By Jerry Lindquist, Extension Grazing Educator
Annual cover crop mixtures can make very nutritious and economical grazing crops for spring, summer, fall and early winter grazing in Michigan. Fall grazing is especially beneficial as it fills the gap as pasture grasses become dormant. Mixes of four or more plant species all planted together at the same time and same depth at a seeding rate total of 28-40 pounds per acre can be economical and nutritious for fall grazing livestock and are especially good for finishing grass-fed beef cattle.
These same mixes also tend to be soil improvers, suppressing weed growth and mining nutrients from deep down in the subsoil and bringing them to the soil surface. With their aggressive growth, they also tend to increase soil organic matter both from the grazing animal’s manure and from the decaying plant’s leaves, stems and roots. Below are answers by Michigan State University Extension staff to common questions on the grazing of fall cover crops:
Where do fall cover crops for grazing work best in Michigan?
Following a wheat harvest, oat harvest or an idled field, you usually need 70-120 days of growth before temperatures drop into the low 20s. Thus, plantings made from late July to mid August turn out the best.
What to plant for grazing?
To provide a healthy, nutritious blend, consider a balanced mixture of brassicas, small grains, legumes and cool-season grasses.
Is weed control necessary before planting?
If rotating from a sod crop like hay or pasture, usually it is. But if seeding within 10 days of combining wheat or oats, usually it is not. The volunteer wheat or oat seed that was lost on the ground from the previous crop harvest can actually become part of the new seeding mix.
Can I plant an annual cover crop on the same field each year?
The risk of insect and disease pressure will increase if the same plants are seeded on the same sites annually.
Is it wrong to plant over 40 pounds of seed per acre?
It depends. With multispecies mixes of four or more varieties for grazing that can be no-tilled into wheat and oat stubble, we have found 40 pounds of seed per acre to be enough (remember there will be volunteer small grain growth as well). Higher planting rates cause crowding, competition, disease and lower plant growth, making the stand less efficient. If planting simple two or three way mixes into fields will not provide volunteer small grains, higher seeding rates up to or over 70 pounds per acre may be advisable.
Is fertilizer needed?
Following soil test recommendations is always advised. Usually manure or 50-60 pounds of nitrogen (N) per acre is a minimum requirement. The non-legume plants really respond to N.
Is livestock death loss a risk?
Yes. Bloat, nitrate toxicity and others are a possibility. Turning livestock in on full stomachs and providing access to a round bale of hay is good insurance to prevent these. Having oats and other grasses in the mix also reduces the risk of bloat. When these precautions are followed the risks are low.
Do grazing livestock damage the soil?
Any time fields are grazed while wet, soil compaction can be a result, especially on heavier ground. Late fall and early winter grazing is often done in wet soil conditions, and some compaction will result. Thus, the best site locations are on lighter, well-drained soils. But research studies have shown that if management pulls the grazing animals out during times of excess moisture, the benefits of fall grazing will out-weigh the compaction issue. Soil fertility and crop yields often improve after cover crop grazing.
Here is some insight on the plant species to consider for cool-season mixes seeded before Aug. 15 for grazing after Nov. 1 in Michigan.
Oats: Seed 6-12 pounds in mixes. Great for fall grazing, will stay green into December and will die out in January. May start producing seed within 65 days of planting, which may be a concern if producing grass-fed beef.
Wheat, Rye or Triticale: Seed 6-12 pounds per acre in mixes. Less fall growth than oats but will survive the winter and provide substantial spring growth. Be aware of crop insurance spring-time termination guidelines for cover crops to be eligible for insurance on the following year’s cash crop.
Annual Ryegrass: Seed 6-10 pounds per acre in mixes. Short-lived (1-2 years depending upon variety), highly nutritious grass that establishes fast in the fall and will survive most winters providing more growth in spring. Can become a serious weed in fields rotated to grains the next year if proper herbicide timing is not followed.
Turnip: Seed 2-3 pounds per acre in mixes. Need 60-90 days to mature. Leaves, stem and bulb are highly nutritious. Hold their feed quality well after a killing frost and are cold tolerant to 20 F but eventually will winterkill. Some will just produce an edible leaf and stem but no tuber. Some will re-grow after grazing.
Rape: Seed 2-4 pounds per acre in mixes. Need 45-100 days to mature. Most can be re-grazed. Produces a highly-nutritious, edible leaf and stem but no tuber. Some are cold tolerant to -5 F.
Radish: Seed 1-2 pounds per acre in mixes. Need 70-85 days to mature. Vigorous fall growth of highly nutritious leaf and tuber that livestock like and do well on. Holds nutrient value well after killing frost. Taproot hairs can penetrate compacted soil hardpans and mine nutrients from the subsoil.
Red Clover: Seed 2-4 pounds per acre in mixes. Will provide some fall growth but will be more productive the next spring for spring grazing. Can last for 2-3 years, so if rotation crops are planned the next summer, termination options have to be factored in. When given the chance to mature, will produce residual soil N that can benefit future N-loving crops.
For more information, contact MSU Extension Grazing Educator Jerry Lindquist at firstname.lastname@example.org or 231-832-6139, MSU Forage Specialist Kim Cassida at email@example.com, or Michigan State University Beef Cattle Specialist Jason Rowntree at firstname.lastname@example.org.