Effects of Chemical Fertilizers Substitution by Biogas Slurry on CH_4 and N_2O Emissions and Their Greenhouse Effects in Wheat Field

Emissions of CH4and N2O from the wheat fields were measured in situ using the method of static chambers and gas chromatographic techniques,and the greenhouse effect of CH4and N2O were assessed by using global warming potentia(l GWP).The field experiments results clearly demonstrated that the emissions of CH4and N2O from the wheat fields were significantly greater for chemical fertilizer with straw treatment than that for chemical fertilizer treatment.Moreover,the GWP and GWP per yield were significantly increased with chemical fertilizer with straw treatment compared to chemical fertilizer treatment by 57.90% and 52.00%,respectively.While,compared with chemical fertilizer treatment,the values of GWP and GWP per yield were decreased by 25.39% and 24.16% under biogas slurry treatment,and by 10.88% and 10.97% under half biogas slurry with half chemical fertilizer treatment,respectively.This could be explained that lower N2O emissions were obtained under biogas slurry and half biogas slurry with half chemical fertilizer treatments contrasted to chemical fertilizer treatment.In addition,lower greenhouse effects of CH4 and N2O emissions were obtained in biogas slurry and half biogas slurry with half chemical fertilizer treatments in contrast to chemical fertilizer and chemical fertilizer with straw treatments during wheat season in the rice-wheat rotation system.