西南丘陵区水田土壤有效铜和有效锌含量的空间变异

Spatial Variability's Properties of Available Cu and Available Zn on Paddy Soil in Hill of Southwest

应用地统计学和GIS空间分析技术,对丘陵山区水田土壤有效铜和有效锌进行了空间变异特征和空间插值质量研究。研究区有效铜、锌均表现为中等空间变异性,其变异系数的大小为有效铜>有效锌。各向同性下,有效铜和有效的空间变异均存在着良好的半方差结构,其含量的空间自相关距离均大于采样间距,表明研究区土壤养分在区域范围内均存在着空间相关性,块金系数介于25%～50%,说明土壤有效铜和有效锌均具有明显的空间自相关性,其空间变异主要是由结构性和随机性因素共同作用的结果。各向异性结构明显,有效铜在西北-东南方向上的空间变异最大,有效锌在东北-西南方向上空间变异最小。水田土壤有效铜含量丰富,大于1.8 mg.kg-1的水田面积约占所有水田面积的83.3%;土壤有效锌含量,主要分布在1.0～2.0 mg.kg-1之间,约占所有水田面积的79.6%。

The spatial variability＇ s properties of available Cu and available Zn of paddy soil in hill of southwest China were analyzed using the methods of Geostatistics, and GIS technique. The available Cu and available Zn of soil had a medium spatial variability, and the variation coefficients was expressed as the available Cu 〉 the available Zn. According to the isotropy, semi-varlance structures for spatial variability of the available Cu and available Zn existed, and the limit distance of spatial correlation was relatively large. In the researched areas, the spa- tial correlation of the available Cu and available Zn existed in area coverage and the nugget value was from 25 % - 50 %. Spatial variability was caused by structure and random factors. The structure of anisotropy was obvious. The available Cu was strong mostly at the northwest- southeast direction, available Zn was variable weakly at the northeast-southwest direction. The available Cu was rich in paddy soil, and the area of paddy with available Cu over 1.8 mg·kg^-1 was 83.3 %. The concentration of the available Zn in paddy soil was between 1.0 and 2.0 mg·kg^-1, of which proportion of paddy was 79.6 %.