粪肥还田模式对麦田温室气体和氨排放及土壤固碳的影响

Effects of manure returning methods on greenhouse gas and ammonia emissions and soil carbon sequestration in wheat fields

为明确不同类型粪肥还田和水稻秸秆还田对麦田温室气体和氨排放及土壤固碳量的影响,本研究设置化肥+水稻秸秆还田、堆肥配施化肥+水稻秸秆还田、沼液配施化肥+水稻秸秆还田、粪浆配施化肥+水稻秸秆还田和沼液配施化肥+水稻秸秆离田5种处理,分析不同粪肥还田模式对麦田碳氮气体排放、全球增温潜势(GWP)、净全球增温潜势(NGWP)和土壤固碳量的影响。结果表明:粪肥还田处理的累积CO_(2)、CH_(4)、N_(2)O、NH_(3)排放量较化肥+水稻秸秆还田处理基本都有不同程度的增加。不同处理麦田GWP均以N_(2)O排放为主,贡献率为67.4%~74.9%,其中粪浆配施化肥+水稻秸秆还田处理的GWP最高。堆肥配施化肥+水稻秸秆还田处理的麦田NH_(3)累积排放量和气态氮(NH_(3)-N和N_(2)O-N)排放总量最大。沼液配施化肥+水稻秸秆还田处理麦田的GWP和耕层土壤固碳量分别比沼液配施化肥+水稻秸秆离田处理增加20.6%和2.87倍,NGWP由正转负。与化肥+水稻秸秆还田处理相比,粪肥配施化肥+水稻秸秆还田处理可以大幅提高麦田耕层土壤固碳量,且NGWP为负值,其中,粪浆配施化肥+水稻秸秆还田模式的效果最好。本研究结果可为粪肥利用和农田减排固碳提供依据。

In order to clarify the effects of different types of manure returning and rice straw returning on greenhouse gas and ammonia emissions and soil carbon sequestration in wheat fields,five treatments were set up in this study,including chemical fertilizer+rice straw returning,compost combined with chemical fertilizer+rice straw returning,biogas slurry combined with chemical fertilizer+rice straw returning,manure slurry combined with chemical fertilizer+rice straw returning and biogas slurry combined with chemical fertilizer+off-site utilization of rice straw.The effects of different manure returning modes on carbon and nitrogen gas emissions,global warming potential(GWP),net global warming potential(NGWP)and soil carbon sequestration in wheat fields were analyzed.The results showed that the cumulative CO_(2),CH_(4),N_(2)O and NH_(3) emissions of manure returning treatment were basically increased to different degrees compared with chemical fertilizer+rice straw returning treatment.The GWP of wheat fields under different treatments was dominated by N_(2)O emission,with a contribution rate of 67.4%-74.9%,and the GWP of manure slurry combined with chemical fertilizer+rice straw returning was the highest.The cumulative emission of NH_(3) and the total emission of gaseous nitrogen(NH_(3)-N and N_(2)O-N)were the highest in the wheat field treated with compost combined with chemical fertilizer+rice straw returning.The GWP and the carbon sequestration of topsoil in wheat field under the treatment of biogas slurry combined with chemical fertilizer+rice straw returning were 20.6%and 2.87 times higher than those in the treatment of biogas slurry combined with chemical fertilizer+rice straw leaving the field,respectively,and the NGWP changed from positive to negative.Compared with the treatment of chemical fertilizer+rice straw returning,the treatment of manure combined with chemical fertilizer+rice straw returning could significantly increase the amount of carbon sequestration in the topsoil of wheat field,and the NGWP was negative.Among them,the effect of manure slurry combined with chemical fertilizer+rice straw returning method was the best.The results of this study provide a basis for manure utilization,emission-reduction and carbon sequestration in farmland.