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以两种退耕还林模式的桦木林地、苦竹林地和农耕地(对照)为对象,对各样地土壤微生物优势类群数量的季节性动态变化、垂直分布特征及其与土壤酶活性的相关性进行了研究。结果表明,土壤微生物的优势类群为微球菌属(Micrococcus)、芽孢杆菌属(Bacillus)、链霉菌属(Streptomyces)、游动放线菌属(Actinoplanes)、酵母菌(未定属)、木霉菌属(Trichoderma)这6类。两种退耕还林模式下土壤优势微生物类群数量存在差异,春、夏、秋三季均为苦竹林所占比例最大,冬季为桦木林最大。两种林地和农耕地土壤微生物优势类群数量季节性变化规律为微球菌和酵母菌在夏、冬季较大,春、秋季较少;芽孢杆菌在秋季最大,夏季最小;游动放线菌与木霉菌数量在四季中变化不大;链霉菌是夏季最高,冬季最少。各优势微生物类群数量的垂直分布特征表现为微球菌、游动放线菌、木霉菌随土壤层的加深其数量逐渐降低,芽孢杆菌、链霉菌数量则随土壤层的加深而逐渐增加,酵母菌随土壤层的加深其数量减少,但趋势不明显。两种林地对各优势微生物类群数量的根际效应为:链霉菌和木霉菌的R/S值大于1,酵母菌的R/S值小于1,微球菌和游动放线菌在桦木林的R/S值大于1而在苦竹林小于1。在优势微生物类群和土壤酶之间,微球菌与转化酶,芽孢杆菌与纤维素酶,木霉和游动放线菌与过氧化氢酶,酵母与脲酶呈显著正相关关系。
Based on the two types of birch forest, bitter bamboo forest and farmland (contrast), the seasonal dynamics, vertical distribution and the relationship between soil microbial activity and soil enzyme activity Study. The results showed that the dominant groups of soil microorganisms were Micrococcus, Bacillus, Streptomyces, Actinoplanes, yeast (undetermined), Trichoderma (Trichoderma) these six categories. There were differences in the number of dominant microbial groups in soil between the two models of returning farmland to forestland. The proportion of bitter bamboo forest was the largest in spring, summer and autumn, and the largest in birch forest in winter. The seasonal changes of the number of dominant microbial communities in two kinds of forestland and farmland were Micrococcus and Saccharomyces in summer and winter, less in spring and autumn; Bacillus was the largest in autumn and the lowest in summer; The number of molds did not change much in the four seasons; Streptomyces was the highest in summer and the least in winter. The vertical distribution characteristics of the dominant microbial populations showed that the number of microspacty, actinomycetes and Trichoderma decreased with soil depth, and the number of Bacillus and Streptomyces increased gradually with the deepening of soil layer. With the deepening of the soil layer, its number decreased, but the trend was not obvious. The rhizosphere effects on the dominant microflora in both forestlands were as follows: the R / S value of Streptomyces and Trichoderma was more than 1, the R / S value of yeast was less than 1, and that of Micrococcus and Actinoplast in birch forest R / S value is greater than 1 and less than 1 in bitter bamboo. There was a significant positive correlation between microflora and invertase, Bacillus and cellulase, Trichoderma and actinomycetes, catalase, yeast and urease among dominant microflora and soil enzyme.