Rotation, tillage and seeder effects on winter wheat performance and soil moisture regime

Abstract

The optimum management system for winter wheat (Triticum aestivum L.) production in southern Alberta has not been adequately defined. A 9-yr (1978–1986) study was conducted to determine the effects of three rotations (continuous winter wheat, winter wheat–fallow and winter wheat–barley (Hordeum vulgare L.)–fallow), two tillage systems (conventional tillage, zero tillage) and two seeder types (hoe-drill, disc drill) on winter wheat growth, yield and water use. Continuous cropping to winter wheat was terminated after 4 yr because of a heavy downy brome (Bromus tectorum L.) infestation. Soil moisture reserves to 1.5-m depth fell to only 61% of that under the wheat–fallow rotation. Wheat grown in the wheat–barley–fallow rotation yielded on average 4% higher than that in the wheat–fallow rotation. Yields under zero tillage were significantly higher in 3 of the 9 study years, and slightly higher in 5 yr, due to better soil moisture conservation once the zero-tillage treatment was established for 2 yr. Zero tillage was most beneficial when precipitation at fall planting was less than normal. The hoe-drill provided more effective seed placement than the disc drill when surface soil conditions were dry at or soon after seeding. A management system which incorporates zero tillage (and preferably seeding with a hoe drill) into a 3-yr (wheat–barley–fallow) rotation is best suited for winter wheat production in southern Alberta. Key words: Wheat (winter), crop rotation, zero tillage, seed drill, soil moisture regime