保护性耕作对南方稻麦两熟高产农田土壤碳库特性的影响

Effects of Conservation Tillage on Soil Carbon Pool from High Production Rice-wheat Double Cropping Systems in South China

在江苏省苏州市稻麦两熟高产农田进行了5年的田间定位试验,分析了保护性耕作对土壤不同层次总有机碳、活性有机碳含量的短期影响,计算了各处理的土壤碳库管理指数。结果表明：与常规耕作相比,少免耕、常规耕作＋秸秆还田、少免耕＋秸秆还田处理显著提高0~5、5~10 cm土层土壤总有机碳、活性有机碳含量及土壤碳库管理指数,常规耕作＋秸秆还田处理还有利于提高10~20 cm土层土壤总有机碳、活性有机碳含量及土壤碳库管理指数,但保护性耕作对20~30 cm土层土壤碳库特性无显著影响。相关分析显示,短期内少免耕主要是通过增加土壤总有机碳含量提高土壤碳库管理指数,而常规耕作＋秸秆还田、少免耕＋秸秆还田主要是通过增加土壤总有机碳含量以及改善土壤有机碳活度来增加土壤碳库管理指数。

A 5-year field experiment was conducted in Suzhou, Jiangsu province to study the effects of conservation tillage on soil total organic carbon （TOC）, labile organic carbon （LOC） and carbon pool management index （CPMI） in order to assess soll quality under a high pro- duction rice-wheat double cropping system. The reduced and no-tillage （RNT）, conventional tillage with straw incorporation （CTS）, re- duced and no-tillage with straw incorporation （RN＇IS） and conventional tillage （CT） treatments were sot up. The results showed that the TOC and LOC contents and CPMI at the soil depths of 0 - 5, 5 - 10 cm under RNT, CTS, RNTS were significantly higher than that under CT. The TOC, LOC contents and CPMI in 10 -20 cm soil layers under CTS were significantly increased as compared to CT. No significant difference among different tillage practices were found on soil carbon pool in 20 - 30 cm soil layer in this study. Correlation analysis revealed a significant correlation of CPMI with TOC in RNT, moreover, the significant correlations of CPMI with TOC and LOC were also observed in CTS and RNTS.