emission and CH4 uptake decreased with the increases of ryegrass residues in the mixture by 11.2％～41.5％(P＜0.05)and 13.4％～50.9％(P＜0.05).Overall,selecting green manure residues with a lower proportion of non-leguminous crops and returning them to the field with lower biomass could achieve ecological ben-efits while maintaining low GWP.
vetchryegrassreturning green manure residuesgreenhouse gas emissionsglobal warming po-tential
万方数据
维普
