Snow management and deep tillage for increasing crop yields on a rolling landscape

Abstract

Snow management (tall vs. conventional height stubble) and one-time deep tillage were investigated for increasing water conservation and annual crop production on a rolling soil landscape developed on glacial till in the semiarid Brown soil zone of the Canadian prairies. Tillage depths were 0, 13, 25, and 45 cm. Gleysolic soils had more soil water at time of seeding and greater 3-yr mean durum wheat (Triticum turgidum L.) grain yields than the Chernozemic soils. On the Chernozemic soils, tall (25 cm) stubble increased over-winter soil water at seeding by 15 mm compared with conventional short (14 cm) stubble. Mean 3-yr durum grain yields were 165 kg ha−1 higher with tall than short stubble although yield increases were only significant (P < 0.05) in one year. Extended rotations with tall cereal stubble are particularly attractive for cropland with a rolling topography when a significant part of the landscape is occupied by Gleysolic soils. Water conservation and grain yields for fall chiselling to 13 cm were not different than those for no fall tillage. Fall chiselling to 25 cm or subsoiling to 45 cm increased grain yields by 300 kg ha−1 in the year following tillage compared with no fall tillage. This yield increase was not related to soil water and may be due to physical disruption of an apparent tillage pan that existed between 10 and 20 cm depths. Key words: Wheat, water conservation, snow, subsoiling, rolling landscape