基于GIS的环巢湖地区土壤养分空间变异特征研究

Spatial variation of soil nutrient characteristics around Chaohu Lake based on GIS results

为探究环巢湖地区土壤养分的空间自相关性及其变异规律,在研究区域共采集8073个土壤样品,基于GIS技术并使用地统计方法和Moran′s I指数法对土壤pH、有机质、全氮、碱解氮、有效磷、速效钾和缓效钾进行了系统分析。结果表明:土壤pH、有机质、全氮、碱解氮、有效磷、速效钾和缓效钾的均值分别为6.07、19.97 g·kg^(-1)、1.16 g·kg^(-1)、112.95 mg·kg^(-1)、18.21 mg·kg^(-1)、130.88 mg·kg^(-1)和378.58 mg·kg^(-1),除有效磷为强变异外,其他养分均为中等程度变异;pH、全氮、有效磷、速效钾和缓效钾半变异函数最佳拟合模型为指数模型,有机质和碱解氮为高斯模型;pH和速效钾为中等空间自相关性,其他养分空间自相关性均较弱,表明养分空间变异主要受人为活动等随机性因素影响;各养分均为极显著空间正相关,其空间相关性大小依次为有效磷>速效钾>pH>缓效钾>全氮>有机质>碱解氮,且有效磷的空间自相关性显著大于其他养分。总体上看,环巢湖地区养分分布较为分散,南北方向有逐渐上升或下降的趋势,且养分高低值聚集区域也有明显的南北分布。

To explore the spatial autocorrelation and variation of soil nutrients around Chaohu Lake,a total of 8073 soil samples were collected in the study area.Soil pH,organic matter,total nitrogen,alkali-hydrolyzable nitrogen,olsen phosphorus,available potassium,and slowly released potassium were systematically analyzed using GIS technology,geostatistics,and Moran′s I index.The results indicated that the average values of soil pH,organic matter,total nitrogen,alkali-hydrolyzable nitrogen,olsen phosphorus,available potassium,and slowly released potassium were 6.07,19.97 g·kg^(-1),1.16 g·kg^(-1),112.95 mg·kg^(-1),18.21 mg·kg^(-1),130.88 mg·kg^(-1) and 378.58 mg·kg^(-1),respectively.The olsen phosphorus showed strong variation,whereas other soil nutrients displayed only moderate variation.The exponential model was the best-fit model for pH,total nitrogen,olsen phosphorus,available potassium,and slowly released potassium,and the Gaussian model was the best-fit model for organic matter and alkali-hydrolyzable nitrogen.Spatial autocorrelation of soil pH and available potassium was moderate,while that of other soil nutrients was weak,indicating that the spatial variation of nutrients was mainly affected by random factors,such as human activities.The spatial autocorrelation of all nutrients was extremely significant,and the spatial correlation order was as follows:olsen phosphorus>available potassium>pH>slowly released potassium>total nitrogen>organic matter>alkali-hydrolyzable nitrogen.In addition,the spatial autocorrelation of olsen phosphorus was significantly greater than that of other nutrients.In general,nutrient distribution was relatively dispersed,with a gradual upward or downward trend in the north-south direction.The areas with high and low nutrient values also had an obvious north-south distribution.