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Published August 25, 2014, 09:38 AM

Forage supply and dairy production

BROOKINGS, S.D. — In the Upper Plains, it might not be economical, or even practical, to plant another grain crop during the growing year. But it might be in the producer’s interest to consider a cover crop to increase revenues.

By: SDSU Extension Service ,

BROOKINGS, S.D. — In the Upper Plains, it might not be economical, or even practical, to plant another grain crop during the growing year. But it might be in the producer’s interest to consider a cover crop to increase revenues.

“Cover crops provide multiple benefits to the producer and the environment. The primary benefit is additional forage production from the growth of the cover crop, which can be used by the producer for on-farm uses or sold to other livestock producers,” says Karla Hernandez, South Dakota State University Extension forages field specialist.

Environmentally, Hernandez says cover crops offer benefits, including improved soil quality by protecting soil from erosion and increased soil microbial activity and nutrient cycling, all while managing nitrogen and adding carbon to the soil.

Some of the main concerns for producers adding cover crops into their production scheme include: When will I plant? When and how to harvest? Which cover crops provide the best forage?

When and what to plant

Cover crops are often described in four broad categories: cool season grasses (barley and oats), cool season broadleaves (field peas and turnips), warm season grasses (millet and sorghum) and warm season broadleaves (cowpea and sunflower).

Cover crops create new opportunities to enhance rotation diversity. Hernandez explains a significant consideration in favor of cover crops is that they offer a break in the insect growth cycle, which can in turn aid with following crop yields by reducing pest influence and insecticide usage.

“The decision of what to plant is highly variable, depending upon many factors including: remaining growing season, the soil-types in the producer’s field, how adaptable the cover crop is to growth practices used by the producer including equipment available and herbicides used, and what can be obtained from the local seed provider,” Hernandez says.

“Many cover crops can work for forage supply, but the selection of which cover crop to use will depend on when you want to plant it and what is the purpose,” she says. “Usually, cover crops are planted from July through middle of September after small grain or corn silage is harvested.”

A useful guide to cover crop mixes after small grains can be found at the Natural Resources Conservation Service website: www.nrcs.usda.gov.

Forage supply

Hernandez says one way to incorporate cover crops into a grain or livestock production system is to seed winter rye after corn silage has been completed. Another possibility is incorporation of winter rye into a corn-soybean rotation following the fall harvest.

“Either option can improve soil quality, reduce soil erosion, suppress winter annual weeds and increase overall forage production for hay or silage,” she says.

In a recent study conducted by South Dakota State University, winter rye planted after corn was harvested for grain and to observe rye biomass used as a forage crop.

The trials were conducted at the Beresford and South Shore SDSU Research Farms during the 2012 to '13 winter and spring growing seasons. Rye biomass was determined in the spring before planting soybeans during both years. To learn more about this research, visit iGrow.org.

Other options

Other cover crop options producers are using across the region include seeding into a harvested corn field a 2- to 3-pounds-per-acre mix of turnips, crimson clover and annual ryegrass. Seed can be broadcasted or spread with a modified “Hi-boy” spreader. Shade-tolerant crimson clover can be sown with oats when the oats are planted, creating a “layered” field.

After the oats are harvested, the clover continues to grow and is stopped by the fall frost. Oats and field peas may be sown together for silage, diversifying the crop rotation. This can be followed with a complex cover crop blend that includes millet, sorghum, sudangrass, sunflower, buckwheat, brassicas, cowpea, soybeans and others.

Dairy production systems

Several opportunities exist to incorporate cover crops into dairy forage production systems, Hernandez says.

“According to the most recent reports, cows that are normally fed corn silage and are then put into a grazing routine of cover crops near the dairy see no substantial reduction in milk production,” she says.

She adds that cover crop mixes can be harvested and ensiled, but soil health benefits are not as strong as grazed cover crops. Producers should remember that careful planning of planting and grazing or harvest times of cover crops is essential to maximize their utilization as feedstuffs in dairy cattle diets.

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