黄河三角洲土壤盐分空间变异性与合理采样数研究

以黄河三角洲地区一块约520hm^2的田块为研究区，采用经典统计学和地统计学方法进行不同层次土壤盐分（0～20cm，20～60cm，60～100cm，100～140cm）的空间变异及其合理采样数量研究。结果表明：研究区土壤盐分普遍较高且表聚作用明显；各层土壤盐分均属于中等变异强度;受结构性因素和随机性因素的共同作用，各土层盐分均具有中等的空间相关性。对Kriging插值结果分析表明，土壤盐分的空间分布受微地形和气候条件的影响较大．且研究区各土层盐分分布存在着空间上的相似性。应用Cochran公式和分层采样方法对合理采样数量进行了分析，发现采用分层采样方法可以有效降低采样数量，且采用最适分配法可以获得最为理想的采样数量，该方法较比重分配法采样数降低幅度最大达35％左右。该研究为黄河三角洲地区盐渍土地的科学管理、改良以及利用提供一定的理论依据和技术参考。

Study on Spatial Variability and Appropriate Sampling Quantity of Soil Salinity in Yellow River Delta

Spatial variability and appropriate sampling quantity of soil salinity for various depth layers(0~20 cm,20~60 cm,60~100 cm,and 100~140 cm) was measured and analyzed by using statistics and geo-statistics,which was performed in an approximately 520 hectare field in the Yellow River Delta.The results indicated that soil salinity for all depth layers were generally high and salt accumulation at the surface soil layer was significant;Soil salinity for all depth layers exhibited moderate spatial variation and moderate spatial autocorrelation resulting from compound impact of structural and stochastic factors.The spatial distribution maps of soil salinity interpolated by Kriging interpolation showed apparently that the spatial distribution of soil salinity was mostly controlled by micro-topography and climatic conditions,and there existed spatial correlativity between soil salinity distribution maps of different depth layers.Analysis on the appropriate sampling quantity,which was determined by using Cochran and distributed sampling methods respectively,showed that distributed sampling methods could reduce the appropriate sampling quantity effectively,the appropriate sampling quantity for rational distributed sapling was the most reasonable and practical,and rational distributed sampling could furthest reduce some 35% of the appropriate sampling quantity compared with weighing distributed sampling.The research results can serve as a theoretical and technical basis for the scientific management,amelioration,and utilization of saline soils in the Yellow River Delta.