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为研究管理措施(氮肥施用和耕翻措施)对农田土壤呼吸的影响,采用静态暗箱-气相色谱法对农田生态系统的土壤呼吸作用进行了5个生长季(2002~2003年小麦,2003年玉米、大豆,2003~2004年小麦,2004年玉米,2004~2005年小麦)的野外观测试验.结果表明,冬小麦基肥(2002-11-09)、返青肥(2003-02-14)和拔节肥(2003-03-26)施用后2周内氮肥施用处理的土壤呼吸速率明显高于对照,但不同施氮水平间的土壤呼吸速率无显著差异.耕翻对土壤呼吸的影响效应受到前茬作物类型的制约.在2003~2004年的冬小麦生长季(其前茬种植的作物为水稻),不耕和浅耕处理的平均土壤呼吸速率之间无显著差异(p>0.05).在2004年玉米生长季浅耕比不耕处理显著增加了土壤呼吸速率(p<0.05),而在后茬的2004~2005年小麦生长季浅耕比不耕又显著降低了土壤呼吸速率(p<0.05).在前茬作物为水稻的麦田(2004~2005年小麦生长季),深耕比不耕处理显著增加了土壤CO2排放量.不同管理措施下,农田土壤呼吸与土壤温度的关系均可用指数方程描述,针对不同管理措施下拟合得到的指数方程求得的Q10值在1.26~3.60之间变异,其均值为2.08.而将所有管理措施下的标准化土壤呼吸速率与土壤温度进行拟合也可发现二者间存在指数关系,此时求得的Q10为1.66.根据土壤温度和湿度对土壤呼吸的影响规律,建立的温度影响函数(指数函数)和湿度影响函数(二次函数)耦合的模拟模型可解释54%的土壤呼吸变异(R2=0.54,n=463,p<0.000 1).
In order to study the effects of management measures (nitrogen application and tillage) on soil respiration in farmland, static black box-gas chromatography (GC-MS) was used to study soil respiration of farmland ecosystem for five growing seasons (2002-2003, 2003 maize , Soybean, 2003-2004 wheat, 2004 maize, 2004-2005 wheat), the results showed that winter wheat basal fertilizer (2002-11-09), greening fertilizer (2003-02-14) and jointing fertilizer 2003-03-26) The soil respiration rate of nitrogen application two weeks after application was significantly higher than that of the control, but there was no significant difference of soil respiration rate between different nitrogen application levels.The effect of plowing on soil respiration was affected by the type of the previous crop .In the winter wheat growing season from 2003 to 2004, the crop of the former crop was rice, there was no significant difference (p> 0.05) between the average soil respiration rate of non-tillage and shallow tillage treatments Compared with no tillage, the soil respiration rate increased significantly (p <0.05) in the seasons with the shallow tillage and the shallow tillage with no tillage in 2004-2005 significantly reduced the soil respiration rate (p <0.05). The former crop is a paddy field of wheat (2004-2005 wheat growing season), deep plowing The soil non-tillage treatment significantly increased the soil CO2 emissions.Under different management measures, the relationship between soil respiration and soil temperature in farmland can be described by exponential equation, and the Q10 values obtained from the exponential equation fitted under different management measures ranged from 1.26 to 3.60 , With a mean value of 2.08, and the standardized soil respiration rate under all management measures fitted with the soil temperature can also be found exponential relationship between the two, the Q10 obtained at this time was 1.66.According to soil temperature and humidity The model of the influence of soil respiration, the establishment of a temperature-dependent function (exponential function) and the humidity-dependent function (quadratic function) can account for 54% of the soil respiration variability (R2 = 0.54, n = 463, p <0.0001 ).