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The influence of agricultural tillage practices on soil biodiversity

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Title: The influence of agricultural tillage practices on soil biodiversity
Author: Strohm, Jeff
Department: Department of Integrative Biology
Program: Integrative Biology
Advisor: Hanner, RobertHeck, Richard
Abstract: This study was the first to examine the influence of agricultural tillage practices on the entire soil ecosystem using metagenomic techniques. Four genes were chosen to investigate bacterial, fungal and protozoan diversity, while one gene was used for arthropod diversity with all being sequenced at a very high read depth per sample. Four tillage treatments were compared with a no-till treatment, using samples collected from the long term management plots in Elora, Ontario. Overall, the microbial communities of these soils were very similar (p<0.05), but some interesting differences were found with regards to the fungi. Overall, the most diverse fungal group was the Sordariomycetes ( 103±19 mean OTU richness across treatments), and no-till had a significantly lower diversity compared with the tillage treatments (86±10 OTUs; p= 3.12e-3). The fall tillage treatments were the most diverse in terms of the Sordariomycetes (113±16 OTUs), but a large proportion of this diversity were pathogenic genera. Conversely, no-till soils possessed a significantly more diverse community of Dothideomycetes (43±1 vs 29±6; p= 5.54e-5) with the majority of this diversity belonging to the Sporormiella. This genus was essentially absent from the tillage treatments, and even more interestingly, it is known as an obligate coprophilovore. However, manure has never been intentionally applied to these soils. With regards to the arthropod communities, additional mature woodlot samples suggest that even the no-till soils are in a disturbed state. Of the four tillage treatments, spring tandem disc tillage may be the most intense in terms of disturbance to the arthropod community. However, a high degree of between-replicate variability resulted in a lack of statistically significant differences for the arthropods. Overall, no-till or conservation tillage practices are recommended, but the results generated here suggest that they cannot be relied upon to solely increase soil biodiversity. Future research should focus on temporal analyses of biodiversity patterns with special attention paid to analyses that are independent of coarse taxonomic identifications.
Description: This research was conducted at the Biodiversity Institute of Ontario, Center for Biodiversity Genomics, The University of Guelph.
Date: 2015-04
Rights: Attribution-NonCommercial-NoDerivs 2.5 Canada
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Attribution-NonCommercial-NoDerivs 2.5 Canada Except where otherwise noted, this item's license is described as Attribution-NonCommercial-NoDerivs 2.5 Canada