江西省不同地貌单元耕地土壤有机碳空间变异的尺度效应

运用地统计学、地理信息系统、方差分析和回归分析相结合的方法，研究江西省不同地貌单元耕地土壤有机碳空间变异的尺度效应，尺度分为省域尺度、完整地貌单元尺度和完整地貌单元相对应的县域尺度。结果表明：(1)不同尺度下耕地土壤有机碳均值差异显著，变异系数基本不变；(2)从县域尺度到地貌单元尺度再到省域尺度，块金效应值和空间自相关距离呈增大趋势；(3)不同尺度土壤有机碳空间分布级别和面积比例差异明显，小尺度插值图信息更丰富；(4)方差分析和回归分析结果表明秸秆还田、成土母质、土壤类型、高程和土壤侵蚀对土壤有机碳空间变异存在显著影响，但不同尺度下影响程度有所差异。秸秆还田和土壤类型对土壤有机碳空间变异的影响不存在尺度效应，成土母质、高程和土壤侵蚀对其影响存在尺度效应。结果可为详细地理解不同尺度下土壤有机碳空间变异及估测土壤有机碳密度提供一定的参考依据。

Scaling Effect on Spatial Variation of Farmland Soil Organic Carbon in Different Geomorphic Units in Jiangxi Province

To study the scaling effect on spatial variation of farmland soil organic carbon in different geomorphic units in Jiangxi Province, using a combined method of classical statistics, geostatistics and a geographic information system, the scale was divided into geomorphic units, county scale corresponding to different geomorphic units and provincial scale. Results show as follows: ① The means of soil organic carbon in farmland was significantly different at different scales but the coefficient of variation was basically unchanged. ② From the county scale to the geomorphic unit, and to the provincial scale, the nugget/sill ratio and range are increasing. ③The spatial distribution level and proportion of soil organic carbon in different scales were significantly different and the spatial distribution in small scale was more abundant. ④Analysis of variance and regression analysis results showed that straw incorporation, parent material, soil type, elevation and soil erosion had a significant influence on the spatial variation of soil organic carbon, but the level between different scale influence degree. Straw incorporation and soil type have not scale effect on the spatial variation of soil organic carbon but parent material, elevation and soil erosion have. The results can provide some reference for understanding the spatial variation of soil organic carbon and estimating the density of soil organic carbon in different scales.