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Microbial responses to wheel-traffic in conventional and no-tillage systems

Runion, G.B., Prior, S.A., Reeves, D.W., Rogers, H.H., Reicosky, D.C., Peacock, A.D., White, D.C.
Communications in soil science and plant analysis 2004 v.35 no.19-20 pp. 2891
wheel tracks, soil compaction, conventional tillage, no-tillage, coarse-textured soils, soil microorganisms, microbial activity, microbial biomass
Traffic-induced soil compaction and tillage systems can impact the productivity and sustainability of agricultural soils. The objective of this study was to assess the response of soil microbial populations to wheel-traffic in two tillage systems on a Norfolk loamy sand (Typic Kandiudults; FAO classification Luxic Ferralsols). Experimental variables were with and without traffic under conventional tillage (disk harrow twice, chisel plow, field cultivator-planter) vs. no tillage employed in a split-plot design with four replications; main plots were traffic and subplots were tillage. Soil samples were collected from 0-2 and 2-4-cm depths, sieved (2 mm), and used to assess soil-water content, microbial biomass nitrogen (N), dehydrogenase, and microbial characterization using phospholipid ester-linked fatty acid (PLFA) analysis. Traffic increased soil-water content, had little affect on microbial biomass N, and increased microbial activity (no-till plots only) likely due to increased amounts of residue. Soil-water content, microbial biomass N, PLFA estimates of microbial biomass, and microbial activity were all consistently higher in no-till compared to conventional tillage plots. Data from this study suggest that conventional tillage results in a lower, more static, possibly more mature community of microbes while the microbial community under no-till appears to be a younger, more viable growing population. Finally, these data suggest that overall soil quality, at least in the surface soil layer, is improved in agricultural systems employing no-till operations.