基于地统计学烟区土壤养分及pH值空间异质性分析——以重庆市酉阳县岩溶区为例

调查了解土壤养分及 pH 值空间异质性特征是制定烟区土壤养分管理与施肥决策的前提。本研究基于经典统计学和地统计学方法,分析了酉阳烟区土壤表层 pH 值及土壤养分要素的空间异质性特征。结果表明：酉阳烟区土壤有机质含量丰富,有效磷较缺乏；土壤养分指标的变异系数在13.11%-71.46%之间,有效磷的变异系数最大,而有机质、全氮、碱解氮在土壤中比较稳定；土壤有机质和全氮、全磷、碱解氮和有效磷呈极显著的正相关,pH 值和有效磷和速效钾呈极显著的负相关；有机质、全氮、全磷及速效钾的变异函数曲线理论模型符合指数模型,而 pH 值和碱解氮则与球状模型拟合较好；全氮、碱解氮、全磷及有效磷表现出中等空间相关性,而有机质、全钾及速效钾的空间相关性表现较弱；分维数大小表现为：全钾的分维数最大,pH 值、速效钾、有机质其次,全氮、碱解氮最少；土壤养分及 pH 值空间分布在东西和南北方向具有显著性差异,且在东西方向上的变异要高于南北方向。酉阳烟区土壤养分空间相关性不强,说明地形、施肥及耕作等随机性因素能够显著影响烟区土壤养分空间异质性。

Spatial heterogeneity of soil nutrients and pH in tobacco area based on geostatistics: A case study in a karst area of Youyang county, Chongqing

Evaluation of spatial heterogeneity of soil nutrients and pH forms a basis for management of soil nutrients and fertilization in tobacco-growingareas. In this paper, the spatial heterogeneity of soil nutrients and pH in the tobacco-growing area of Youyang county was evaluated using classical statistics and geostatistics. The results indicated rich organic matter and poor availability of phosphorus in the study area; the variation coefficients for eight soil nutrient indicators ranged from 13.11% to 71.46%. The variable coefficient of available phosphorus was the largest among the indicators, while organic matter, total nitrogen and available nitrogen were stable. A significant positive correlation between organic matter and total nitrogen, total phosphorus, available nitrogen and available phosphorus was noticed, while a clear negative correlation between pH and both available phosphorus and potassium was identified. The semivariograms for soil organic matter, total nitrogen, total phosphorus and available potassium were all well fitted using the exponential curve model, while the correlation between pH and available nitrogen fitted well using the spherical model; total nitrogen, total phosphorus, available nitrogen and potassium had moderate spatial correlation, and other soil nutrient indicators showed weak spatial correlation. The spatial distribution of soil nutrients and pH in the east-west direction and the north-south direction area is significantly different, and the variation of spatial distribution in the east-west direction was larger than in the north-south direction. The spatial correlation of soil nutrients in tobacco-growing area of Youyang county is not significant, therefore, it can be concluded that the spatial heterogeneity of soil nutrients is mainly affected by the topography, fertilization, tillage and other potential factors.