猪粪化肥配施对双季稻田CH4和N2O排放及其全球增温潜势的影响

以湖南典型红壤双季稻田系统为研究对象,采用静态箱-气相色谱法研究了水稻生长季基肥配施猪粪条件下CH4和N2O的排放特征,并估算了排放的CH4和N2O的全球增温潜势(GWP).结果表明,与施用化肥处理相比,猪粪化肥配施对稻田CH4和N2O排放的季节变化模式无明显影响,但影响其排放量大小.两个稻季,猪粪替代50%化学氮肥处理(1/2N+PM)CH4累积排放量较不施氮肥处理(0N)、50%化学氮肥处理(1/2N)、100%化学氮肥处理(N)分别提高54.83%、33.85%和43.30%(P<0.05);1/2N+PM处理N2O累积排放量较N处理显著降低67.50%,较0N处理、1/2N处理分别提高129.43%、119.23%(P<0.05).水稻生长季CH4是GWP的主要贡献者,占CH4和N2O综合GWP的99%以上.1/2N+PM处理的GWP显著高于其他处理(P<0.05),且1/2N+PM处理单位产量GWP最高,较N处理、1/2N处理、0N处理分别提高58.21%、26.82%、20.63%.因此,双季稻田猪粪替代部分化学氮肥较全部施用化学氮肥增加了双季稻田CH4和N2O排放的综合温室效应,其对温室气体排放的影响需在区域温室气体排放清单中加以考虑.

Effects of Combined Applications of Pig Manure and Chemical Fertilizers on CH4 and N2O Emissions and Their Global Warming Potentials in Paddy Fields with Double-Rice Cropping

A field experiment was carried out to study the effects of combined applications of pig manure and chemical fertilizers on CH₄ and N₂O emissions, which were measured using the static chamber/gas chromatography method, and their global warming potentials in typical paddy fields with double-rice cropping in Hunan province. The results showed that the combined applications of pig manure and chemical fertilizers did not change the seasonal patterns of CH₄ and N₂O emissions from paddy soils, but significantly changed the magnitudes of CH₄ and N₂O fluxes in rice growing seasons as compared with sole application of chemical fertilizers. During the two rice growing seasons, the cumulative CH₄ emissions for the pig manure and chemical nitrogen (N) fertilizer each contributing to 50% of the total applied N (1/2N+PM) treatment were higher than those for the treatments of no N fertilizer (0N), half amount of chemical N fertilizer (1/2N) and 100% chemical N fertilizer (N) by 54.83%, 33.85% and 43.30%, respectively (P<0.05), whilst the cumulative N₂O emissions for the 1/2N+PM treatment were decreased by 67.50% compared with N treatment, but increased by 129.43% and 119.23% compared with 0N and 1/2N treatments, respectively (P<0.05). CH₄ was the dominant contributor to the global warming potential (GWP) in both rice growing seasons, which contributed more than 99% to the integrated GWP of CH₄ and N₂O emissions for all the four treatments. Both GWP and yield-scaled GWP for the treatment of 1/2N+PM were significantly higher than the other three treatments. The yield-scaled GWP for the treatment of 1/2N+PM was higher than those for the N, 1/2N and 0N treatments by 58.21%, 26.82% and 20.63%, respectively. Therefore, combined applications of pig manure and chemical fertilizers in paddy fields would increase the GWP of CH₄ and N₂O emissions during rice growing seasons and this effect should be considered in regional greenhouse gases emissions inventory.