崇明县土壤主要理化指标的空间分布与变异特征

Spatial Distribution and Variability of Main Soil Physical and Chemical Properties in Chongming and Affecting Factors

于上海市崇明县(崇明岛、长兴岛、横沙岛3岛)采集0～20cm表层土壤样品128个,采用经典统计学和地统计学相结合的方法,分析土壤有机质、全氮、有效磷、有效钾含量和土壤电导率、容重、pH值等数据,研究土壤特性的空间分布规律。结果表明:崇明3岛有效磷和电导率的分布具有强变异性,pH值的变异强度最弱,其他土壤特性均具有中等变异强度。土壤容重和pH值具有很强的空间相关性,而土壤有机质、全氮、有效磷和有效钾的空间相关性最弱,其分布受随机因素影响较大。Kriging空间插值分析表明,受农事活动和城镇效应的影响,崇明岛土壤有机质和全氮含量高值区主要集中于人为活动比较密集的地区,土壤容重和pH值分布趋势基本一致,呈现由东西两端向岛中央递减的趋势。崇明岛土壤有机质、全氮、有效磷和有效钾含量两两间呈显著相关关系(α=0.01)。

A total of 128 soil samples were collected from the 0-20 cm topsoils of the three islands of Chongming,Shanghai,using the classical statistics and geostatistics for analysis of soil organic matter,total nitrogen,available phosphorus,available potassium,soil electrical conductivity,soil bulk density and pH,and for further study of spatial variation of the physical and chemical properties.Results show that the spatial variabilities of available potassium and soil electrical conductivity were strong,that of pH was weak,and the others were moderate.Soil bulk density and pH demonstrated a strong spatial correlation while soil organic matter,total nitrogen,available phosphorus and available potassium did not,which shows their distributions are strongly affected by stochastic factors.The Kriging interpolation analysis revealed that the distributions of soil organic matter and total N were affected by farming practices and urbanization with high values found in the areas where human activities were intensive.Soil bulk density and pH were in a similar trend,decreasing gradually from the east and west tips of the island to the center.Soil organic matter,total nitrogen and available potassium in Chongming island were significantly correlated（α=0.01）.