秸秆覆盖深松对夏玉米田土壤有机碳库的影响

为探究秸秆覆盖深松对土壤有机碳库的影响,采用4种耕作模式处理（深松覆盖、深松不盖、免耕覆盖、免耕不盖）在河南西平进行了连续3年田间试验,研究了不同处理对土壤中有机碳（SOC）、易氧化有机碳（ROC）和溶解性有机碳（DOC）含量的影响。结果表明,4种耕作模式下,SOC、ROC和DOC含量均随着土层的加深而降低;在0~5cm和5~10cm土层,秸秆覆盖处理下SOC、ROC和DOC含量高于不覆盖处理,表现为深松覆盖>免耕覆盖>深松不盖>免耕不盖;而从10~20cm土层以下,免耕处理下SOC、ROC和DOC含量急剧下降,表现为深松覆盖>深松不盖>免耕覆盖>免耕不盖。相关性分析表明,ROC、DOC含量与SOC含量之间分别存在显著和极显著的相关关系,说明土壤ROC和DOC的含量很大程度上与SOC的储量相关。

Effects of Straw Mulching and Subsoiling on Soil Organic Carbon Pool in Summer Maize Field

In order to study the effects of straw mulching and subsoiling on soil organic carbon matter in summer maize field. Four tillage patterns were adopted in Xiping county, Henan province for three years. Four tillage patterns were subsoiling and mulching, subsoiling and no mulching, no tillage and mulching, no tillage and no mulching. Effects of different treatments on the contents of soil organic carbon (SOC), readily oxidizable carbon (ROC), and dissolved organic carbon (DOC) were analyzed. Results showed that the contents of SOC, ROC and DOC under different treatment appeared a declining trend with soil depth. The contents of SOC, ROC and DOC were higher in straw mulching than in no straw mulching, subsoiling and mulching > no tillage and mulching > subsoiling and no mulching > no tillage and no mulching. Below the 10-20cm soil layer, the contents of SOC, ROC and DOC were dropped sharply in the no tillage treatments, subsoiling and mulching > subsoiling and no mulching > no tillage and mulching > no tillage and no mulching. Correlation analysis showed that the contents of ROC and DOC were significant or extremely significant correlation to SOC content, respectively. It showed the ROC and DOC contents in soil were significantly correlated with the SOC content.