塔里木沙漠公路防护林土壤微生物的生态分布特征

对不同立地类型、不同造林年限、不同树种、不同季节的防护林土壤微生物数量及区系组成进行研究 ,结果表明 :咸水灌溉条件下塔里木沙漠公路防护林和人工绿地建成后 ,风蚀作用减弱 ,流动沙丘逐渐固定 ,土壤结构和养分状况得到改善 ,微生物活性大幅度提高 ;在土壤微生物区系组成中 ,细菌占绝对优势 ,放线菌次之 ,真菌最少 ;表层微生物数量远多于下层土壤 ;林地外围距林缘近的土壤微生物活性较强 ,3m以外微生物数量已接近流沙微生物量 ;3类土壤微生物分布具不同的季节性规律 ,且不同立地类型土壤微生物分布差异明显 ;随造林年限的增加 ,防护林的改土作用更加显著。

Study on Ecological Distribution of Soil Microorganisms in Taklimakan Desert Highway Shelter-forest

This paper studied the quantities and fauna component of soil microorganism in shelter forest under different conditions of site, shelter forest with different ages, shelter forest in different seasons, and shelter forest composed by different kinds of plants. The results indicated that with Taklimakan desert highway shelter forest and artificial greenbelt set up under condition of irrigating by saline water, wind erosion decreases, and shifting sand was fixed, so soil structure and nutrient status was improved, and the quantities of soil microorganisms increased sharply. Among soil microorganisms,bacteria were predominant,actinomyces the next and fungi the least. There were more microorganisms in the upper soil than ones in down soil. Outside shelter forest, soil microorganisms near shelter forest have higher activity, and the quantity of soil microorganisms over 3 m from shelter forest were almost equal to ones of shifting sand.The quantities of soil microorganisms vary with seasons, and there are distinct difference among quantities of soil microorganisms of forests under different condition of site.The quantities of microorganisms and soil nutrient increase greatly with time elapse, and the change will be much more obvious.