Date of this Version
Agricultural Research March 2013
For decades, farmers in Montana and the Dakotas have produced impressive yields of barley and wheat. But that bounty has come at a cost. Tilling the soil in the region’s crop-fallow production systems has robbed the soil of nutrients and organic matter and reduced crop yields. In fact, the region’s soils have lost up to 50 percent of their organic matter in the last 50 to 100 years, and scientists say that current practices are unsustainable.
Agriculture also contributes about 25 percent of the human-made carbon dioxide and 70 percent of the human-made nitrous oxide being released into the atmosphere. Tillage, crop-fallow management practices, cropping sequences, and the use of nitrogen fertilizers all play significant roles in those emission levels.
Agricultural Research Service scientists and their university partners are providing guidance to growers on ways to keep soils productive and reduce their climate change footprint by turning to some of agriculture’s most tried-and-true practices. At the ARS Agricultural Systems Research Unit in Sidney, Montana, Upendra Sainju and his colleagues have been studying how no-till systems, crop rotation, ecological (or alternative) cultural practices, nitrogen fertilization, and sheep grazing can improve soil quality, reduce greenhouse gas emissions, sustain crop yields, and reduce the amount of nitrogen polluting the air and water.
Growers have known for decades that no-till improves soil quality and that rotating crops reduces weeds, diseases, and pests. Grazing by livestock is also widely known to control weeds and pests and supply a natural fertilizer. The ARS studies in Montana and North Dakota are among the first to show how these systems are feasible alternatives that do not result in reduced yields. The research is also one of the first comprehensive efforts to examine the effects of irrigation and different crop management scenarios on greenhouse gas emissions in the northern Great Plains.