农田土壤速效钾含量的空间变异研究

论文以高产潮土区2007年104个土壤采样点耕层速效钾含量为基础，基于地统计学原理，结合GIS空间分析技术，探讨了土壤速效钾含量的空间变异特征，建立了土壤速效钾含量的空间变异模型，形成了土壤速效钾含量的空间分布图，阐明了影响高产农田土壤速效钾含量分布不均衡的原因。研究结果表明，高产潮土区土壤速效钾含量平均为287．476gkg^-1，最高为483．433gkg^-1，最低为119．435gkg^-1，球状模型是土壤速效钾连续性空间分布的最佳模型，其块金值，基台值为0．399，说明土壤速效钾在变程为57．691米的范围内具有中等强度的空间变异性，含量高低的区域分布比较明显，在地块东南部和中部为其含量较高的区域，含量较低的两个突出区域呈典型的圈层分布，由内向外含量递增，具有较强的渐变性分布规律。总的来看，土壤速效钾约有60．1％的空间变异来自于土壤母质、地形地貌、气候等非人为的结构性因素，39．9％的变异来自于随机性因素如施肥、灌溉、管理水平等因素的影响。

Spatial variability study of soil available potassium at the field scale

This paper took the high-yield wheat field of alluvial soil area as the research site, aimed to explore the spatial pattern of soil available Potassium. With the help of GPS, 104 observing points were made in a wheat field approximate 3hm2 on the north of Xiaoqinghe River in Shandong province in 2007. Geostatistics combined with geographical information system（GIS） were applied to reveal the spatial variability of soil available Potassium content in the topsoil （0-20cm）. The paper established the variability model of spatial distribution. Research results indicated the average content of soil available Potassium was 287.476gkg^-1, the high value was 483.433gkg^-1, the low value was 119.435gkg^-1. Field experiments and model prediction were employed in this paper, the range, nugget and sill were calculated, Semivariogram model of soil available Potassium was established, the interpolation methods were decided, the optimal interpolation by ordinary Kriging was selected, and the spatial distributing map of soil available Potassium was drawn. It is shown that the semivariogram structures of soil available Potassium was spherical, the ratio of nugget/sill of soil available Potassium was 0.399, and the variation belonged to middle intensity within 57.691 meters distance, there is high content of soil available Potassium in the southeast and middle of the field, there is the two area of the low content at the north of research site. Spatial variation of soil available potassium was mainly caused by structural factors （parent material, terrain,climate, water table etc.）, the structure variability of it took 60.1% of the total variability, 39.9% of the total variability were caused by random factors（fertilization, environmental pollution, cultivation measures, management etc.）.