西双版纳热带雨林和橡胶林土壤斥水性比较

Comparison of water repellency in the tropical rainforest and rubber plantation in Xishuangbanna,SW China

利用2008年8月至2009年7月采集于西双版纳热带雨林和人工橡胶林2种代表群落中82个土样,通过测定其潜在和实际斥水性,比较了2种林型土壤斥水性在不同温度和季节间的变化,并探讨了土壤斥水性与环境因子间的关系.结果表明:①2种林型下土壤大部分表现出较弱的斥水性,且橡胶林下土壤实际斥水性明显高于热带雨林,而土壤潜在斥水性则橡胶林显著低于热带雨林;②温度可以明显降低土壤斥水性强度,但两种林型间温度对土壤斥水性的影响无明显差别;③在干季,热带雨林和橡胶林下土壤斥水性无差异,在雨季则橡胶林显著高于热带雨林.相关性分析表明:土壤斥水性与土壤有机质含量无明显相关性(R2=0.33),而与土壤含水量呈显著正相关(R2=0.64);土壤质地对土壤实际斥水性有显著影响.研究表明土壤含水量和土壤质地是影响西双版纳地区土壤斥水性的主要因素,因此在恢复地表植被存在困难的前提下,解决西双版纳地区水土流失问题的关键是如何控制土壤含水量以及改善土壤质地条件.

Eighty-two soil samples were collected during August 2008 and April 2009 for water repellency analysis from tropical rainforest and rubber plantation in Xishuangbanna,Southwest China.The influence of vegetation,temperature and season on soil repellency and the relationship between repellency and environment factors were studied in this paper.The results show that most of the soil in two types of vegetation show very weak repellency and the actual repellency in rubber plantation is higher than that in the rainforest.In contrast,the potential repellency is lower in rubber plantation.The effect of temperature change on the two kinds of forest was equivalent.And the repellency will change easily under the lower temperature.In dry season,no significant differences were observed about the repellency of the two type's forest.While in rainy season,the repellency of rubber plantation soil was significantly higher than that of the rubber plantation soil.Water repellency was positively correlated with the soil water content(R2 = 0.33) but not with soil organic matter content(R2 = 0.64) .And the soil texture had a great effect on the water repellency.So it concluded that the key factors which determined the soil water repellency in Xishuangbanna were soil water content and soil texture.And vegetation change was the main factor which lead to large scale water lost and soil erosion.So in order to solve this problem we should try our best to do by controlling the soil water content and ameliorating the soil texture.