微山县农田耕层土壤有机碳空间变异及动态变化分析

Spatial Variability and Dynamic Change of Cropland Furrow Soil Organic Carbon in Weishan County

为研究微山县农田耕层土壤有机碳(SOC)空间变异规律和动态变化情况,基于地统计学和GIS对2009年SOC进行空间变异性分析,采用克里格插值分析SOC空间分布格局及其影响因素,然后与第二次土壤普查数据对比研究不同时间断面下SOC的动态变化特征。结果表明:微山县耕层SOC最佳拟合模型为指数模型,空间自相关距离为4500 m。从空间分布格局上看,SOC分布呈明显的块状,有机碳含量中部较高,南部和北部较低。从第二次土壤普查到2009年近30年间,SOC的平均值有明显的增加,由5.345 g/kg上升到8.558 g/kg,增幅为60.11%。不同土壤类型下,增幅不同,其中棕壤增幅最大,为187.03%,增幅最小的为砂姜黑土,为41.64%。不同土地利用类型下,水田类型下土壤有机碳增幅最小,为56.84%,旱地类型下,土壤有机碳增幅最大,为87.75%。研究结果为该区耕地质量的提高、农田生态系统的碳循环和农业的可持续发展提供可靠依据。

In order to study the law of spatial variability and dynamic change of the cropland furrow soil organic carbon （SOC）in Weishan County, the spatial variability of SOC in 2009 was analyzed based on geostatistics and GIS, and spatial distribution pattern and influencing factors of SOC were analyzed by using Kriging, and then the dynamic change characters of SOC were studied under different time sections by comparing the result with the datum of the second soil survey. The result showed that the best fitted semivariogram model of SOC in Wenshan was exponential model and the spatial autocorrelation distance was 4500 m. Judging from the spatial distribution pattern, the distributions of SOC showed obvious block characteristics, the content of SOC was found higher in the middle of the area, while lower in the south and north. In nearly 30 years from the second soil survey to 2009, there was an obvious increase of SOC average which rose from 5.345 g/kg to 8.558 g/kg and the rate of increase was 60.11%. Under different soil types, the rates of increase were different. Brown soil had the biggest rate of increase which was 187.03%, while mortar black soil had the smallest rate of increases which was 41.64% respectively. Under different land use types,paddy field had the smallest SOC increase which was 56.84%, while dry field had the largest SOC increase which was 87.75%. This study could provide a reliable basis for the improvement of cultivated land quality, carbon cycles of farmland ecosystem and sustainable agriculture development in this area.