草原土壤N2O释放及全球变暖影响下土壤养分变化的反馈效应

对草原土壤N₂O释放及其受全球变暖土壤养分变化的影响研究表明,以沼泽泥炭土N₂O释放量最大,生长季节为1.3～12.2kgN·hm^-2·a^-1,其次灰壤土,为1.5～2.4kgN·hm^-2·a^-1,酸性棕壤最小,为0～3.2kgN·hm^-2·a^-1;N₂O的释放层灰壤土在0～5cm,其它2种土壤为0～10cm;施肥试验表明,N、P肥在生长季节对土壤N₂O释放量影响不显着,但在生长季末期,N肥对酸性棕壤及灰壤土N₂O影响显着,施肥后第3天酸性棕壤由对照的1.3提高到44.2kgN·hm^-2·a^-1,灰壤土则由对照的1.9提高到31.1kgN·hm^-2·a^-1,说明全球变暖对土壤有机质分解的影响不会诱发N₂O释放量的大幅度增加.

N2O emission from grassland soils and the teedback effect or nutrient changes resulting from global warming

Studies on N₂O emissions from grassland soils and its influence by nutrient changes resulting from global warming show that in growing season peaty gley soil has a maximtun N₂O emission varying from 1.3 to 12.2 kg N·hm^-2·yr^-1, N₂O emission in ndcropodzol soils is from 1. 5 to 2.4 kg N·hm^-2· yr^-1, and acid brown earth has the lowest ranging from 0 to 3.2 kg N·hm^-2·yr^-1.N₂O emission mainly comes from top 5cm in micropodzol soil, and from top 10cm in other two soils. Fertilizer application in growing season doesn't make any differece in different soils. However, N application greatly stimulates the N₂O emission at the end of the growing season. And in acid brown earth and in micropodzol soil, it reached respectively 44.2and 33.1 kg N·hm^-2·yr^-1 compared to 1.3 and 1.9 kg N·hm^-2·yr^-1 in the control. This implies that the influence of global warming upon decomposition of organic matters doesn't result in a significant increase in N₂O emission.