Grazing Sheep for Alfalfa Pest Control in the Northern Plains

Wheat and alfalfa growers in the Northern Plains face major challenges in managing pests and weeds on their farms. Arthropod pests alone cause an estimated $260 million in alfalfa damage each year across the United States. Traditional control methods come with significant drawbacks: In many areas, stricter environmental regulations have led to bans on burning, and herbicide applications can be costly and management intensive.

SARE is pleased to release a new fact sheet, Sheep Grazing to Manage Crop Residues, Insects and Weeds in Northern Plains Grain and Alfalfa Systems. This fact sheet provides strategies for farmers and educators interested in using sheep for pest control. 

A team of Montana State University (MSU) researchers have turned their attention to sheep as an alternative solution to controlling alfalfa weevil, wheat stem sawfly and other pests. In three separate on-farm studies funded by SARE, they developed recommendations for effectively using sheep for pest control. For example:

• Sheep grazing wheat stubble in the fall and spring killed 75 percent of wheat stem sawfly compared with a no-treatment con-trol (42 percent sawfly killed), tillage (40 percent killed), and burning (45 percent killed).
• On a commercial sheep operation in southwestern Montana, adult weevils were reduced in grazed plots by 35-100 percent, and larvae were reduced by 40-70 percent, depending on sampling date and study year.

This fact sheet presents results from the MSU research, and covers key details of animal selection, stocking rates, timing, economics and other issues, all according to the farmer's objectives.

Because targeted grazing is gaining prominence as a land-management tool, crop producers can usually find sheep producers in their area who provide this service. Grain farmers do not have to become sheep producers to take advantage of the strategies described in this fact sheet.

Along with effectively controlling pests, grazing also: provides an environmentally friendly alternative to herbicides and pesticides; increases soil nutrient cycling and soil carbon from sheep waste deposited across the field; provides an important tool for erosion control by allowing the grower to control the amount of remaining residue, whereas herbicides and cultivation can leave the soil completely exposed; and lowers equipment and fossil-fuel costs through reduced tillage.

Using sheep as a management tool in cropping systems also benefits the sheep producer. Sheep are traditionally grazed on rangelands or pasture forages and supplemented during winter with harvested feeds. Using sheep to graze hay and grain residue not only provides a new and valuable feed source, it can also reduce costs, and offer new business opportunities.

Interested in sustainable animal production? Visit the animal production section of SARE’s Learning Center to see our entire collection of free resources related to this topic.