塔里木沙漠公路防护林区土壤微生物的立地条件效应

通过分析来源于塔克拉玛干沙漠腹地防护林地的土壤样品,揭示了不同立地条件下防护林土壤微生物的差异及对土壤环境因子的响应规律,主要结论如下:(1)不同立地条件下土壤微生物活性差异极显著,呈现沙垄基部>沙垄中部>沙垄顶部>板结平沙地>流沙地的规律,而土壤深度间微生物数量表现为10～20cm>20～35cm>0～10cm,差异不明显。(2)三种微生物对环境因子的响应有所差异,细菌与土壤总孔隙度、含水量有显著正相关关系,与全K含量显著负相关;放线菌与全P、全K和全盐含量明显负相关,与全N正相关;真菌与全K、全盐含量负相关,与有机质含量和孔隙度大小正相关。(3)土壤不同深度范围内土壤因子对微生物活性的影响程度不同,0～10cm土层主要取决于有机质和N素含量;而土壤盐分状况和孔隙结构对10～20cm微生物较为重要;20～35cm土层中微生物需要满足一定养分供应和土壤结构。因此,土壤微生物对不同立地条件下土壤环境条件响应不同,微生物种群数量表现出一定差异,最终可能影响到微生物在土壤养分转化和促进土壤发育中的作用。

Effect of Site Conditions on the Soil Microbe of Tarim Desert Highway Shelter-forest System

By analyzing the soil samples from the hinterland of Taklimakan desert shelter-forest,the patterns of the differences of soil microbes and their responses to soil factors under different site conditions were studied.The main conclusions were below:(1) The differences of soil microbe activities between any two different site conditions were extremely obvious,and the base of longitudinal dune>the middle of dune>the top of dune>harden flat sand> shifting sand,but no significant difference in different depths.(2) there were different responses to soil factors among three types of microbes,and they had marked positive correlations between bacteria quantity and total porosity,soil moisture content,respectively,and then it notably negatively correlated with the content of soil total potassium.As to actinomyces,it had obvious negative correlations with the contents of total phosphorus,total potassium and moisture in soil,and positively correlated with soil total nitrogen content.Fungi quantity was negatively correlated with soil total contents of potassium and salt,positively correlatd with soil organic matter content and porosity.(3) The effects of various soil factors on microbial activity were different in the several successive soil depth ranges,and the activities in the soil depth ranged of 0-10cm depended on the contents of organic matter and nitrogen.But the soil salt condition and porosity structure played a more important role for the microbial activities in the soil depth range of 10-20cm.For the microbe in 20-35cm soil depth,certain nutrient supply and soil structure were necessary.(4) Accordingly,soil microbes from different site situations represented different responses to environmental conditions,so microbial activity was different;ultimately they could affect the function of microbes in the soil nutrient transformation and promoting soil development.