Soybean variety Xihuang 27 was exposed to enhanced UV⁃B radiation, under field condition, and rhizo⁃sphere soil parameters including soil microorganisms, content of organic matter, total nitrogen, activities of soil urease and invertase were measured during soybean development. At branching period, flowering period and seed⁃filling period, en⁃hanced UV⁃B radiation significantly inhibited the activities of soil urease by 17�9%, 11�7% and 5�7%, respectively and invertase by 23�5%, 6�1% and 13�2%, respectively. The amount of bacteria was deereased by 40�1%, 38�2% and 26�1%, respectively and the amount of aerobic azotobacter dropped by 72�2%, 33�3% and 35�7%, respectively. The a⁃mount of actinomycete was decreased by 36�3% and 50�0% only at branching and flowering whereas the amount of fungi was significantly decreased by 59�0% only at branching. No significant inhibition was found on the content of organic matter and total nitrogen. In conclusion, enhanced UV⁃B radiation could reduce the amounts of rhizosphere soil microorganisms and soil enzyme activities.%为了研究UV⁃B辐射增强对田间大豆根际土壤相关指标的影响，在大田条件下，通过模拟UV⁃B辐射增强，对大豆根际土壤微生物数量、根际土壤有机质含量、总氮含量以及根际土壤脲酶和转化酶酶活性进行测定。结果表明，在分枝期、花期及鼓粒期，UV⁃B辐射增强使脲酶的活性分别下降17�9％、1�7％和5�7％；转化酶的活性分别下降23�5％、6�1％和13�2％；细菌的数量显著降低40�1％、38�2％和26�1％；好氧固氮菌的数量显著降低72�2％、33�3％和35�7％。放线菌的数量只在分枝期和花期显著降低36�3％和50�0％，真菌的数量只在分枝期显著降低；UV⁃B辐射增强对土壤有机质、总氮含量没有显著影响。说明UV⁃B辐射增强可对大豆根际微生物的数量及土壤酶的活性产生比较明显的抑制作用。
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