The population of rhizosphere microorganisms under oat(Avena sativa) and common vetch(Vicia sativa) was studied in different planting modes.The populations of rhizosphere bacteria,fungi and actinomycetes increased under oat through the jointing stage to the flowering stage then gradually decreased with oat growth.The population of rhizosphere bacteria under oat mixed with common vetch was significantly greater than that under oat monoculture(P<0.05) at different growth stages of oat.At harvest,the populatio...