【摘要】 通过室内模拟试验,研究湿度对西北地区黄绵土N2O排放的影响.结果表明:在试验温度下,随着土壤湿度增加,土壤N2O排放量增加;但土壤孔隙含水量(WFPS)为20.67%时例外,此时黄绵土对空气中N2O有吸附现象,即在低含水量时,黄绵土有可能是N2O的汇.在试验设计的土壤湿度范围内,15℃条件下土壤N2O排放的最大水分效应区间在49.18%～57.86%(WFPS)之间,20℃条件下在38.14%～49.18%(WFPS)之间,25℃、30℃和35℃时累积量湿区在20.67%～38.14%(WFPS)之间,即随着温度的升高,N2O的最大水分效应区间提前.土壤N2O累积排放量(y)动力学曲线符合修正的Elovich方程(P<0.01),随着湿度的增加,表观排放速率(b)增大,25℃、30℃和35℃时,N2O初始排放量(a)也随着湿度增加而增大;15℃、20℃和25℃时,土壤湿度(20.67%～57.86%WFPS)对农田土样N2O排放总量的作用表现为线性关系,30℃和35℃时表现为对数关系.更多还原

【Abstract】 A laboratory incubation experiment was conducted to study the effect of soil moisture on N2O flux from loessial soil in northwest China.Under the temperature conditions of this experiment,N2O flux increased as soil moisture increased.An exception occurred at a soil moisture content of 20.67% WFPS(Water-Filled Pore Space).At this point,N2O Absorption occurred.This indicated that loessial soil might become a N2O sink when soil moisture is low.The maximum moisture effect on N2O emission from soil was between 49.18%～57.86% WFPS at 15℃,ranging from 38.14% to 49.18% WFPS at 20℃,and from 20.67% to 38.14% at 25℃,30℃ and 35℃,that is,when the temperature increased,the maximum moisture effect of N2O emission from soil shifted forward(to smaller value).A kinetic curve of cumulative N2O flux was fit using the revised Elovich equation.The flux rate increased as soil moisture increased.Initial N2O flux increased as soil moisture increased at 25,30 and 35℃.At 15,20 and 25℃,there was a linear correlation between soil moisture(20.67%～57.86%WFPS) and total N2O flux from farmland,and at 30℃ and 35℃ a logarithmic correlation was observed.更多还原