济宁南部区域耕作层土壤有机碳密度及储量研究

济宁市南部区域是著名的国家商品粮、优质大蒜、优质稻米和有机蔬菜生产基地,由于土壤有机碳作为农田生态系统中土壤肥力的重要组成成分之一,在土壤改良、作物质量和产量提高等方面都有十分重要的作用,因此,对济宁南部区域耕作层土壤有机碳密度及储量的研究具有十分重要的意义。本文以济宁南部煤田地区作为典型区域,以耕作层土壤(0~20cm)为研究对象,采集了79件耕作层土壤样品,利用元素分析仪测定了土壤样品中有机碳含量。经统计分析发现,各类型土壤有机碳密度介于1.92~4.83kg/m2之间,有机碳密度的加权平均值为4.03kg/m2,高于中国表层土壤有机碳密度的平均值2.97kg/m2;通过壤质类型分类而估算的有机碳总储量为4.57×109 kg,通过土壤利用方式分类而估算的有机碳总储量为4.53×109 kg,二者基本吻合;济宁南部区域耕作层土壤有机碳富集程度受人类活动影响较大,耕作层土壤中氮含量与有机碳的线性相关系数为0.924 9;另外,有机碳富集程度与秸秆返田规模也有着一定的关联。研究结果不仅为研究区今后开展耕作层土壤环境质量评价提供依据,也为区域生态平衡研究奠定了基础。

Organic Carbon Density and Reserve of Plowing Layer Soil from Southern Ji'ning District, Shandong Province, China

Southern Ji''ning district, Shandong Province, China is famous as production bases for national commodity grain, high quality garlic, high quality rice and organic vegetables. As one of the most important parts of soil fertility in farmland ecosystem, organic carbon plays an important role in improving soil quality and raising yield of crops. Therefore, it''s of great significance to study the density and reserve of organic carbon in plowing layer soil. Herein, 79 samples of plowing soil in southern Ji''ning district were collected and their organic carbon contents were measured using element analyzer. According to the result, the densities of organic carbon were between 1.92 and 4.83 kg/m², and the weighted average was 4.03 kg/m², higher than the average of Chinese plowing layer soil value (2.97 kg/m²). The total reserve of organic carbon estimated by using soil type category was 4.57×10⁹ kg, while the total reserve was 4.53×10⁹ kg estimated by using soil utilization type. The organic carbon accumulation level in plowing layer soil of southern Ji''ning district was significantly impacted by human activity. The linear dependent coefficient between nitrogen content and organic carbon in plowing layer soil was 0.9249. Furthermore, accumulation level of organic carbon was also related to the scale of the straw that was returned back to soil. The result could not only provide support for further soil environmental quality assessment but also lay foundation for research on regional ecological balance.