Pyrosequencing technology reveals the impact of different manure doses on the bacterial community in apple rhizosphere soil

We used DNA-based pyrosequencing to characterize the bacterial community structure of apple rhizosphere soil with different manure ratios. Five percentages of manure (5%, 10%, 15%, 20% and 25%) were examined. More than 10,000 valid reads were obtained for each replicate, and the community was composed of three dominant groups (Proteobacteria, Actinobacteria and Acidobacteria). Principal component analyses revealed that the rhizosphere samples were significantly different among the low manure treatments (control, 5% manure), the 10% manure treatment and the high manure treatments (15%, 20%, 25%). Four Bacillus species and 54 uncultured species showed a decreasing trend with increasing manure ratios. Soil treated with 10% manure showed the highest urease activity, a relatively higher saccharase activity, and the highest plant growth. Our experimental results suggested that although greater manure content leads to higher soil organic matter content, the 10% manure treatment resulted in significantly higher soil enzyme activity and a more diverse bacterial community composition. (C) 2014 Elsevier B.V. All rights reserved.