中文摘要：

为研究模拟酸雨对冬小麦-大豆轮作农田土壤呼吸、硝化和反硝化作用的影响,在农田进行随机区组试验,布设4个区组,每块区组随机设置4个模拟酸雨处理,分别为去离子水A1（pH=6.7）、A2（pH=4.0）、A3（pH=3.0）、A4（pH=2.0）。采用LI-8100开路式土壤碳通量测量系统对不同酸雨强度的冬小麦-大豆轮作农田进行土壤呼吸速率观测,并采用气压过程分离技术（BaPS）测定不同酸雨处理的土壤CO2产生速率、硝化速率和反硝化速率。试验结果表明,冬小麦田各处理间土壤呼吸速率无显著差异（P〉0.05）;大豆田高强度模拟酸雨A4处理明显抑制了土壤呼吸作用（P〈0.05）。就冬小麦-大豆轮作生长季而言,各处理土壤呼吸速率无显著差异（P〉0.05）,其平均土壤呼吸速率分别为（2.26±0.11）、（2.31±0.20）、（1.91±0.09）、（2.03±0.17）μmol·m-2·s-1。冬小麦田A1、A3、A4处理间土壤CO2产生速率、硝化速率和反硝化速率均无显著性差异（P〉0.05）。高强度模拟酸雨抑制了大豆田土壤CO2产生速率;大豆田A1、A3、A4处理的硝化速率测定均值分别为（191.6±36.1）、（261.6±36.3）μg·kg-1·h-1和（255.2±45.1）μg·kg-1·h-1,这3个处理的反硝化速率均值分别为（172.8±19.8）、（216.0±45.7）μg·kg-·1h-1和（216.3±44.6）μg·kg-·1h-1。研究表明,模拟酸雨强度升高未显著影响冬小麦田土壤呼吸、硝化和反硝化作用;高强度模拟酸雨（pH=2.0）降低了大豆田土壤呼吸速率和CO2产生速率,但对土壤硝化和反硝化作用有促进作用。

英文摘要：

In order to investigate the effects of simulated acid rain on soil respiration,nitrification and denitrification in a cropland under winter wheat-soybean rotation,randomized block experiments were carried out in the cropland.4 blocks were arranged and there were 4 acid rain treatments,which were coded as A1（pH=6.7）,A2（pH=4.0）,A3（pH=3.0）and A4（pH=2.0） in each block.A portable soil CO2 fluxes system（LI-8100） was used to measure soil respiration rates.Soil CO2 production rates,nitrification and denitrification rates were determined by using a Barometric Process Separation（BaPS） method.Results indicated that there were no significant differences（P0.05） in soil respiration rates among different treatments in the wheat growth season,while intensive acid rain significantly（P0.05） inhibited soil respiration in the following soybean growth season.Given the winter wheat-soybean rotation season,simulated acid rain had no significant effects（P0.05） on soil respiration.Mean soil respiration rates during the rotation season were（2.26±0.11）,（2.31±0.20）,（1.91±0.09）,（2.03±0.17） μmol·m-2·s-1 for A1,A2,A3 and A4 treatments,respectively.All rates of soil CO2 production,nitrification and denitrification were not significantly（P0.05） different among the A1,A3 and A4 treatments during the winter wheat growth season.However,in the soybean growth season,intensive acid rain significantly（P0.05）inhibited soil CO2 production rates.Mean nitrification rates in the soybean planted cropland were（191.6±36.1）,（261.6±36.3） μg·kg-1·h-1 and（255.2±45.1） μg·kg-1·h-1 for the A1,A3 and A4 treatments,respectively,while mean denitrification rates were（172.8±19.8）,（216.0±45.7）μg·kg-1·h-1 and（216.3±44.6）μg·kg-1·h-1,for the 3 treatments,respectively.It could be concluded that simulated acid rain had no significantly effects on all of the rates of soil respiration,CO2 production,nitrification and denitrificantion in the winter wheat growth season.Durin