The effect of tillage practices and soil compaction on the physical properties and productivity of a clay soil

This study investigates the effects of tillage and zero tillage practices on soil physical properties and crop growth. The research plot was on an Osborne clay (Rego Humic gleysol) near Brunkild, Manitoba which had been zero tilled for the previous 8 years. Tillage treatments were initiated by cultivating the zero tilled field in the fall of 1990. All plots were seeded with hard red spring wheat (Triticum aestivum cv. Katepwa) in the spring of 1991 and barley (Hordeum vulgare cv. Argyle) in the spring of 1992. The four soil physical properties (oxygen diffusion rate, soil temperature, soil water content, and soil strength) which directly affect plant growth were monitored at various times during the growing season. Crop tillering, above ground dry matter production, root density and final yield were determined. In 1992 the effects of wheel traffic on soil strength, aeration, moisture and above ground crop growth were also monitored.; Soil temperature in the upper 20.0 cm was not affected by tillage treatment throughout the 1991 and 1992 growing seasons. Oxygen diffusion rate was similar for zero tilled and conventionally tilled treatments. However, the oxygen diffusion rate was below the critical level of 0.2 {dollar}rmmu gcdot cmsp{lcub}-2{rcub}cdot minsp{lcub}-1{rcub}{dollar} at a depth of 10.0 cm or greater in both 1991 and 1992. Conventionally tilled soil had higher gravimetric water contents in the upper 10.0 cm at the time of seeding than did zero tilled soils in the 1992 growing season. Soil strength did not differ consistently between tillage treatments. However, zero tilled soils tended to have higher mean soil strengths in the upper 10.0 cm in 1991.; Plant data obtained indicated that cereal grain production in 1991 or 1992 was not affected by zero and conventionally tilled treatments. (Abstract shortened by UMI.)...