长期耕作条件下小尺度农田土壤有机质空间变异性

Spatial variability of soil organic matter in long-term small scale across cultivated crop land

采用10 m×10 m高密度网格采样的地统计学方法,进行了小尺度（10.24 hm2）土壤耕层（0-30 cm）有机质的空间分布特征量化研究。研究发现,取样区内土壤有机质空间分布表现出弱变异性,CV≤1.84%,但整体含量偏低,SOM≤1.04%;东西、南北、东南和西南四个方向上半方差函数的差异性表明,有机质空间分布具有异向性,基于各向同性假设和各向异性的半方差函数结构分析以及Kriging估计都能很好地反映取样区土壤有机质的空间变异性,但后者在估计结果精度和真实性方面要优于前者。

The data collected from a 10.24 hm2 crop land in dense grid of 10 m×10 m were used to analyze the spatial variability of the surface（0～30 cm）soil organic matter（SOM）by geostatistics method.Within the study area,soil organic matter had weak variability as CV≤1.84%,but it was entirely low in the content no more than 1.04%.The differences between semivariograms among the four directions showed that soil organic matter had anistropical distribution characteristics.Both Kriging estimation based on the isotropical semivariogram model and the combination model of anisotropical semivariogram made satisfiable predication,however,the latter had better accuracy and reality than the anterior.