Achyranthes bidentata, a Chinese traditional herb grows best under continuous cropping, Thus an experiment was con- ducted to evaluate microbial flora and enzyme activity in rhizospheric soils that have been under continuous cropping of A. bidenta- ta for two and more than twenty years. The results show that bacteria is the most dominant species of microbial flora, accounting for 62.27% and 89.46% of total microbial flora numbers in the soil under continuous cropping ofA. bidentata for two and more than twenty years. Actinomycetes is the next dominant species, accounting for 37.59% and 10.45% , while fungi is the least dominant species, accounting for only 0.15% and 0.09% of total microbial flora numbers in the soil. As the number of years of continuous cropping increases, the number and percentage of bacteria linearly increase. Further analysis on the physiological groups of microbial flora shows that A. bidentata favors growth of nitrite bacteria, denitrifiers, aerobic cellulose-decomposers and sulphate-reducers. Moreover, A. bidentata increases urease, protease and invertase activities in the soil. However, continuous cropping of A. bidentata inhibites enzyme activity, though it increases polyphen-oxidase activity in rhizospheric soils. Finally, the mechanism of adptiness of A. bidentata to continuous cropping is disscussed.
Chinese Journal of Eco-Agriculture
国家科技支撑计划项目（2006038077028）和福建省重大科技项目（2004YZ02,2004YZ022,2004YZ024）资助 致谢 福建农林大学资源与环境学院汪涵博士在酶活性测定中,河南农业大学中药材系研究生杜家方、尹文佳等在试验取样中给予大力帮助,谨表谢意!
Achyranthes bidentata, Continuous cropping, Soil, Microbial flora, Enzyme activity