氮肥对旱地土壤甲烷氧化能力的影响

甲烷是重要的温室气体之一，对全球变暖的贡献率是20％。大气中甲烷浓度的迅速增加与甲烷的源和汇的不平衡有关。土壤中存在甲烷氧化菌，在一定条件下可以氧化大气中的甲烷。不过土壤对甲烷的氧化能力受一些农业生产活动的影响。氮肥的施用对土壤甲烷氧化有一定的影响。长期定位施肥实验的结果表明氮肥对土壤甲烷氧化的影响主要来源于铵态氮而不是硝态氮，因为氨对甲烷氧化有着竞争性抑制作用。此外，长期施用氮肥还改变了土壤微生物的区系及其活性，从而降低甲烷的氧化速率。氮肥施用的短期效应则与土壤的耕作管理历史、土壤性质、氮肥施用量等因素有关。有机肥对土壤甲烷氧化的影响比化肥要低得多，其物理化学性质及施用方法的不同都会影响到土壤对甲烷的氧化。

Effects of fertilization on the potential of methane oxidation in upland soil

Methane is an important greenhouse gas second only to carbon dioxide and it accounts for 20% of the global warming. Methane concentration in the atmosphere increases rapidly due to the unbalance of methane sources and sinks. Soils can oxidize atmospheric methane under particular condition due to methanotroph exist in soils. However, agricultural activities impact soil methane oxidation potential. Nitrogen fertilization is one of the important factors that inhibit methane oxidation in soils. Long-term fertilization experiments showed that it was ammonium not nitrate that inhibited methane oxidation in soil. Because ammonium and methane molecule bear a similar size that leads a competing inhibition between methane and ammonium oxidation. In addition, repeated ammonium application causes a shift of soil microbes?population and their activities. Short-term effect of nitrogen fertilization on methane oxidation may be dependent on the soil management practice, soil physical and chemical properties, and the amount of fertilizer used. Organic manure also has an impact on soil methane oxidation; however, it is dependent on the property of the organic matter and the method of the application.