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机构地区:[1]北京林业大学林业资源学院 [2]北京市共青林场
出 处:《北京林业大学学报》1991年第2期31-36,共6页Journal of Beijing Forestry University
基 金:林业部"七五"攻关项目
摘 要:本文分析了北京市郊区小美旱、刺槐纯林及其混交林内土壤细菌总数及主要细菌生理群的数量,其数量范围为1.39×102个/g土~38.00×106个/g土。并分析了细菌数量、土壤因子和林分生长三者的关系。还测定丁3种林分各土层的固氮酶活性为1.22~1.63,4.05~4.14,3.96~5.06kgN2/ha·a。自生固氮菌的固氮酶活性范围为2.21~139.25n molC2H4/mg·蛋白质·h。The bacteria, their numbers and their three main physiological groups, have been analysed from nine soil horizons under Populus popularis, Robinia pseudoacacia and their mixed stands. The type of vegetation significantly affected the bacterial numbers present in the soil. In three of the plantations they were greatest under the mixed stand, and least under the Robinia stand. Cellulose decomposing bacteria were greatest in horizon A under the Populus Stand. Even within one vegetation type, large differences in bacterial numbers occurred between soil horizons. The variations in bacterial counts also correlated with some soil factors, such as the percentage of total nitrogen and organic matter, temperature and C/N ratio of organic matter.The nitregen fixing capacity of three soil profiles analysed by means of acetylene reduction methods with gas chromatography were 1.22~1.63, 4.05~4.14, 3.96~5.06kgN_2/ha·a,. Different kinds of N_2 fixation bacteria were isolated in the soil under three plantations with nitrogen fixing capacity of 2.21~139.25 n mol C_2H_4/mg protein·h.
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