Effect of nitrogen fertilizers on methane oxidation in soils by methan otrophs

The paper reviews the effects of the applied amount and the type of nitrogen fertilizers on methane oxidation in soils by methanotrophs and the counteraction of high methane concentration on nitrogen suppression．Soils have a natural ability to fix the allowed extent of exogenous nitrogen through absorption and chelating and so on with soil colloids，etc．and ensure a constant rate of methane consumption from atmosphere．The activity and growth of methanotrophs can be stimulated by appropriate nitrogen addition into soils，but also suppressed by nitrogen more than the critical value fixed by soils．In genera1．methanotroph Type I is more sensitive to environmental disturhation than methanotroph Type．Atmospheric methane oxidation mainly affected by methanotroph Type I and methanotroph Type II in natural soils can be reduced by addition of nitrogen fertilizers into soils，which is a long-term suppression effect and is unreversible，and can not be restored by high methane ratio as such in paddy soils．