川西南山区耕地土壤速效钾空间特征及影响因素分析

Geostatistics and GIS Analysis of Soil Available Potassium in Mountainous Southwestern Sichuan

基于地统计学和GIS技术相结合的方法,研究了川西南山区耕地土壤速效钾的空间分布特征及其影响因素。结果表明,研究区耕地土壤速效钾含量变化范围为20-408 mg·kg^-1,属于轻度缺乏;变异系数为55.18%,属于中等变异。川西南山区耕地土壤速效钾变异函数的最佳模型为指数模型,其块金系数为46.6%,具有中等程度的空间相关性,其空间变异受地结构因素和随机因素共同导致,结构性因素起主导作用。速效钾含量空间变异所呈现出的斑块大小、斑块形状及空间分布等具有显著的区域差异,分布趋势与研究区地形分布规律较为一致。因而,川西南山区应结合当地不同土壤类型养分状况和不同海拔段的水热条件,合理施用钾肥。

Gcostatistical and GIS technology were utilized to study the cultivated soil potassium spatial distribution and influencing factors in the mountainous southwestern Sichuan. Results showed that the concentrations of soil available potassium ranged from 20 to 408 mg· kg^ -1 in the study area, and was mildly deficient; The variation coefficient was 55.18 %. The best fitting model of variogram was exponential model with the nugget/sill of soil available potassium in 46.6 % indicating medemte spatial correlation. The spatial variability of soil available potassium was co-affected by structural factors and random favors, and structural factors played a leading role. The spatial variation diagram of soil available potassium showed the plaque size, shape and spatial distribution of patches with significant regional differences. Topographic distribution was consistent with the distribution trend of patches in study area. Thus, the different county should apply the potassium reasonably based on the nutrient status of different soil types and hydrothennal conditions at different altitudes.