湟水流域土壤有机质和速效磷空间布局分析

为分析青海省湟水流域土壤有机质(soil organic matter, SOM)和速效磷(available phosphorus, AP)含量空间分布特征及其影响因子，运用地统计学方法分析其空间分布特征，选取高程、坡向、坡度、土壤类型、土壤pH、归一化植被指数(normalized difference vegetation index, NDVI)、气温、降水量和土地利用方式共9种影响因子，借助地理探测器研究各因子对SOM和AP的影响。研究表明SOM平均值为28.26 g/kg，AP平均值为54.30 mg/kg；SOM和AP的变异系数为39.54%和58.47%，属于中等变异程度。空间插值结果显示SOM含量在空间上呈现西北高，东南低的趋势，SOM由北向南逐渐降低；AP含量呈现中部高于两端的趋势。因子探测及Pearson相关性分析结果表明：造成SOM空间变异的三大因子顺序为：高程>气温>土壤类型；对AP含量解释程度顺序是：土壤pH>高程>土壤类型。SOM含量与高程和土壤pH两种因子呈现正相关关系，AP则相反，呈现负相关，SOM和AP空间分布都与高程有关；气温均对两种土壤养分有影响；高程因子是决定湟水流域SOM含量的主导因子，而影响AP空间分布的主导因子是土壤pH。影响因子相互作用时，呈现双线性增强或者双因子增强。两因子交互作用对SOM和AP解释力均高于单因子，说明导致SOM和AP空间分布差异的因子具有复杂性。研究得到湟水流域空间尺度上SOM和AP含量分布，并结合湟水流域9种影响因子对其含量进行分析，为湟水流域的数字农业管理和精准施肥以及耕地土壤改良和质量的提升提供了有利基础。

Analysis on the Spatial Distribution of Soil Organic Matter and Available Phosphorus in Huangshui River Basin

In order to analyze the spatial distribution characteristics and influencing factors of soil organic matter (SOM) and available phosphorus (AP) in Huangshui River Basin of Qinghai Province, the geostatistics method was used to analyze the spatial distribution characteristics. Nine influencing factors, including elevation, aspect, slope, soil type, soil pH, normalized difference vegetation index (NDVI), temperature, precipitation and land use type. The effects of each factor on SOM and AP were studied by geographical detector. The results show that the average content of SOM is 28.26 g/kg, and the mean value of AP is 54.30 mg/kg. The coefficients of variation of SOM and AP are 39.54% and 58.47%, which belong to medium variation. The spatial interpolation results show that the SOM content is high in the northwest and low in the southeast, and the SOM gradually decreases from north to south. The content of AP in the middle is higher than that in both ends. The results of factor detection and Pearson correlation analysis show that the order of the three factors causing SOM spatial variation is elevation > temperature > soil type; the order of AP content interpretation is: soil pH > elevation > soil type. SOM is positively correlate with elevation and soil pH, while AP is negatively correlate with elevation. Temperature has an impact on the two soil nutrients; elevation factor is the dominant factor determining SOM content in Huangshui River Basin, and soil pH is the dominant factor affecting AP spatial distribution. The interaction of the influencing factors shows bilinear enhancement or double factor enhancement. The explanatory power of the two-factor interaction on SOM and AP is higher than that of the single factor, indicating that the factors that lead to the spatial distribution differences of SOM and AP are complex. The SOM and AP content distributions at the spatial scale of Huangshui River Basin are obtain and combine with nine influencing factors in Huangshui Basin to analyze their content, which provides a favorable basis for digital agricultural management and precision fertilization in Huangshui River Basin as well as arable soil improvement and quality improvement.