Soil Failure Crescent Radii Measurement for Draft in Tillage Study

Field clay loam and sandy loam soils were tilled with a chisel shaped tine at different tillage geometries. Soil cracks and the extent of their propagations in the front and to the sides of the tillage tool were observed and measured. These measurements provided the failure crescent radii and the soil furrow geometry used in calculating the draft during tillage. The effects of the tillage tool width, rake angle and depth in the soil on the draft were statistically Significant at the 5% level and higher in the clay loam and sandy loam soils. From the established empirical relationships between the draft and the tillage tool geometry, it was possible to recommend a tillage tool geometry which would minimise draft during tillage.