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在河南省驻马店市西平县砂姜黑土(砂姜潮湿雏形土)区,采用0.5 km×0.5 km网格法采集248个土壤耕作层样本,其中124个作为估值数据集,124个作为验证数据集,设计了3种不同采样尺度的估值数据集抽样方案,对比了土壤图法和Kriging法对土壤有机质、全氮、全磷、缓效钾和速效钾的估值效果。结果表明土壤图法对土种内变异系数较小,但土种之间差异较大的全磷、全氮和有机质的估值精度仅稍低于Kriging方法,在空间变异格局表达方面的功能也大致相同。对土种内变异系数较大,但空间变异结构性明显的速效钾,Kriging估值效果显著优于土壤图法。降低采样密度使Kriging估值平滑效应增加,估值精度降低,且集中出现在那些内部变异系数较大的土种内。该结论揭示在土壤调查的初级阶段采集少量的样点对土种内的土壤变量的变异程度做出估计对进一步的采样方案设计和土壤估值方法选择有指导意义。
A total of 248 soil tillage samples were collected using grid method of 0.5 km × 0.5 km in Xiping County of Xiping County, Zhumadian City, Henan Province, of which 124 were used as valuation data sets and 124 were used as validation data Set up three kinds of sample data sampling sets of different sampling scales, compared the soil map method and Kriging method of soil organic matter, total nitrogen, total phosphorus, slowly available potassium and available potassium valuation. The results showed that the soil map method had a smaller coefficient of variation in soil species, but the estimation accuracy of total phosphorus, total nitrogen and organic matter with large difference between soil types was only slightly lower than that of Kriging method. The function in the spatial variation pattern expression Roughly the same. Kriging estimation results are significantly better than soil mapping for available potassium with larger variation coefficient in soil species but obvious structural variation of spatial variability. Decreasing the sampling density increases Kriging’s estimation smoothing effect and the estimation accuracy decreases, and it is concentrated in those soil species with larger internal variation coefficient. This conclusion reveals that estimating the degree of variability of soil variables in soil samples by collecting a small number of samples during the initial stage of soil survey is instructive for further sampling scheme design and selection of soil estimation methods.