水分状况对水稻土有机碳矿化动态的影响

Effect of Moisture Regime on Dynamics of Soil Organic Carbon Mineralization

水分状况影响土壤水溶性有机C(DOC)溶出,而DOC含量变化与土壤有机C矿化动态有密切关系。通过室内试验,研究了不同水土比提取条件对太湖地区水稻土(黄泥土)DOC含量的影响,观测了培育过程中土壤DOC含量及土壤有机C矿化的动态变化。结果表明,土壤DOC含量随着水土比的增大而升高,且两者之间呈显著的线性关系。长期室内恒温培育条件下,淹水处理土壤DOC含量显著高于好气处理(P<0.01),且在整个培养期内都保持这一趋势,而两处理之间的差值则表现为先增大后减小。培育过程中,土壤日均矿化量好气处理高于淹水处理,但两处理之间的差值则随着培养时间延长而不断缩小。

Soil moisture influences release of soil dissolved organic carbon （DOC）, which is related closely to mineralization of soil organic carbon. By lab incubation experiment, dynamics of DOC contents under different water/soil ratios and mineralization of soil organic carbon under different moisture regimes during the incubation period were observed to analyze relationship between DOC content and soil organic carbon mineralization. Results indicated a significantly positive linear relationship between DOC content and water-soil ratio; DOC concentration under submergence treatment was significantly higher than that under aerobic treatment （P〈0.01） during whole incubation period, and difference increased at beginning but then decreased with incubation time; Daily mineralization under aerobic condition was higher than that under submergence, but difference deceased gradually with incubation time.