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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.
The effects of soil moisture on N2O emission from loessial soil in Northwest China were studied by laboratory simulation. The results showed that soil N2O emission increased with the increase of soil moisture at the test temperature. However, except for the WFPS of 20.67% At this time, loessial soil adsorbed N2O in the air, that is, loessial soil may be sink of N2O at low water content.Under the designed soil moisture range, the maximal water effect range of soil N2O emission under the condition of 15 ℃ is 49.18% (WFPS) between 20 and 57.86% (WFPS), between 38.14% and 49.18% (WFPS) at 20 ° C and between 20.67 and 38.14% (WFPS) at 25 ° C, 30 ° C and 35 ° C, That is, with the increase of temperature, the maximum moisture effect range of N2O advanced.The soil N2O cumulative emission (y) kinetic curve was in accordance with the modified Elovich equation (P <0.01), and with the increase of humidity, the apparent emission rate (b ) At 25 ℃, 30 ℃ and 35 ℃, the initial N2O emission (a) also increased with the increase of humidity. Soil moisture (20.67% -57.86% WFPS) increased with the increase of humidity at 15 ℃, 20 ℃ and 25 ℃, The effect of N2O emission on farmland soil samples showed a linear relationship, showing a logarithmic relationship at 30 ℃ and 35 ℃.