测定了连云港沙质海岸刺槐纯林、杨树纯林、刺槐×杨树混交林、美国白蜡×桑混交林、苦楝×桑混交林5种模式防护林林地土壤理化性质,以附近来造林的草地为对照,分析了各林地的土壤理化性质,对5种模式防护林地的土壤理化特性进行聚类分类.结果表明:防护林能减少土壤密度,增大孔隙,改善土壤颗粒组成,增加土壤有机质和速效养分,降低pH值;不同林龄和树种改土能力不同；表层(0＜d≤10 cm)土壤有机质与速效N、速效P、速效K、pH值之间呈显著相关性;表层(0＜d≤10 cm )土壤密度与总孔隙度、非毛管孔隙度之间也呈显著相关性;5种防护林地经聚类后,分为4类,其改土能力大小依次为刺槐纯林＞刺槐×杨树混交林＞杨树纯林＞新造林和对照地.%An experiment was conducted to determine physical and chemical properties of the soils in five types of shelter forests (Robinia pseudoacacia pure forest, Populus spp. Pure forest, Robinia pseudoacacia-Populus spp. Mixed forest, Fraxinus Americana-Morus alba mixed forest, Melia azedarach-Morus alba mixed forest) in Lianyungang coastal sandy land using a neighboring grassland as the check plot. A cluster analysis was made on the soil physical and chemical properties of the five types of shelter forests. Results showed that the shelter forests could decrease soil bulk density and pH value, increase porosity, soil organic matter and available nutrients, and improve soil texture. Different types of forests or forests of different ages exhibited various soil improvement capabilities. Organic matter content in 0-10 cm soil layer was significantly correlated with available N, P, and K contents and pH value. Significant correlations were also observed between soil bulk density and porosity, non-capillary porosity in 0-10 cm soil layer. The shelter forests in Lianyungang coastal sandy land could be classified into four types through cluster analysis. The soil improvement capacity of R. Pseudoacacia pure forest was best, followed by R. Pseudoacacia-Populus spp. Mixed forest, Populus spp. Pure forest, newly afforested area and the check plot.
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