青海湖湖东沙地固沙植物的土壤改良作用

Soil Amelioration Benefit of Sand-binding Vegetation in East-shore Sandy Land of Qinghai Lake

为探究高寒沙地固沙植物的土壤改良作用及其与植物种差异和地形部位差异的关系,以青海湖克土沙地9年林龄的沙棘、乌柳、樟子松、小叶杨和沙蒿5种固沙植物群落为研究对象,开展各群落不同深度土层的土壤粒度、水分和养分性质检测。研究表明,固沙植物主要能减少土壤颗粒组分中的中砂、粗砂比例,增加表层土壤容重和有机质含量,同时提高中层和深层土壤的含水量和表层土壤的碱解氮、速效钾含量。在沙丘部位差异上,丘间地的土壤含水量和养分含量显著高于迎风坡和丘顶,尤以樟子松和小叶杨沙丘突出。综合对比近6年,沙棘、乌柳和沙蒿的土壤改良速度较快,保水保肥能力突出。樟子松和小叶杨沙丘除表层土壤外,中层和深层土壤的改良作用较为缓慢与微弱。

Research on artificial forests soil properties in alpine sandy land is mainly designed for observing soil amelioration function and exploring its species and slope position difference. Five sand-binding vegetation communities(Hippophae rhamnoides, Salix cheilophila, Pinus sylvestris, Populus simonii and Artemisia desertorum) with ages of 9 years in Ketu Sandy Land were selected and analyzed by soil grain size, water content, nutrients and other physical and chemical properties in different soil depth layers. The primary soil improvements for all the re-vegetated sand dune communities were reflected from a decrease in middle and coarse sand particle percentages, increases of soil density and soil organic matter contents in upper soil layer, water content in middle and deep soil layer, and significant increases of available nitrogen and potassium accumulation in upper soil depths. The soil water and nutrient contents in inter-dune part is obviously higher than those in windward and top parts of sand dune, especially for the P. sylvestris and P. simonii dunes. In conclusion, all vegetation species showed positive soil amelioration benefits after 6 years. The H. rhamnoides, S. cheilophila and A. desertorum communities featured better and quicker soil amelioration effects than P. sylvestris and P. simonii communities, as the latter communities were heavily disturbed by wind-sand hazard, and their middle and deep layers of soil showed a weak and slow-procession effect of soil improvement, comparatively.