基于信息熵的耕地土壤养分与环境影响因子空间相关性研究

目的] 探究耕地土壤养分含量空间格局及与环境因子的空间相关性，为区域耕地土壤施肥管控及农业生态环境保护等相关工作提供理论依据。方法] 以湖北省枣阳市耕地为研究对象，选取土壤有机质、全氮、速效钾、缓效钾和有效磷5种土壤养分指标，并收集整理成土母质、土壤类型、土壤pH值、高程（DEM）、地表起伏度、坡度、植被覆盖度指数（NDVI）、平均气温、平均降水量和土地利用方式10种环境影响因子，利用普通克里金插值和信息熵原理，分析每种土壤养分的空间分布特征以及每种土壤养分空间分异特征与环境因子的相关性。结果] 枣阳市土壤缓效钾空间异质性不明显，全域含量水平较高；其他4种养分均表现出不同程度的空间异质性。信息熵结果表明，5种土壤养分含量空间格局与成土母质、土壤类型和气候因子相关性均较强但相关程度存在差异；地形因子与全氮和有机质含量空间相关性较强，土壤pH值与土壤速效钾、缓效钾和有效磷相关性较强。结论] 枣阳市土壤养分格局受自然因素影响较强，但相关性指数K值都较低，说明受到人为施肥与农作物消耗以及灌溉排水导致的土壤水化学反应及养分流失的影响。

Spatial Correlation Between Soil Nutrients and Environmental Factors in Cultivated Land Based on Information Entropy

Objective] The spatial pattern of soil nutrient content in cultivated land and its spatial correlation with environmental factors were studied, in order to provide a theoretical basis for regional cultivated land soil fertilization control and agricultural ecological environmental protection.Methods] Taking the cultivated land in Zaoyang City of Hubei Province as the research object, five soil nutrient indicators including soil organic matter, total nitrogen, available potassium, slow-acting potassium and available phosphorus were selected, and 10 environmental factors including soil parent materials, soil types, soil pH value, Elevation (DEM), surface undulation, slope, vegetation coverage index (NDVI), average temperature, average precipitation, and land use types were collected to analyze the spatial distribution characteristics of each soil nutrient and the correlations between the spatial differentiation characteristics of each soil nutrients and environmental factors by using ordinary Kriging interpolation and information entropy principle.Results] The spatial heterogeneity of soil slow-acting potassium in Zaoyang City was not obvious, and the content of the whole area was relatively high; the other four nutrients all showed different degrees of spatial heterogeneity. The results of information entropy showed that the spatial patterns of the five soil nutrient contents were strongly correlated with soil-forming parent materials, soil type and climate shadow, but the degree of correlation was different; the topographic factors had a strong spatial correlation with total nitrogen and organic matter contents, and soil pH value. The value had a strong correlation with soil available potassium, slow-acting potassium and available phosphorus.Conclusion] The soil nutrient pattern in Zaoyang City is strongly affected by natural factors, but the correlation index K value is low, indicating that it is affected by the chemical reaction of soil water and nutrient loss caused by man-made fertilization, crop consumption and irrigation and drainage in the later period.