Abstract:With field plot experiment, this paper studied the effects of differen t nitrogen application rate (0, 90, 180 and 270 kg·hm-2) on the rhizosphe re microbial community and its diversity in wheatfaba bean intercropping ecosystem. The results indicated that the amount of rhizosphere microbes fluctuated with crop growth stages, being the highest at the flowering stage of test crops. Comparing with monocropping, intercropping significantly increased the totalamount of microbes and the numbers of bacteria, fungi and actinomyces in the rhizosphere of both wheat and faba bean, but decreased the microbial diversity in the rhizosphere of faba bean at its flowering and maturing stages. Under no nitrogen and low nitrogen application rate, a larger difference was observed in the amou nt of rhizosphere microbes between intercropping and monocropping. The promotion effect of intercropping in increasing the amount of rhizosphere microbes was more apparent at tillering and flowering stages, but declined significantly at maturing stage. With increasing nitrogen application rate, the amount of microbes in wheat rhizosphere increased first and decreased then, with the peak appeared at 180 kg N·hm-2, and the effect was more obvious on monocropped wheat than on intercropped one. Nitrogen application rate had no significant effects on the numbers of bacteria, fungi and actinomyces and the microbial diversity in faba bean rhizosphere, but decreased the total amount of microbes in the rhizospher e of intercropped faba bean. Rational nitrogen application could regulate rhizosphere microbial community effectively, and there was an obvious correlation between aboveground plant diversity and belowground microbial community.