中文摘要：

通过室内模拟降雨一维垂直土柱入渗实验,在非灭菌与灭菌条件下,连续地监测土壤不同深度处CO2浓度以及土壤含水率。采用闭合循环回路测量系统,结合膜管（METT）技术来对降雨条件下土壤不同深度处CO2浓度进行监测,研究CO2的短时排放特性。结果表明,在时间上土壤不同深度处含水率与CO2浓度变化并未呈现出一致的趋势。对干土加水时,土壤CO2浓度的迅速增加除了受到微生物矿化作用之外,气体对流、扩散等物理过程也影响较大。对于灭菌土壤,CO2在土壤中的运移只是一个较短的动力学过程,故其变化较快;而对于非灭菌土壤,由于微生物对土壤中有机质的矿化作用,所以CO2浓度较高但变化相对较缓。

英文摘要：

To better understand soil CO2 release processes during drying and wetting, infiltration experimetnts were conducted in soil columns. Air-dried sterile and non-sterile soils were filled into two one-dimensional soil columns, respectively. At the beginning of experiments, a simulated rainfall （with the amount of 3 cm within 1 h ）was added to each of the soil columns. Soil water contents at depths of 5, 10, and 20 cm were continuously measured with time domain reflectometry（TDR ）during the experiment. Concentrations of CO2 at the 3 depths were simuhaneously measured using the closed loop gas circulating system and membrane tubing technique over the experimental period. Results showed that the changes of soil water content were not consistent with those of soil CO2 concentrations at any of the three depths in both soils. The 3 cm simulated rainfall induced a pattern of soil water content pulse at depths of 5 and 10 cm in both the sterile and non-sterile soil columns. The wetting process resulted in a rapid increase of CO2 concentrations at all the three depths in a relatively short period after adding water in both soils. However. CO2 concentrations at the three depths in the sterile soil were lower than those in the non-sterile soil. The concentrations of CO2, at the depths decreased much more slowly in the non-sterile soil than in the sterile soil. The results indicated that besides the microbial mineralization, physical processes, such as gas convection and diffnsion, had a significant impact on the pulse of CO2 released from soil and the rapid increase of soil CO2 concentration, The change of CO2 concentration in the sterile soil column was a result of a temporal dynamic process. The CO2 concentration in the non-sterile soil was higher but decreased with time much more slowly than that in the sterile soil, attributable to microbial mineralization of soil organic matter.