Sheep grazing wheat summer fallow and the impact on soil nitrogen, moisture, and crop yield

Authors: SNYDER, ERIN - MONTANA STATE UNIVERSITY; GOOSEY, HAYES - MONTANA STATE UNIVERSITY; HATFIELD, PATRICK - MONTANA STATE UNIVERSITY; Lenssen, Andrew

Submitted to: Midwestern Section of the American Society of Animal Science
Publication Type: Proceedings
Publication Acceptance Date: 6/15/2007
Publication Date: 6/22/2007
Citation: Snyder, E., Goosey, H., Hatfield, P., Lenssen, A.W. 2007. Sheep grazing wheat summer fallow and the impact on soil nitrogen, moisture, and crop yield. [abstract] Midwestern Section of the American Society of Animal Science. [Abstract] ASAS Western Meeting Boise, Idaho, June 20–22, 2007. Abstract no. 60, p.168.

Interpretive Summary: Integrating livestock into farming and natural resource management may have the added benefit of enhancing rural development through low-capital entrepreneurial opportunities based as much on the concept of landscape management as on traditional meat and wool production. The largest constraint to entering a land-based agricultural industry is often the purchase of land. Integrating livestock into farming systems for residue, weed, and insect control may allow entry for new and existing entrepreneurs by generating income through residue harvest and landscape management. Success in this arena will require that operators view themselves as vegetation managers as much as meat and fiber producers and develop an expanded view of the resources they need. Our study investigates the influence of three weed management methods in two annual crop rotations on grain yield, and water and nitrogen use and use efficiencies. Crop rotations are fallow-spring wheat and fallow-winter wheat; weed management methods are conventional tillage with a field cultivator, zero tillage chemical fallow, and sheep grazing. Each rotational component, wheat and fallow, is present each year. The experimental site is near Bozeman, Montana. After the completion of one cycle, two field years, grain yield of winter and spring wheat did not vary by weed management method, and averaged 50.6 and 45 bushels per acre, respectively. Likewise, soil water and nitrate-nitrogen concentrations did not vary among weed management methods. Results from the first two-year cycle of this experiment document that sheep grazing summer fallow for weed management has not changed productivity, water, or nitrogen use by spring or winter wheat.

Technical Abstract: When incorporating targeted grazing into farming systems, livestock producers and farm operators need assurance that the benefits from their activities are worth their investments. Cropping systems were once integrated with livestock production: livestock gained forage value from crop aftermath, crops were growth to sustain livestock, and livestock were used as implements to produce crops. Today, few cropping systems include livestock. Sheep and goats are traditionally produced on rangelands or pasture forages and supplemented during winter with harvested feeds. Our study investigates the influence of three weed management methods in two annual crop rotations on grain yield, and water and nitrogen use and use efficiencies. Crop rotations are fallow-spring wheat and fallow-winter wheat; weed management methods are conventional tillage with a field cultivator, zero tillage chemical fallow, and sheep grazing. Each rotational component, wheat and fallow, is present each year. The experimental site is near Bozeman, Montana. After the completion of one cycle, two field years, grain yield of winter and spring wheat did not vary by weed management method, and averaged about 3500 and 3000 kg ha-1, respectively. Likewise, soil water and nitrate-nitrogen concentrations did not vary among weed management methods. Results from the first two-year cycle of this experiment document that sheep grazing summer fallow for weed management has not changed productivity, water, or nitrogen use by spring or winter wheat.