Bacterial Community Diversity in Soil Under two Tillage Practices as Determined by Pyrosequencing
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The ability of soil to provide ecosystem services is dependent on microbial diversity, with 80–90 % of the processes in soil being mediated by microbes. There still exists a knowledge gap in the types of microorganisms present in soil and how soil management affects them. However, identification of microorganisms is severely limited by classical culturing techniques that have been traditionally used in laboratories. Metagenomic approaches are increasingly becoming common, with current high-throughput sequencing approaches allowing for more in-depth analysis. We conducted a preliminary analysis of bacterial diversity in soils from the longest continuously maintained no-till (NT) plots in the world (52 years) and in adjacent plow-till (PT) plots in Ohio, USA managed similarly except for tillage. Bacterial diversity was determined using a culture-independent approach of high-throughput pyrosequencing of the 16S rRNA gene. Proteobacteria and Acidobacteria were predominant in both samples but the NT soil had a higher number of reads, bacterial richness, and five unique phyla. Four unique phyla were observed in PT and 99 % of the community had relative abundance of <1 %. Plowing and secondary tillage tend to homogenize the soil and reduces the unique (i.e., diverse) microenvironments where microbial populations can reside. We conclude that tillage leads to fewer dominant species being present in soil and that these species contribute to a higher percentage of the total community.
KeywordsPyrosequencing Soil community analysis 16S rRNA gene Long-term tillage Plow tillage No-tillage
The authors thank Victor M. Valentin for his help in sample collection, STAR Lab (Wooster) for analysis of soil properties, and Yoon-Seong (ChunLab, Inc.) for his assistance in bioinformatics. Funding for this study was provided by the USDA-NIFA, Award No. 2011-68002-30190 “Cropping Systems Coordinated Agricultural Project (CAP): Climate Change, Mitigation, and Adaptation in Corn-based Cropping Systems”.
Conflict of Interest
The authors declare that there are no conflicts of interest.
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