Chen Shu-tao, Zhu Da-wei, Niu Chuan-po, Zou Jian-wen, Wang Chao, Sun Wen-juan
School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China.
Huan Jing Ke Xue. 2009 Oct 15;30(10):2858-65.
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 0.0001.
为了研究诸如氮肥施用和耕作方式等管理措施对农田土壤呼吸的影响，采用静态不透明箱-气相色谱法原位测量土壤CO₂通量。田间测量在5个生长季进行，分别是2002 - 2003年小麦季、2003年玉米季和大豆季、2003 - 2004年小麦季、2004年玉米季以及2004 - 2005年小麦季。我们的结果表明，在2002年11月9日、2003年2月14日和3月26日进行3次施肥后，施肥处理的土壤呼吸相较于不施肥处理有所增加。且第三次施肥后增加最为明显。几种施肥处理之间的土壤呼吸未发现显著差异。耕作深度对土壤呼吸的影响取决于前茬作物种植方式。在2003 - 2004年小麦生长季（前茬作物为水稻田），免耕处理和浅耕处理之间的平均土壤呼吸速率无显著差异（p > 0.05）。在2004年玉米生长季，浅耕处理CT2相较于免耕处理NT2导致更高的土壤CO₂损失，然而，在随后的2004 - 2005年小麦生长季，免耕处理NT3的土壤呼吸速率显著更高（p < 0.05）。与免耕（NT4）相比，深耕（25厘米深度）在2004 - 2005年小麦生长季显著增加了土壤呼吸。回归分析表明，指数函数可用于拟合土壤呼吸与温度之间的关系。指数关系得出的Q10值在1.26至3.60之间，平均值为2.08。为评估温度对土壤呼吸的影响，对每个处理和每个作物生长季的CO₂排放通量进行了标准化。将标准化后的土壤呼吸与温度作图，这两个参数之间的指数关系变得明显。根据指数关系，温度系数Q10评估为1.66。进一步研究表明，通过一个考虑土壤温度和湿度对土壤呼吸影响的经验模型可以很好地模拟土壤呼吸。该模型描述了所测463个土壤呼吸速率的54%的变异，R²为0.54，p值小于0.0001。
