土壤空气的组成特点( soil air composition) 2.土壤空气中O2<<近地层大气中O2( oXygen) 原因:微生物和根糸等土壤中生物呼吸消耗。 3.土壤空气中水汽压高于近地层大气中水汽压。土壤空气几乎为水气饱和的。 因为土壤湿度均在“最大吸湿量“之上。 4.土壤空气中有少量的还原性气体(恨量气体)。特别是土壤通气不良肘,含有 CH4、H2S、H2、N2O、C2H、PH3、CS2等还原性气体和温室效应气体。大气中 这些还原性气体少。 Soil air the part of ground air that is in the soil and is similar to the air of the atmosphere but depleted in oxygen content and enriched in carbon dioxide Alternatively, the gaseous phase of soil is called soil air. In a completely dry soil most of the pores are filled with air. As the soil water content increases the amount of air in the soil decreases The composition of air in an well-aerated soil is close to the composition of atmospheric air, as the oxygen consumed in the soil by plants and micro-organisms is readily replaced from the atmosphere. However, in a poorly aerated soil, the composition of air differs from the atmospheric air一.土壤空气的组成特点（soil air composition) 2.土壤空气中O2<<近地层大气中O2（oxygen） 原因：微生物和根系等土壤中生物呼吸消耗。 3.土壤空气中水汽压高于近地层大气中水汽压。土壤空气几乎为水气饱和的。 因为土壤湿度均在“最大吸湿量“之上。 4.土壤空气中有少量的还原性气体（恨量气体）。特别是土壤通气不良时，含有 CH4、H2 S、H2、N2O、C2H6、PH3、CS2等还原性气体和温室效应气体。大气中 这些还原性气体少。 Soil Air the part of ground air that is in the soil and is similar to the air of the atmosphere but depleted in oxygen content and enriched in carbon dioxide. Alternatively, the gaseous phase of soil is called soil air. In a completely dry soil most of the pores are filled with air. As the soil water content increases the amount of air in the soil decreases. The composition of air in an well-aerated soil is close to the composition of atmospheric air, as the oxygen consumed in the soil by plants and micro-organisms is readily replaced from the atmosphere. However, in a poorly aerated soil, the composition of air differs from the atmospheric air