Effect of minimum tillage and crop sequence on crop yield and quality under irrigation in a southern Alberta clay loam soil

Abstract

Productivity losses due to soil erosion are less obvious in irrigated land, so farmers in southern Alberta have been slow to adopt conservation tillage. Moreover, local information on the effects of the tillage systems in an irrigated (sprinkler) soil on the performance and yield of cereal and row crops is limited. This study examined the effect of tillage and crop sequence on yield of soft white spring wheat ( Triticum aestivum L.), grain legumes (pinto bean, Phaseolus vulgaris L., or pea, Pisum sativum L.) and sugar beet ( Beta vulgaris L.). Two tillage systems (conventional tillage (CT) and minimum tillage (MT)) and two crop sequences (Sequence 1: spring wheat, sugar beet, spring wheat, legumes, and Sequence 2: spring wheat, spring wheat, legumes, sugar beet) were evaluated in a split–split plot design. After the start up year (1994), one cycle of the two 4-year crop sequences was completed (1995–1998) with all the crops of a sequence present each year. Wheat yield varied between 4335 and 6309 kg ha −1, legume yield between 459 and 2866 kg ha −1, and sugar beet yield between 53.1 and 66.3 Mg ha −1. All three crop yields were not significantly affected by tillage system over the study period. While there were no significant differences in soft white spring wheat and annual legume yield between the two crop sequences studied, sugar beet yield was significantly higher in Sequence 2 in 2 of the 4 years. The crop sequence generally favored whatever crop follows legumes. Thus, soft white spring wheat yield benefited from Sequence 1 while Sequence 2 favored sugar beet yield. This study demonstrates that implementation of MT in irrigated farmland in southern Alberta is highly feasible for long-term irrigated agricultural production, and supports the importance of including annual legumes in the crop rotation.