土壤水分对水稻土和菜园土有机碳分解的影响

采用培养法研究在不同水分条件下水稻土和菜园土有机碳的分解变化特征。结果表明,不同的土壤类型和不同的水分条件下CO2释放速率的变化趋势都是前期分解速率快,后期分解速率减慢并趋于稳定。低土壤水分含量不利于水稻土和菜园土的有机碳分解,中等土壤水分含量有利于菜园土的有机碳分解,高土壤水分含量有利于水稻土的有机碳分解。对有机碳分解累计量曲线的拟合,幂函数(y=b0*xb1)可以很好的反映这种变化趋势,并且b0和b1与土壤水分含量都有很好的相关性。

Effects of Water Content on Decomposition of Soil Organic Carbon

The paddy soil and vegetable garden soil were adjusted into 5 gradients of water contents:20%~100% and incubated at 25℃ for 100d. Results showed that the decomposition rates of soil organic carbon in cropland at the 5 gradients of water contents increased significantly in the beginning,then kept at steady and lower levels throughout the 100d incubation period. Low-water content was not beneficial to soil organic carbon decomposition of paddy soil and vegetable garden soil,medium-water content was good for decomposing soil organic carbon of vegetable garden soil,high-water content benefited the one of paddy soil. The power function was fit for the curve of soil organic carbon cumulative amount,and there was a better correlation between b0,b1 and water content,respectively.