热带低丘地区农场尺度土壤质量指标的空间变异

Farm Scale Spatial Variability of Soil Quality Indicators

本文以我国热带地区海南儋州一个典型农场为样区,采用地统计学方法研究土壤质量指标的空间变异。研究选择了土壤质量评价最小数据集中的7项土壤质量指标(总有机碳,容重,粘粒含量,速效P、K,阳离子交换量,pH)进行分析,统计分析的结果表明,研究区域土壤存在酸化和养分贫瘠化现象。地统计学分析结果表明,表层土壤基底值普遍高于表下层土壤,说明表层土壤由于受随机因素影响更为强烈导致空间变异性增强。在各项土壤质量指标中,pH和土壤容重主要表现为基底效应,总有机碳、阳离子交换量,速效P、K含量以及亚表层土壤粘粒含量表现出中等空间相关性,表层粘粒含量空间变异随距离增加而增加。在GIS支持下,采用块段克立格方法(blockkriging)进行各项土壤质量指标的空间内插得到指标的等级分布图。研究结果可以为进一步的土壤质量综合评价提供方法和理论依据。

This research was conducted on a tropical farm in Danzhou, Hainan. Geostatistic methods were used to study the spatial variability of seven soil quality indicators in MDS (Minimum Data Set) for soil quality evaluation. The result showed that for all indicators, the surface Nugget value was higher than that of subsurface,for the surface soil was disturbed by random factors. Among the seven indicators, pH and bulk density showed a random variability for they had very high ratio of Nugget over Sill.Total soil organic matter, cation exchange capacity, Bray-P, exchangeable K and subsurface soil clay content showed a medium ratio of Nugget to Sill. A classified indicator map was produced with block kriging interpolation method and meanwhile the estimation error of such operation was given in a map.