配施猪粪对麦季CH4和N2O排放及温室效应的影响

采用遮光密闭箱和气相色谱法研究配施猪粪条件下麦季CH4和N2O的排放特征,并运用全球增温潜势(PGW)对麦田CH4和N2O排放的温室效应进行估算。结果表明,常规施肥、秸秆还田、50%猪粪和100%猪粪替代化肥处理CH4平均排放通量分别为6.10、10.26、5.32和2.35μg.m-2.h-1,N2O平均排放通量分别为24.25、38.24、12.21和16.06μg.m-2.h-1。CH4排放通量在拔节后随温度升高而增加,N2O排放主要发生在苗期灌溉或降水后。与常规施肥相比,100%猪粪和50%猪粪替代化肥处理麦季CH4和N2O排放产生的总PGW分别降低34.3%和48.9%,单位产量的PGW分别降低26.0%和48.9%,秸秆还田措施的PGW及单位产量的PGW分别提高57.9%和52.0%。然而,与常规施肥与秸秆还田处理相比,100%猪粪处理的小麦产量显著降低(P<0.05)。试验结果表明,在作物高产、稳产要求下,50%猪粪替代化肥措施的减排效果较好。

Effects of Application of Pig Manure in Combination With Chemical Fertilizers on CH4 and N2O Emissions and Their Greenhouse Effects in Wheat Field

Characteristics of CH4 and N2 O emissions from wheat fields applied with pig manure in combination with chemical fertilizers were studied using the static chamber method and gas chromatography,and greenhouse effect of the CH4 and N2 O emitted from the fields were assessed using global warming potentials(PGW).Results show that the average CH4 flux from Treatment NPK(the plots applied with chemical fertilizer as in conventional practice),Treatment NPKS(the plots applied with chemical fertilizer plus straw),Treatment 50% PM(the plots applied with half pig manure and half chemical fertilizer) and Treatment 100% PM(the plots applied with pig manure only) was 6.10,10.26,5.32 and 2.35 μg·m-2·h-1,respectively,the average N2 O flux from Treatments NPK,NPKS,50% PM and 100% PM was 24.25,38.24,12.21 and 16.06 μg·m-2·h-1,respectively.It was found that CH4 flux increased with temperature after the elongation stage,and N2O emissions occurred mainly after irrigation or rain during the seeding stage.Compared to Treatment NPK,Treatment NPKS was 57.9% and 52.0% higher in PGW and PGW per yield,respectively,while,Treatment 100% PM was 34.3% and 26.0% lower and Treatment 50% PM 48.9% and 48.9% lower in PGW and PGW per yield,respectively.However,compared with Treatments NPK and NPKS,Treatment 100% PM was significantly lower in wheat yield.It is,therefore,concluded that Treatment 50% PM,that is,to replace half of the rate of chemical fertilizer applied in conventional practice with pig manure,is a good option to reduce CH4 and N2 O emissions from wheat fields without significant yield reduction.