| 管理措施对农田生态系统土壤呼吸的影响 |
| 摘要点击 2938 全文点击 1538 投稿时间：2008-11-29 修订日期：2009-02-28 |
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| 中文关键词 管理措施 农田 土壤呼吸 土壤温度 土壤湿度 |
| 英文关键词 management regime farmland soil respiration soil temperature soil moisture |
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| 中文摘要 |
| 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）. |
| 英文摘要 |
| In order to examine the effects of management regime, such as nitrogen application and plowing method, on soil respiration from farmland, the static opaque chamber-gas chromatograph method was used to measure soil CO2 fluxes in situ. The field measurement was carried out for 5 growing seasons, which were the 2002-2003 wheat, 2003 maize and soybean, 2003-2004 wheat, 2004 maize and 2004-2005 wheat seasons. Our results showed that soil respiration increased in fertilizer-applied treatments compared with no fertilizer treatment after 3 times of fertilizer application on 9 November 2002, 14 February and 26 March 2003. And the most obvious increase appeared following the third fertilizer application. No significant difference in soil respiration was found among several fertilizer application treatments. The effect of plowing depth on soil respiration was contingent on preceding cropping practice. Over the 2003-2004 wheat-growing seasons (its preceding cropping practice was rice paddy), mean soil respiration rates were not significant different (p>0.05) between no plowing treatment and shallow plowing treatment. The shallow plowing treatment CT2 led to higher soil CO2 losses compared with no plowing treatment of NT2 in the 2004 maize-growing season, however, the significant higher (p<0.05) soil respiration rates occurred with no plowing treatment of NT3 in the following 2004-2005 wheat-growing season. Intensive plowing (25 cm depth), compared with no plowing practice (NT4), increased soil respiration significantly during the 2004-2005 wheat_growing season. Regression analysis showed that the exponential function could be employed to fit the relationship between soil respiration and temperature. The exponential relationship yielded the Q10 values which were varied from 1.26 to 3.60, with a mean value of 2.08. To evaluate the effect of temperature on soil respiration, the CO2 emission fluxes were normalized for each treatment and each crop growing season. Plotting the normalized soil respiration against the temperature, the exponential relationship between these two parameters becomes obvious. The temperature coefficient Q10 was then evaluated as 1.66 according to the exponential relationship. Further investigation indicated that soil respiration could be well simulated by an empirical model in which the effects of both soil temperature and moisture on soil respiration were considered. This model described 54% variances of the measured 463 soil respiration rates, with a R2 of 0.54 and a p value less than 0.000 1. |
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