淮北平原农田土壤养分空间变异特征--以安徽省蒙城县为例

Spatial Variability Characteristics of Soil Nutrient in North Plain of Anhui Province-A Case Study of Mengcheng County, Anhui Province

以安徽省淮北平原的蒙城县为例,利用测土配方施肥获取796个农田表层样点数据(0~20 cm),运用地统计学方法研究了土壤有机质(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,蒙城县SOM含量为17.14±2.70 g kg^(-1),TN含量为0.85±0.14 g kg^(-1),AP含量为16.63±9.66 mg kg^(-1),AK含量为129.63±35.24 mg kg^(-1),属中等水平。变异系数介于15.75%~58.09%,属中等变异强度。地统计分析表明,蒙城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,AP和AK的空间自相关性稍弱。土壤养分在空间上呈块状分布,SOM、TN和AK的空间分布总体上北高南低、在东南—西北方向上变异较强,在西南—东北方向上变异较弱。AP含量总体上由北到南,先降低再升高。

In this research, Mengcheng County was chosen as a case in the North Plain of Anhui Province. A total of796 topsoil samples（0 ～ 20 cm） were collected from soil testing and formulated fertilization of Mengcheng County.Spatial variability of soil organic matter（SOM）, total nitrogen（TN）, available phosphorus（AP）, and available potassium（AK） in the surface layer were analyzed using the Geostatistics method and its influencing factors by variance of analysis. Descriptive statistics showed that the SOM and TN contents, respectively, varied in 17.14 ± 2.70 g kg^（-1）and0.85 ± 0.14 g kg^（-1）; AP and AK contents, respectively, varied in 16.63 ± 9.66 mg kg^（-1）and 129.63 ± 35.24 mg kg^（-1）.The coefficients of variation ranged from 15.75% to 58.09%, belonging to a moderate level of variation. Geostatistical analysis suggested that semivariance models of soil nutrients were fitted by exponential model. There were moderate spatial autocorrelation of soil nutrients. Spatial correlation of SOM and TN were slightly stronger than AP and AK.Spatially, soil nutrients were distributed in a patch. SOM, TN, and AK decreased from north to south in spatial distribution. The variations of SOM, TN, and AK were severe in the direction of southeast to northwest and were weak in the direction of southwest to northeast. AP content decreased firstly, and then increased from north to south of Mengcheng County.