Effect of Subsurface and Surface Tillage on Structure and Permeability of Solonetzic and Chernozemic Soils.

Title (Oral Presentation): Effect of Subsurface and Surface Tillage on Structure and Permeability of Solonetzic and Chernozemic Soils

Authors: Raul Avila¹, Tom King¹, Jeff Schoenau¹, Bing Si¹ and Mike Grevers¹

¹Department of Soil Science, University of Saskatchewan, Saskatoon, SK CANADA S7N 5A8

Abstract: Excessive compaction in wet Chernozemic (U.S.: Aridic Boroll) soils induced by field traffic may adversely alter soil structure, inhibit soil aeration, restrict water infiltration and nutrient uptake, and inhibit plant root development, affecting plant yields. Subsoiling at depth may be a solution to improve soil physical conditions in compacted Chernozemic and naturally dense Solonetzic (sodium affected) subsoils. On the other hand, vertical tillage implements may be used to manage residue and alter soil physical conditions mainly at the soil surface. The objective of this study was to evaluate the effect of subsurface and surface tillage on soil physical properties and plant yield in wheel traffic compacted and non-compacted Chernozemic and Solonetzic soils in southern Saskatchewan, Canada. Subsoiling increased air permeability. In the Chernozemic soil, the subsoiling treatments increased air permeability to 2.87E^-6 m sec^-1 from 4.5E^-7 m sec^-1. In the Solonetzic soil, subsoiling decreased soil strength to 1579 KPa compared to 2376 KPa in the non-subsoiled treatment. Vertical tillage in the Chernozemic soil tended to decrease water infiltration and air permeability compared to the un-tilled soil which may be explained by an increase in the number of fine pores. Crop yields (wheat, canola) were not significantly affected by tillage except for sub-soiling of the compacted Solonetzic soil, which resulted in a seed yield increase of canola of ~ 1000 kg ha^-1. Wheat yields were not significantly affected by vertical tillage treatment. Overall, subsoiling of the compacted soils tended to have a greater influence on soil physical properties than vertical tillage.