河水漫溢对塔里木河下游土壤及植被的影响

Effect of river-flooding on soil physical-chemical properties and vegetation

通过比较和分析塔里木河下游在输水过程中形成的漫溢干扰对土壤理化性质和天然植被的影响和分析漫溢作用下土壤理化性质的变化特点,对河水漫溢干扰对下游天然植被恢复的作用进行了探讨,为塔里木河下游的生态恢复工程提供理论依据。从漫溢区与非漫溢区土壤理化性质的对比结果看:(1)同一观测断面内漫溢区的粘粒含量大于非漫溢区,多次漫溢区粘粒含量大于漫溢次数少的区域,随着漫溢次数的增加,土壤中细沙和极细沙含量显著下降,中粉沙和粗粉砂含量增加,这主要是地表过水对土壤中的颗粒进行冲刷和沉积造成的结果。(2)漫溢增加了土壤的含水量和容重,对土壤有紧实作用。(3)漫溢后土壤的养分的淋洗与沉降作用明显,表明漫溢作用影响了土壤养分在表层的分布。这些土壤理化性质的变化从一定程度上解释了为何漫溢后地表植被的长势和种类有了明显的变化。

In order to examine and analyze the influence of the river flooding disturbance on soil physical-chemical properties and vegetation,the comparative study on soil physical and chemical properties were carried out.The research purpose is try to provid ecological restoration proof for the lower reaches of Tarim River.Species richness,cover degree and soil bulk density,mechanical composition,nutrient,salt,which were investigated and analyzed on typical transects in flooded sites and non-flooded sites in the lower reaches of Tarim River.The influence of the river-flooding on the vegetation restoration was discussed though the changes of soil physic-chemical properties and vegetation fore-and-aft river-flooding.The results show as follows：（1）The contents of clay grain in river-flooding area is higher than non-flooding area,the contents of clay grain in less-flooding area is lower than in several times of river-flooding area in the same observed sites.With the times of flooding increasing,the contents of medium,fine and very fine sands decreased significantly,but the contents of medium and coarse silts increased,these phenomena may be aroused by water washing out and the deposits of soil sediment.（2） Soil moisture contents and bulk density are increasing with the river-flooding,so the river-flooding made the soil compaction.（3）The process of eluviation and sedimentation on soil nutrient are evident,which aroused the distribution of soil nutrient changed in the surface of soil-layer after flooding.From these changes of soil physical-chemical properties,it can be explain the obvious changes of vegetation coverage and species diversity in the river-flooding area.