Effects of eugenol on soil microbes in wheat fababean intercropping and monocropping systems

In order to provide theoretical basis for the regulation of intercropping system of existed allelochemicals, effects of eugenol, a kind of wheat rootexudate, on microbial population and diversity of intercropped and monocropped wheat fababean systems under 75% field capacity condition were investigated by a pot experiment. Results showed that as a whole, soil microbial diversities decreased, fungi and actinomycetes population decreased, and bacteria population increased in wheatfaba bean intercropping and monocropping systems. Among the three cropping patterns, compared with no eugenol application, eugenol treatments displayed inhibitory effects on the amounts of soil fungi and actinomycetes, which decreased by 21.95%-98.42% and 13.33%-92.82%, respectively. Bacterial population of sole wheat decreased by -118.63%-90.73% than intercropping treatments, while that of sole bean increased by -56.39%-76.76%. The relative amount of actinomycetes of the microbial population declined by -4.42%-4.32%, while the ratio of bacterial population increased by -4.36%-4.32%. Compared with wheat and bean monoculture, wheatbean intercropping could reduce soil microbial diversity index, in which soil microbial diversity index decreased by 15%-26.98% and -45.45%-6.67%, respectively. The microbial diversity index of monoculture with eugenol treatment declined.