森林土壤是大气温室气体重要的源和汇，主要的温室效应气体CO2、CH4及N2O都直接或间接与这个系统有关。

Forest soil is the important source and sink of greenhouse gas in atmosphere. The main greenhouse effect gases, such as CO2, CH4 and N2O, are related to this system directly or indirectly.

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人类通过改变土地利用方式，大量施用化肥等活动正在改变着土壤作为温室气体源和汇的强度。

However, as a source and a sink as well, soil is being changed because of human activities, such as changing land use and applying fertilizers.

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