Non-Peer ReviewedConversion from intensive tillage (IT) to no-till (NT) management creates an altered
habitat for soil microorganisms. We utilized four long-term tillage experiments in
Saskatchewan and Alberta to compare NT and IT microbial communities. Microbial
abundance increased at the soil surface (0- to 5-cm depth) in NT vs. IT soils. Differences
were much less pronounced or negligible at the 5- to 10-cm and 10- to 15-cm depths.
Despite increased biomass of fungi and bacteria in NT surface soils no significant shift in
the relative proportion of individual groups of organisms within the community was
observed. Similarly, analysis of bacterial DNA fingerprints indicated that while microbial
community clusters in the 0- to 5-cm depth increment were different than those at greater
depth, there was no significant effect of tillage. Our results demonstrate that depth was a
stronger determinant of microbial community structure than tillage management