苏北县域农田土壤有机碳研究

Study on Farmland Soil Organic Carbon at County Scale in Northern Jiangsu

农田SOC与土壤肥力、粮食安全以及全球气候变化关系密切。本文以江苏省丰县农田土壤为研究对象,通过野外取样及室内分析,对不同种植作物类型下SOC及其组分进行对比分析。结果表明:1) 不同种植作物类型之间SOC、HC含量排序为:大豆 > 牛蒡 > 山药 > 棉花 > 玉米;不同种植作物类型下不同土层比较得出,牛蒡、山药最下层(50~100 cm) SOC及HC含量要高于其他3种作物类型。2) 牛蒡、山药WSOC和ROC含量较高,棉花、大豆、玉米相对较低,并且牛蒡、山药WSOC含量的下降幅度较小;不同种植作物类型下MBC含量排序为:山药 > 棉花 > 牛蒡 > 玉米 > 大豆,其中大豆不同土层之间的MBC含量下降幅度不明显。该研究结果对于明确当地农田SOC的稳定性以及固碳机制具有一定指导意义。

The organic carbon (SOC) of farmland is closely related to soil fertility, food security, and global climate change. Taking the farmland soil in Fengxian County, Jiangsu Province as the research object, this paper makes a comparative analysis of SOC and its components under different crop types on the basis of field sampling and laboratory analysis of soil samples. The results showed that: 1) The order of SOC and humus carbon (HC) contents among different crop types was soybean > burdock > yam > cotton > corn. Compared with different soil layers under different crop types, the contents of SOC and HC in the lowest layer (50~100 cm) of burdock and yam are higher than those of the other three crop types. 2) The contents of water-soluble organic carbon (WSOC) and soil oxidizable organic carbon (ROC) in burdock and yam were higher, while those in cotton, soybean, and corn were relatively lower, and the decrease of WSOC in burdock and yam was small;The order of microbial biomass organic carbon (MBC) content under different planting crop types is: Yam > cotton > burdock > corn > soybean. The decline of MBC content in different soil layers of soybean is not obvious. The research results have certain guiding significance for clarifying the stability of SOC and the carbon sequestration mechanism of local farmland.