中文摘要：

土壤干湿交替对于土壤有机碳循环,土壤矿化作用和微生物生长代谢有重要影响。文章以表层土（0~20 cm）为受试土壤,通过室内孵育试验,模拟自然的干湿交替循环,同时设置恒定含水量的对照试验,重点研究了缓慢干旱和快速复水的处理方式对土壤有机碳变化趋势的影响机理。结果表明：与恒定含水量的对照组相比,多重干湿交替处理能够显著提高土壤的矿化作用,土壤中的微生物在复水后的24 h内迅速增加,4个干湿周期使得总的微生物生物量碳平均增加了50%左右。土壤中部分溶解性有机碳在复水后被微生物利用,降低幅度为10%~20%。但是在没有外源碳供给的情况下,4个干湿交替使得土壤总有机碳较原始水平降低了21%。

英文摘要：

An indoor incubation experiment was carried out with the top soil of depth 0~20 cm being treated by means of simulated natural drying/wetting cycles. The results suggested that in contrast with the control group,multiple drying/wetting cycles could intensify the decomposing process of organic matter in soil,e.g.,after rewetting microbial biomass increased quickly within 24 h;and four rounds of drying/wetting resulted in the increase of microbial biomass carbon by about 50%.Owing to the utilization of part of the dissolved carbon by microbe after rewetting,dissolved carbon decreased ranging from10%~20%;and without any supplement of carbon,total organic carbon dropped by 21% from the initial level after four rounds of drying and wetting.