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以内蒙古河套灌区为研究对象,利用经典统计学与地统计学相结合的方法,对1、4、8 km 3个样点间距下不同土层(0~20、20~40、40~70与70~100 cm)有机质含量的空间变异及尺度效应进行分析。经典统计结果表明,不同尺度下有机质含量均值的变异程度均随着土层深度的增加而增加,其在0~20和20~40 cm土层随着尺度的增加而变大。地统计分析结果显示,不同尺度不同土层有机质含量均具有强烈的空间自相关,且其空间分布主导影响因子为土壤类型。各尺度不同土层有机质空间分布均存在一定程度的方向性,其在小尺度(1 km)表现为东西方向上的条状变异;在中尺度(4 km)及大尺度(8 km)均在土壤表层的东-西和西北-东南方向存在强烈的空间变异性。各尺度下有机质的普通克里格插值交叉验证的均方根误差均小于1,说明样本的空间变异均被高估。研究结果对于理解土壤有机质空间分布具有重要意义,为农业技术研究中野外采样系统设计提供一定的参考。
Taking Hetao Irrigation District of Inner Mongolia as the research object, by means of the combination of classical statistics and geo-statistics, the soil samples from different soil layers (0-20, 20-40, 40-70, 70 ~ 100 cm) spatial variability and scale effects of organic matter content were analyzed. The results of classical statistics show that the variation of mean value of organic matter content at different scales increases with the depth of soil, and increases with the increase of soil depth at 0 ~ 20 and 20 ~ 40 cm. Geostatistical analysis showed that there was a strong spatial autocorrelation of organic matter content in different soil layers at different scales, and the dominant factor of spatial distribution was soil type. The spatial distribution of organic matter in different soil layers at different scales has a certain degree of directivity, which shows a strip-shaped variation in the east-west direction at a small scale (1 km). In both the mesoscale (4 km) and large-scale (8 km) Soil surface east-west and northwest-southeast directions there is a strong spatial variability. The root-mean-square error of cross-validation of common kriging interpolation of organic matter under all scales was less than 1, indicating that the spatial variability of samples was over-estimated. The results are of great significance for understanding the spatial distribution of soil organic matter and provide some references for the design of field sampling system in agricultural technology research.