基于地理探测器的宝鸡市农田土壤养分影响因子分析

Influencing Factors of Soil nutrients in Farmland of Baoji Based on Geographical Detector

为分析陕西省宝鸡市农田土壤养分空间变异情况及其影响因素,选取土地利用类型、成土母质、土壤类型、高程、坡度、坡向、年均降水量、年均气温8种影响因子,借助地理探测器分析各因子对土壤有机质(SOM)、有效磷(AP)、速效钾(AK)、全氮(TN)养分空间变异的影响。结果表明:造成SOM空间变异主要三因子分别为土地利用方式、土壤类型、年均气温;AP与AK的主要影响因子为成土母质、高程、土地利用方式;对TN解释力较大的三因子为土地利用方式、土壤类型、成土母质。即各因子对土壤养分空间变异原因的解释力存在一定的差异,气温变化对TN和SOM影响较大,高程是对4种土壤养分解释力较强的地形因子。交互探测器探测结果表明:两因子间的交互作用对养分的解释力均强于单因子,地形因子与其他因子交互之后解释力显著增强。影响因子与养分之间主要作用方式为双协同作用和非线性协同作用。随着高程的变化,4种养分含量呈现不同的变化趋势。此外,通过与Pearson相关系数法分析结果进行对比,发现地理探测器可以得到与之一致的因子重要性排序,适用于该区域土壤养分的研究。

Soil nutrients are essential indicators for land quality assessment and fertility monitoring.To investigate spatial variation andits influence factors in Baoji,eight types of impact factors including land use type,soil parent material,soil type,elevation,slope,aspect,annual average precipitation and annual average temperature were selected and importedinto Geographical Detector.The spatial variabilities of four soil nutrients(soil organic matter,SOM;available phosphorus,AP;available potassium,AK;total nitrogen,TN)were analyzed.The results showed that the spatial variability of SOM was mainly affected by land use type,soil type and annual mean temperature.The main influencing factors of AP and AK were soil parent material,elevation and land use type and those of TN were land use type,soil type,and soil parent material.The annual mean temperature had significant impacts on TN and SOM.The elevation was a topographic factor with strong explanatory power.The explanatory power for soil nutrients by the interaction between the two factors was stronger than that by the single factor,and that by the interpretation between the topographic factor and other factors was significantly enhanced.The interpretation between impact factor and soil nutrients showedthe primary dual synergy and nonlinear synergy modes.The four nutrients showed different trends with the change of elevation.Besides,the Geographical Detector obtained the same resultof the significance order of soil nutrients as the Pearson correlation coefficient and was more suitable for the study of soil nutrients.In the future production activities,the fertilization strategy should be adjusted in combination with different soil nutrient conditions,and soil testing and formula fertilization should be carried out scientifically and rationally to achieve sustainable use of soil resources.