Submitted to: American Society of Agronomy
Publication Type: Book / Chapter
Publication Acceptance Date: 8/22/2001
Publication Date: 6/1/2006
Citation: Cochran, V.L., Danielson, J., Kolberg, R.L., Miller, P., Padbury, G. 2006. Dryland Cropping in the Canadian Prairies and the U.S. Northern Great Plains. Dryland Agriculture. Second Edition. Madison, Wisconsin, USA: American Society of Agronomy, Inc., Crop Science Society of America, Inc., Soil Science Society of America, Inc. p. 293-340.
Interpretive Summary: Precipitation in the Canadian Prairies and northern Great Plains increases from west to east, while average temperatures and length of growing season decrease from south to north. Drier and colder climates reduce the options for the types of crops grown. The traditional management practices used in the western northern Great Plains is wheat alternating with summer fallow using clean tillage methods. There has been an increase in reduced or no-tillage during the last few decades. This has increased the efficiency of water use by crops and allowed growers to increase cropping intensity and diversity by substituting crops in place of fallow. Increasing crop diversity offers opportunity to break weed, insect and disease cycles. Growing alternate crops also has the potential to reduce grower dependence on wheat as the main crop. However, there has been a greater shift to legumes and oilseed crops in place of fallow in the Canadian Prairies than in the northern Great Plains. This is partly due to the greater efficiency in water use by crops in cooler climates and partly due to the U.S. Government programs available to U.S. growers. Commodity prices have declined during the last few years, and the percentage of farmer income from government programs has increased dramatically. There has been a continued exodus from the rural northern Great Plains accompanied by fewer but larger farms using bigger equipment. Adopting reduced or no-tillage practices have allowed growers to farm more land with the same equipment, which has also contributed to the outward migration from rural areas.
Technical Abstract: The Canadian Prairies and the northern Great plains have a continental climate with annual precipitation ranging from <300 mm in the west to >800 mm in the east. Temperature and evapotranspiration decreases from south to north. Wheat alternating with clean tilled fallow was practiced over much of both regions, but is being replaced with reduced and no-tillage practices that conserve water. This has promoted an increase in cropping intensity and diversity. Increasing crop diversity breaks weed, disease, and insect life cycles, which reduce the dependence on chemical control. Oilseed and pulse crops now account for over 30% of cropped land in the Canadian Prairies, which is about equal to that in fallow. Adoption of these crops has been slower in the northern Great Plains. This is partly due to greater water stress in the warmer climates and partly due to U.S government programs available to the U.S growers, which tend to encourage growing wheat over non-traditional crops. Availability of large equipment, agricultural chemicals and reduced tillage practices has allowed growers to farm more land. This coupled with low commodity prices has encouraged some farmers to expand while others have gone out of business. This has led to a continued exodus from much of the dryland areas of the northern Great Plains. The greatest out migration has occurred in the driest parts of the Great Plains unless irrigation was available. However, irrigation in the northern Great Plains has declined by almost 4% since 1996.