苏北县域农田土壤碳库的剖面变化特征分析

Study on Profile Change Characteristics of Farmland Soil Carbon Pool in Northern Jiangsu

摘要: 农田土壤碳库质量水平是全球气候变化及其生态系统碳循环研究的核心内容。以江苏省丰县农田土壤为研究对象，通过野外调查和取样分析，系统研究不同种植农作物SOC、ASOC剖面变化特征以及CPMI评价分析。结果表明：1) 不同种植农作物类型SOC表聚现象显著，SOC、ASOC含量均随着土层的加深表现为下降趋势，且SOC含量下降幅度明显大于ASOC。2) 不同种植农作物类型下ASOC平均含量(0100 cm)排序为大豆 > 山药 > 牛蒡 > 棉花 > 玉米 > 裸地，作物类型影响着凋落层厚度及其微生物活性，通过农田水热因子的变化影响ASOC的分解和转化。3) 不同种植农作物类型CPMI (%)大小排序：大豆 > 山药 > 牛蒡 > 棉花 > 玉米 > 裸地，相对于裸地，地上农作物类型均有较强的固碳潜力，作物类型可以不同程度地提高农田土壤碳库质量。

Abstract: The soil carbon pool quality of farmland is the core content of global climate change and ecosystem carbon cycle research. Taking farmland soil in Fengxian County, Jiangsu Province as the object, through field investigation and sampling analysis, the change characteristics of SOC and ASOC profiles of different cultivated crops and CPMI evaluation analysis were systematically studied. The results showed that: 1) SOC surface accumulation was obvious in all crop types. With the increase of soil depth, SOC content and ASOC content showed a downward trend, and the decline of SOC content was significantly greater than that of ASOC. 2) The average content of ASOC (0~100 cm) under different crop types is soybean > yam > burdock > cotton > corn > bare land. Crop types affect the thickness of litter layer and soil microbial activity, and affect the decomposition and transformation of ASOC through the changes of ecological factors such as farmland temperature and water. 3) The order of CPMI (%) of different crop types: soybean > yam > burdock > cotton > corn > bare land. Different crop types have strong carbon sequestration potential, which can promote the improvement of farmland soil carbon pool quality to varying degrees.