不同密度麻疯树林地对土壤微生物的影响

为了科学评价不同密度麻疯树林地的土壤肥力变化，通过对土壤微生物的研究，结合水肥调控技术等措施，来改善不同密度麻疯树林生态系统的生态环境，维持其林地生产力水平，为科学营造和管理麻疯树林提供基础数据和理论依据，使之加快麻疯树的规模化发展，对云南省双柏县3种不同密度麻疯树林地的土壤微生物数量和类群进行对比研究，并对麻疯树林地微生物进行聚类分析及多样性指数分析。结果表明：3种林地土壤微生物的数量有明显差异，样地2最多，样地1和样地3相差不大；不同土层的微生物数量变化也有所不同，0~15 cm之间土壤细菌、真菌数量逐渐上升，11~15 cm处达到峰值；随着土壤深度的增加，细菌、真菌数量又呈现下降趋势；样地2物种多样性指数也显著高于其他2种林地，这可能是由于适度的密度有利于土壤微生物的生长。因此，在种植麻疯树时，适宜密度为2 m×3 m。

The Effect of Jatropha curcas L. Forests with Different densities on the Soil Microorganism

In order to scientifically evaluate the soil fertility changes in the different densities of Jatropha curcas L. forest, the author did the soil microorganism research, with combination of water and fertilizer control technology measures, to improve the different densities of Jatropha curcas L. forest ecosystem environment, maintain its productivity level, to provide the basic data and the theoretical basis for scientific construction and management of Jatropha curcas L. forest, to accelerate its＇ development. By comparing the soil microbial quantity and taxa to the three different densities of Jatropha curcas L. forests in Shuangbai, Yunnan Province. In addition, the author did the cluster analysis, and diversity index analysis to the Jatropha curcas L. forest of microorganisms. The results indicated that the three woodland of soil microorganism variance were remarkable, sample 2 was most, sample 1 and sample 3 had no differences. The vertical distribution showed that the microorganism quantity had difference, 0-15 cm soil bacteria, fungi number rose gradually, 11-15 cm peak; with the increase of soil depth, the number of fungi, bacteria showed a downward trend. Sample 2 species diversity index was also significantly higher than the other two kinds of forest lands, this might be due to moderate density was beneficial to the growth of the soil microorganism. Therefore, in the cultivation of Jatropha curcas L., the most suitable density of 2 m×3 m.