农田温室气体N_2O释放的水热效应机理初探

Mechanism of N_2O Emission Relying on Humidity and Temperature from Soil

利用室内试验研究了农田温室气体N2O释放的水热效应机理。结果表明,西北干旱半干旱地区褐土在较低的湿度范围内(3%～22%),土壤中N2O释放速率与土壤湿度呈正相关;土壤湿度接近田间持水量(22%)时,释放速率最大;超过田间持水量(40%)时,N2O释放速率越来越弱。在较低的湿度范围内(3%～22%),30℃时土壤中N2O的释放速率大于10℃时的;超过田间持水量(40%)时,30℃时土壤中N2O的释放速率小于10℃时的。干燥土壤(3%)存在吸收N2O的现象。

Preliminary mechanism of N2O emission relying on both water contents and temperature in soil was studied in our lab. The results showed: soil N2O emission rate increased with increase of soil water regime (from 3% to 22% ), and it turned weaker and weaker when water content exceeded the soil water capacity (40% ) in the drab soil of northwestern arid and semiarid areas. The highest emission rate occurred in soil water capacity. Soil N2O emission rate was higher at 30℃ than that at 10℃ in the lower soil water regime (from 3 to 22% ). However, the trend was opposite when over the soil water capacity (40% ). Also, the wind drying soil could absorb N2O weakly in the incubation experiments.