Abstract: The metabolic function diversity of maize rhizosphere microorganisms in maize monoculture system and maize/sugarcane intercropping system was examined in Yuanjiang and Longchuan counties of Yunnan Province by Biolog-ECO techniques. The results showed that the average well color development (AWCD) of microbial communities in rhizosphere soils in intercropping maize increased by 28.50% and 42.32% than that in monoculture system at both sites, respectively. The Shannon index of rhizosphere microorganisms in intercropping maize system was higher than that in monoculture system at both sites. The utilization rate of 22 carbon sources by rhizosphere microorganisms increased, while the utilization rate of other two carbon sources decreased in intercropping system than in monoculturesystem. However, seven kinds of carbon sources had no consistent pattern in utilization rate between intercropping and monoculture systems in both sites. Intercropping increased the carbon source utilization rate than monocropping, but with geographic differences. The results of principal component analysis (PCA) showed that the rhizosphere microbial community composition and metabolic function were different between intercropping and monoculture systems. In conclusion, diversity, activities, and metabolic function of soil rhizosphere microbial community were higher in the maize/sugarcane intercropping system than that in maize monoculture. The results will provide a theoretical basis for examining the effects of maize/sugarcane intercropping on the activity of rhizosphere microbial community.

Key words: carbon starvation, soluble sugar, plant organ, starch, non-structural carbohydrate