The most cost-effective, high-forage-producing cover crop mixture for late-season grazing appears to be a seed mixture of "Pasja" turnip, oilseed radish, conventional oats and foxtail millet.
That's according to Kevin Sedivec, North Dakota State University Extension Service rangeland specialist.
Sedivec recommends a mixture of 0.75 pound of turnip, 1 pound of radish, 15 pounds of oats and 4 pounds of foxtail millet. The turnip, radish and oats provide a high-quality, low-fiber feed, while the foxtail millet provides a fiber source for proper rumen function.
"Providing a fiber-source feedstuff to ruminant livestock such as cattle and sheep is important when grazing turnips and radish," he says. "If you want to add a legume to this mixture, use a low-cost, fast-germinating type."
Legumes planted in a cocktail-type of mixture in July and August rarely produce more than 200 pounds per acre, creating a high-cost seed for little return. A good legume to plant in this type of mixture would be field or forage peas at 10 pounds per acre, according to Sedivec.
This seed mixture should cost approximately $8 to $10 per acre and produce 1.5 to 4 tons per acre, depending on location. If adding peas to the mixture, expect an additional cost of $2.50 to $3 per acre.
Seed this type of forage mixture for late-season grazing in mid to late July, and no later than early August. The mixture should receive 45 to 60 days of growth before a killing freeze to provide adequate production.
"To obtain the greatest efficiency of the grazing forage, limit feeding in the field by using a temporary, moveable electric one-strand fence to provide three to seven days of feed at a time," Sedivec says. "This technique will substantially reduce waste from trampling and increase harvest efficiency of the standing crop."
No livestock options
For producers with prevented planting acres who do not have livestock or the fence and water to use the land for grazing, seeding a cover crop still can provide a substantial value through soil-building properties and water use. This cover crop can be incorporated into the soil later to increase organic matter, fertility and water-holding capacity, and decrease ponding water.
"The beauty of growing a crop in September and October is you are removing water from the system that created the high water levels," Sedivec says.
Radishes and turnips are good cover crops because they help reduce compaction layers in a field. The leaf tissue provides an excellent source of nitrogen, while the bulbs or tubers provide a good source of simple-chain carbons. Cereal grain crops provide fair levels of nitrogen and good levels of carbon unless they are seeded too early in the season. Then nitrogen is poorer and carbon very high.
Warm-season annual crops such as foxtail millet, sudangrass, sorghum-sudangrass hybrids, proso millet and pearl millet will become high in carbon and low in nitrogen. Legumes provide high levels of nitrogen and fair levels of carbon.
In general, a cover crop should provide eight to 10 parts of carbon to one part of nitrogen for soil building. When the ratio is unbalanced, high-nitrogen plants break down quickly and reduce the potential to capture the nitrogen in the soil. High-carbon plants need nitrogen to decompose; thus, nitrogen created through the system is used to decompose the high-fiber plants.
Cover crops should be cost-effective and help reduce inputs the following year.
The crop should produce a minimum of 1,000 pounds per acre to be cost-effective.
To achieve this production level, the crop needs a minimum of 30 growing days, with 45 to 60 preferred. Sedivec recommends selecting fast-growing, low-cost forage species.
A good mixture for cover crops that help build soil and are cost-effective is a combination of forages that may include "Pasja" turnip, radish, a cereal grain crop, foxtail millet, sunflowers and a low-cost legume such as field peas. This will provide a well-balanced mixture of carbon- and nitrogen-based plants.
Including buckwheat in the mixture will add phosphorus. A mixture at the Central Grasslands Research Extension Center that has been used successfully includes
0.5 pound of "Pasja" turnip, 1 pound of radish, 15 pounds of oats, 1.5 pound of sunflowers, 4 pounds of foxtail millet and 10 pounds of field peas per acre.
This seed mixture should cost approximately $10 to $12 per acre and produce 1.5 to 4 tons of soil-building material per acre, depending on location.
Source: NDSU Extension Service