WINTER-WHEAT PERFORMANCE IN VARIOUS CROPPING SYSTEMS IN SOUTHERN ALBERTA

A study was conducted in southern Alberta from 1984 to 1992 to determine the feasibility of growing dryland winter wheat (Triticum aestivum L.) in various systems with different crop rotations, tillage treatments and row configurations. Winter wheat was grown continuously and in 2-yr rotations with fallow, canola (Brassica campestris L.) and lentils (Lens culinaris Medic.), under conventional, minimum and zero tillage. Each phase of each rotation was grown every year. Flax (Linum usitatissimum L.) replaced lentils after 4 yr of the study. After the first year, winter wheat after fallow out-yielded that in the other three rotations in all years. Zero tillage produced significantly higher yields than either conventional or minimum tillage in 3 of 8 yr. Paired-row spacing resulted in similar winter wheat yields in 4 yr and significantly lower yields than uniform-row spacing in 3 of the 7 yr in which this was compared. Extreme drought during much of the study period, which caused some crop failures, probably provided a worst-case scenario. We suggest, however, that winter wheat production in continuously cropped management systems in rotations with canola or flax is feasible. Zero tillage enhanced production, but paired-row spacing showed no benefits under the soil and climatic conditions of this study.