Abstract: By using BIOLOG technique, this paper studied the microbial carbon utilization in the rhizosphere soils of six kinds of secondary plants in Fuyun earthquake fault zone of Xinjiang. Most of the rhizosphere soils had significantly higher nutrient contents, and all of them had a higher AWCD, as compared with the control. There was a distinct difference in the AWCD among the six rhizosphere soils. Secondary plants less affected the richness but changed the dominance and evenness of the microbial carbon sources in the rhizosphere soils. The carbon sources utilization by the microorganisms in the rhizosphere soils differed with the kinds of secondary plants, and was mainly manifested in the utilization of carbohydrates, amino acids, and carboxylic acids. The appearance of secondary plants in the earthquake fault zone made the types of carbon sources utilized by the microorganisms changed from phenols to carbohydrates and carboxylic acids. In addition, the available K content in rhizosphere soils had a negative correlation with the microbial utilization of polymers (r=-0.84) and amines (r=-0.83). It was suggested that the secondary plants in the earthquake fault zone of Xinjiang could significantly enhance the capability of soil microorganisms in carbon sources utilization, and change the types of carbon sources utilized by the microorganisms. Rosa spinosissima and Achillea millefolium played the best roles in enhancing the carbon source utilization capability of soil microorganisms and in improving soil nutrient status.

Key words: earthquake fault zone, rhizosphere microorganism, functional diversity, BIOLOG, PCA