Microbe Composition and Vertical Distribution Profile in Tobacco Growing Soil

The composition and vertical distribution profile of microbes in different tobacco growing soils (lean moisture soil from Xiangcheng, Henan Province and rich yellow soil from Xingshan, Hubei Province) were studied. The results showed that in these two soils, the percentages of bacteria, actino-myces and fungus were 86.63%-95.48%, 4.11%-13.15% and 1%, respectively. There was an obvious vertical distribution rule of microbial number in the ridge of tobacco field. With the exception of azotobacteria, the number of all investigated microorganisms reduced by degrees with the increase of soil depth (0-40cm). Comparing the number of microbes in the soil depth of 0-20cm with that in the depth of 20-40cm, fungus showed the biggest difference, bacteria showed the smallest. Among the microbial physiological communities, obvious difference was observed in nitrate bacteria numbers, and relatively smaller differences were observed in potassium bacteria, phosphorus bacteria and azotobacteria numbers.