不同退耕还林模式下土壤微生物区系分析

以四川省洪雅县两种主要退耕还林模式的桦木(Betulaluminifera)、苦竹(Pleioblastusamarus)林地为对象,并以农耕地为对照,研究了土壤微生物数量的季节动态变化及这两种林木的根际效应,分析和探讨了这两种模式对土壤微生物数量及其活性的影响。结果表明:(1)土壤微生物数量在不同季节表现出一定的变化规律。两种林地中,微生物数量从春季到秋季一直增加,秋季达最大,冬季最小;在农耕地中,从春季到冬季一直增加,在冬季最大。(2)三大类土壤微生物区系中,细菌数量占绝对优势,放线菌数量次之,真菌数量最少;农耕地全年的微生物总数(干重条件下)最多,苦竹林地次之,桦木林地最少。(3)不同的季节,桦木和苦竹的根际效应各不相同,各季节微生物的R/S值都在1~2,全年的微生物R/S值分别为1.37,1.24。(4)从微生物学总体上评价两种退耕还林模式的生态效益,则苦竹林模式优于桦木林模式。

Analysis on Communities of Soil Microbes Under Different Models of Forest Rehabilitation

Seasonal variation of soil microbial amounts and rhizospheric effect of two forest trees were studied systematically on Betula luminifera and Pleioblastus amarus under two main models of forest rehabilitation, and the cropland was regarded as contrast in Hongya county , Sichuan province. And effect of two models of forest rehabilitation on soil microbial amounts and activities was analyzed and discussed. The main results of study showed that soil microbial amounts were changed regularly in different seasons. Microbial amounts were increased from spring to autumn, and were the most in autumn, and were the least in winter in B.luminifera and P.amarus. But microbial amounts of cropland were increased from spring to winter, and were the most in winter. Bacteria amounts were predominant, actinomyces amounts were the next, and fungi amounts were the least among composition of communities of soil microbes. The sequence of total amounts of soil microbes from high to low was cropland>P.amarus forest>B.luminifera forest in a year. Rhizospheric effect of two forest trees under two models of forest rehabilitation was different during different seasons. And the R/S values of microbes were from 1 to 2 during different seasons, and the R/S values were respective 1.37 and 1.24 in in a year. So the ecological benefit of model of P.amarus was better than B.luminifera by evaluation of total soil microbes.