苏北泥质海岸盐碱地杨树纯林土壤的改良效应

为了深入探讨林分对土壤的改良作用,在苏北泥质海岸的大丰林场选择不同林龄(6a、7a、16a、19a)的杨树纯林,16a水杉纯林及滩涂芦苇地作为对照,测定其标准样地的土壤密度、有机质质量分数、全N及全P质量分数、pH值等土壤理化性质,将不同树龄(杨树)之间,不同树种(杨树与水杉)之间,林地和滩涂芦苇地之间的土壤理化性质做对比分析。结果表明:1)杨树林对土壤具有明显的改良作用,可以减少土壤密度,增加有机质、全N、全P质量分数,降低pH值。2)杨树林改良土壤的作用与林龄、根系分布密切相关。林龄越大,改良土壤的作用能强;土层由上至下,根系分布逐层减少,改良土壤的作用也逐层削弱。

Study on soil improvement effect of the Populus tomentos pure forest of saline land on the muddy sea-coast in northern Jiangsu Province

In order to understand the ability of forest land to improve soil properties, at the Dafeng forest farm of the muddy sea-coast in northern Jiangsu Province, pure forest of Populus tomentos at the different ages （6a,7a,16a,19a） , and 16-year-old pure forest of Metasequoia glyptostroboides were selected for the study and the beach land of Phragmites communis was selected as control group, the physical and chemical properties of of soil were studied, such as bulk density, organic matter content, total nitrogen content, total phosphorus content and pH value of soil. The effect of the different age in the same species, the different species in the same age, the forest land, the beach land of Phragmites communis on the physical and chemical properties of soil was discussed. The paper gives out some research results as follows. 1 ） the Populus tomentos pure forest has a good ability to improve soil properties, such as reducing bulk density and pH value, increasing the content of organic matter, total nitrogen and total phosphorus. 2） The ability of soil improvement is closely related to forest age and root distribution. The higher forest age is, the stronger the ability of soil improvement is. With the increased soil depth, root number decreased gradually, which leads to the reduction of ability of improving soil properties layer by layer.