Agronomy Library > Annual Weeds

Crop Rotation Research
Author: Murray McLelland
Date Created: February 26, 2002
Last Reviewed: January 21, 2009
Summary This publication summarizes some of the crop rotation research that is being carried out in western Canada over last 10 years. According to this paper, the break-even point for profitably extending the years of cropping in a rotation is when stubble gives a 70% yield of the summerfallow yield. The other highlights of this paper are: - At Swift Current on a Brown Clay loam chernozem, continuous wheat, properly fertilized, yielded about 75% as much as fertilized wheat grown after fallow, the 12 year averages being 1455 kg/ha (21.5 bu/ac) and 1860 kg/ha (27.6bu/ac) respectively. - In the Dark Brown soils of Saskatchewan, a twenty year study at the Scott Research station compared wheat-fallow rotation with continuous cropping. The yield of wheat from continuous cropping was 84% of the yield of wheat after fallow from 1981-1985 with yields averaging over 2 t/ha(30 bu/ac). This yield exceeds the 70% breakeven point. - Another factor was thought to be the influence of continuous wheat crops on soil productivity. Leaf diseases on continuous cropping were no more severe than for the wheat grown on fallow. It was noted that while the potential does exist for increased disease losses where continuous monoculture is practiced, the good general disease resistance of red spring wheat cultivars and the dry climatic conditions of the brown and dark brown soil zones kept such losses to a minimum in the study. - Yield of wheat grown after flax in Flax-Wheat-Barley rotations averaged 20 - 32% higher (300 - 620 kg/ha more) than the yield of wheat following wheat in monoculture rotations at Indian Head.  Document Source: Canada Grains Council's Complete Guide to Wheat Management