Study on the spatial pattern of available Potassium in county farmland | 县域耕地土壤速效磷空间格局研究

chinois. 研究陕西关中地区县域耕地土壤速效磷的空间变异特征和分布格局，探讨其主要影响因子。以陕西省武功县为研究区，在0～20 cm土层，以“S”形法采集耕地土样2 219个，运用地统计学结合GIS技术，拟合最优半方差模型，进行普通Kriging插值分析。研究区土壤速效磷含量为3.10~65.80 mg/kg，平均值为21.75 mg/kg，最佳半方差模型为球状模型，且具各向异性特征，块金系数为0.360 3，具有中等强度的空间相关性。研究区土壤速效磷含量高低区域分布比较明显，总体分布状况与地貌特征基本一致。地形地貌、土壤质地、灌溉条件和施肥是影响武功县耕地土壤速效磷含量空间格局的主要因素。

anglais. The study aimed to explore the spatial variability and pattern of soil available Potassium in county farmland,with which to analyze its spatial distribution and major influencing factors. This paper took the Wugong county of Shaanxi as the research site. Geostatistics combined with geographical information system (GIS) was applied to study the best semi-variance theory model and to analyze oridinary Kriging interpolation of available Potassium in soil based on the data of 2 219 soil samples taken by “S” shape methods in the 0-20 cm topsoil in farmland of study area. The available Potassium content ranged from 3.10 mg/kg to 65.80 mg/kg in the study area, with an average 21.75 mg/kg. The best theoretical model was spherical one, with an anisotropy. The ratio of nugget/sill of soil available Potassium was 0.360 3, and the spatial autocorrelation belonged to middle intensity. The distribution pattern of soil available Potassium was basically identical with terrain features. Spatial variation of soil available Potassium was mainly caused by topography and geomorphology, soil texture,fertilization, irrigation condition.