江淮丘陵地区土壤养分空间变异特征--以安徽省定远县为例

Spatial Variability Characteristics of Soil Nutrients in Jianghuai Hilly Region——A Case Study of Dingyuan County, Anhui Province

以安徽省江淮丘陵地区的定远县为例,利用测土配方施肥获取的1 401个农田表层样点数据,运用地统计学方法和GIS技术研究了土壤有机质（SOM）、全氮（TN）、速效磷（AP）和速效钾（AK）含量的空间变异特征及其影响因素。结果表明,定远县SOM含量为17.74 g/kg,TN含量为1.04 g/kg,AP含量为13.45 mg/kg,AK含量为115.00 mg/kg,属中等水平。变异系数介于28.85%~73.38%,属中等变异强度。地统计分析表明,定远县土壤养分的变异函数符合指数模型,具有中等强度的空间自相关性,SOM和TN的空间自相关性稍强。土壤养分在空间上呈块状分布,SOM、TN和AK的空间分布总体上东南高、西北低;AP总体上西高东低。土壤养分空间变异主要受地形和土壤类型影响。

In this research, Dingyuan County was chosen as a case in the Jianghuai hilly region. A total of 1 401 soil samples were obtained from soil testing and formulated fertilization of Dingyuan County. Spatial variability of organic matter （SOM）, total nitrogen （TN）, available phosphorus （AP）, and available potassium （AK） in the surface layer of soils in this region were analyzed using the Geostatistics and GIS method. The factors influencing the spatial variability of soil nutrients were also investigated by means of correlation analysis and variance of analysis. The results showed that the average contents of SOM, TN, AP and AK were 17.74 g/kg, 1.04 g/kg, 3.45 mg/kg and 115.00 mg/kg, respectively. The coefficients of variation for these soil nutrients ranged from 28.85% to 73.38%, belonging to a moderate level of variation. Geostatistical analysis suggested that semivariance functions of soil nutrients were fitted by exponential model. There was a moderate spatial autocorrelation among these soil nutrients. Spatial autocorrelation of SOM and TN was slightly stronger than that of AP and AK. Soil nutrients were distributed spatially in patches. The contents of SOM, TN and AK decreased along the direction from southeast to northwest in spatial distribution. AP content decreased from west to east of Dingyuan County. Topography and soil types were main factors influencing the spatial variability of soil nutrients in Dingyuan County.