关于稻田N2O排放大样本统计分析大多只涉及水分因子和肥料因子,本研究收集历年亚洲稻田N2O排放资料和更多影响阏子(水分管理、肥料类型及用量、土壤属性、气候和水稻类型等)的相关信息,从中筛选出具有统计学意义的因子,构建排放通量和上述因子的统计模型.具有统计学意义的因子包括不同水分管理措施、肥料用量、不同有机肥类型、不同pH和土壤全氮含量交互因子、不同年平均温度和不同水稻类型(P〈0.01),该模型能解释60.7%的N2O排放通量变异,有统计学意义.水分管理措施重要性仅次于肥料用量,其中持续淹水:间歇灌溉:湿润灌溉的相对排放比值为0.17:0.56:1.固氮作物秸秆有效促进N2O排放,厩肥作用不明显,添加秸秆的处理N2O相对排放通量为不添加任何有机肥处理的64%.pH和土壤全氮含量交互作用和排放通量呈显著正相关;pH〉8和年平均气温10~20℃有利于N2O排放.不同水稻类型的N2O排放量差异显著,早稻相对排放通量是中稻的71%,晚稻是中稻的48%,水稻类型能反映种植之前的土壤水分信息.综合考虑更多影响因子能更有利于解释水稻田N2O排放.
Most previous studies attributed variation in N2O emission from paddy fields to water managements and fertilizer input. In this study, we compiled a database of N2O emission from paddy fields in Asia, including water management, type and amount of nitrogen fertilizer, soil property, climate and rice types. After screening the influencing factors with statistical significance (p 〈 0.01 ) such as different water managements, N input, different organic N types, interaction of soil total nitrogen content and different pH levels, different annual temperature levels, and different rice types, a linear model was established to link N2O emission to those factors, which could totally explain up to 60.7% of the observed variation in N2O emission. The most important influencing factor was the amount of N fertilizer input, which had significantly positive correlation with N2O fluxes. Relative emission fluxes of continuous flooding, intermittent irrigation and wet irrigation were 0. 17: 0.56: 1. The soil total nitrogen content had significantly positive effect on NzO fluxes while the optimum pH for N2O emission was pH 〉 8. Straw of N-fixing crop had much higher fluxes than other organic fertilizers while manure had no significant effects on increasing N2O emission. Application of other crop straws actually reduced N2O emission by 36% , as compared with fields without organic N input. The relative fluxes for early rice and later rice were 71% and 48% of that for single rice, respectively. Inclusion of more influencing factors such as soil property, climate and rice type helped explaining more of the variations in the observed N2O emission from paddy fields.