Effect of microbial fertilizer on microbial activity and microbial community diversity in the rhizosphere of wheat growing on the Loess Plateau

In this study, the effects of microbial fertilizer on microbial activity and microbial community diversity in the rhizosphere of wheat were investigated in the field conditions. Dehydrogenase activity was measured, bacterial and fungal communities were characterized by BIOLOG analysis. Soil suspensions were applied to BIOLOG ECO and FF plates and average well-color development (AWCD) and richness were calculated. The results showed that significant differences were observed in dehydrogenase activity among the tested soils, arranging from 26.14 +/- 3.30 to 48.13 +/- 17.39 TF/g.24h. For ECO plate, AWCD of MI (0.77 +/- 0.05) was higher than that of other treatments, whereas the AWCD for control (0.56 +/- 0.03) was consistently the lowest (F=8.72, p=0.0067). Meanwhile, there is a significantly difference between EP (0.16 +/- 0.03) and EP+MI (0.11 +/- 0.03) treatments in fungal community. Richness index followed the order for ECO plate: MI > EP > EP+MI > Control, and also order for FF plate as: EP>MI=Control>EP+MI. Principal component analyses (PCA) of BIOLOG data further revealed large difference in microbial diversity (metabolic diversity) from treatments soils. The data gathered from this study can provide complementary information for agricultural projects on the Loess Plateau, Northwestern China.