Effects of tillage and crop rotation on microbial diversity in wheat rhizosphere
The effects of tillage and preceding crops in a legume-based rotation on the diversity of microbial communities in the rhizosphere of wheat were assessed in a field experiment. Zero tillage and conventional tillage systems were compared and the crops that preceded wheat in the rotation were field peas, red clover green manure, summer fallow and wheat. Biolog’rM media were used to evaluate microbial functional diversity by assessing the numbers and types of substrates that could be utilized by the soil bacterial community. There were no significant differences in microbial diversity between treatments prior to seeding. In the rhizosphere, microbial diversity was significantly greater under zero tillage than under conventional tillage at four-leaf stage, but the difference was not significant at flag-leaf stage. In the bulk soil, conventional tillage resulted in significantly greater microbial diversity at four-leaf stage, but zero tillage had significantly greater diversity at flag-leaf stage. Preceding crops did not significantly affect microbial diversity at any sampling time. Principal component analysis revealed that two components accounted for 71-97% of the variation in microbial diversity, with one component attributable to differences in the ability of microbes to utilize amines/amides, amino acids and carboxyllic acids. and the other component due to differential utilization of carbohydrates, polymers and other substrates.
The following license files are associated with this item: