柯柯牙城郊防护林主要造林类型土壤改良效应研究∗

摘要

城郊防护林作为城市的生态基础设施为城市及其居民持续获得自然生态服务提供保障。本文对新疆南部典型绿洲城市——阿克苏市郊柯柯牙人工防护林工程的土壤修复与改良效应进行定量研究，以该地区4种不同造林类型（红枣林、香梨林、苹果林和杨树林）土壤为研究对象，实测观察其土壤理化性质及其垂直分布变化，对比分析4种林型下土壤不同因子的差异及各因子间的相关性，揭示了人工防护林建设对裸露沙地土壤的综合改良效应。结果表明：（1）人工造林使原沙地土壤物理结构得以改善、土壤水分大幅提升、pH值和可溶性盐含量有效降低、土壤有机质和养分含量显著提高；（2）红枣林地土壤物理改良效果最为明显，对于可溶性盐而言，杨树林地土壤含盐量最低，经济（果园）林地呈现中层土壤(10∼30 cm)高于表层和底层土壤的规律，体现了人工漫灌的“压盐”作用；（3）各林型对土壤化学因子改良效果存在差异，土壤各因子之间存在着较为显著的相关性；改良后的土壤质量优劣程度排序为：苹果林地>红枣林地>香梨林地>杨树林地。%Peri-urban shelterbelt as an ecological infrastructure of the city that supplies safeguard for urban and its residents to obtain sustainable services provided by natural ecosystem. In this paper, we did quantitative analysis of the effects of Kokyar artificial afforestation project in peri-urban area of Aksu, a typical oases city in Sothern Xinjiang - on soil remediation and improvement. Soil samples of four main forest types (Apple, Jujube, Pear, Poplar forest) were selected as the research object, based on observation of the physical and chemical properties of the soil and its vertical distribution change, we made comparative study on the differences of soil physicochemical factors and their relationship under different forest types, in order to assess the improvement effect of shelterbelt forest construction on bare sandy soil. The results showed that: (1) Artificial afforestation pro ject had a significant effect on improvement of physical structure of sandy soil by raising its soil moisture, reducing pH and soluble salt content and increasing soil organic matter and nutrient content; (2) The soil improvement effect of Jujube orchard forest was obvious. For soluble salt, lowest soil salinity were observed in Poplar forest stand while soil salinity of middle soil layer (10-30cm) within economic orchard forest was higher than the soil salinity top and bottom soil layers. It reflected that the“press salts”role of artificial irrigation;(3) Various forest types had different improvement effects on soil physical chemical properties. There was significant correlation between each soil factors. Soil quality after improvement was listed as: Apple >Jujube>Pear>Poplar Forest.