Minnesota small grain crops can provide excellent-quality forage, although the growth stage at cutting impacts both quality and quantity.
Impact of growth stage at harvest
University of Minnesota research found that quality, crude protein and in-vitro digestible dry matter is highest at the boot stage, when the forage yield is 38 to 42 percent of that at the dough stage.
This is conveyed in Tables 1 through 3, which shows spring-seeded small grain species grown in Minnesota. Grains were fertilized with 75 pounds per acre of added nitrogen and weren’t planted as companion crops.
Removing small grains at the boot stage allows for double-cropping with another annual, such as sudangrass, rape or ryegrass. In the study, double-cropping barley and sudangrass produced 4.9 tons of dry matter per acre when barley was harvested at the boot stage (1.7 tons from barley) followed by grazing Trudan sudangrass for 41 days (mid-August through September). Double-cropping offers reasonable yields of high-quality forage, but input costs can be higher.
Table 1: Per-acre yields of spring small grain species
| Species | Boot growth stage | Milk growth stage | Dough growth stage | Average growth stage |
|---|---|---|---|---|
| Wheat | 1.45 tons | 2.74 tons | 3.78 tons | 2.44 tons |
| Triticale | 1.71 tons | 2.96 tons | 4.05 tons | 2.64 tons |
| Oats | 1.56 tons | 3.01 tons | 4.09 tons | 2.64 tons |
| Barley | 1.71 tons | 3.18 tons | 4.39 tons | 2.81 tons |
Table 2: Crude protein of spring small grain species
| Species | Boot growth stage | Milk growth stage | Dough growth stage | Average growth stage |
|---|---|---|---|---|
| Wheat | 22.8% | 15.7% | 11.9% | 16.8% |
| Triticale | 22.2% | 15.2% | 11.6% | 16.3% |
| Oats | 20.5% | 14.6% | 11.5% | 15.7% |
| Barley | 23.4% | 15.7% | 12.3% | 17.1% |
Table 3: Dry matter digestibility of spring small grain species
| Species | Boot growth stage | Milk growth stage | Dough growth stage | Average growth stage |
|---|---|---|---|---|
| Wheat | 76.2% | 63.3% | 58.8% | 66.1% |
| Triticale | 79.6% | 66.4% | 61.3% | 69.1% |
| Oats | 77.6% | 61.5% | 56.8% | 65.3% |
| Barley | 81.3% | 68.5% | 64.4% | 71.4% |
Harvesting oats for silage
Many farmers grow oats as a companion crop with forage seedlings. Silage made from these oats can supply good quality feed for livestock. Oat silage quality is influenced by the stage of maturity at harvest and the material’s moisture level.
Harvesting oats early for hay or silage improves the legume establishment process. This is because, during the seeding year, oats compete with the legume for moisture and essential nutrients.
Early harvest also prevents lodging and smothering problems later in the growing season. The silage harvest process eliminates problems related to straw removal and volunteer oats from shattered seed heads.
Strategies for success
You’ll get the best oat silage if you:
- Select a proper variety.
- Use a high-fertility program.
- Cut at late milk or early dough stage.
- Wilt if cut early to reduce moisture.
- Chop short.
- Pack well and cover in silo.
When growing oats for silage, select a variety with good lodging resistance and early maturity. The taller, later-maturing varieties can produce the best quality silage, but you must harvest them early to prevent excessive damage to the underseeded legumes.
Seed oats at 1.5 to 2 bushels per acre with the various legume underseedings at the following rates:
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Alfalfa: 7 pounds per acre, 32 plants per square foot.
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Birdsfoot trefoil: 4 pounds per acre, 34 plants per square foot.
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Red clover: 5 pounds per acre, 30 plants per square foot.
Table 4: Oat harvest moisture, protein content and total dry matter
| Oat growth stage | Harvest moisture | Protein | Dry matter |
|---|---|---|---|
| Boot | 87% | 17% | 1 ton (per acre) |
| Heading | 83% | 15% | 2 tons |
| Flowering | 78% | 12% | 2 tons |
| Milk | 72% | 12% | 2 tons |
| Dough | 67% | 8% | 3 tons |
| Seed | 59% | 8% | 3 tons |
Protein content
Protein content (dry weight basis) of oat silage varies from 6 percent at the dough stage to nearly 16 percent at the early boot stage. Protein and dry matter yields for oats harvested for silage at various growth stages in Minnesota depend on maturity.
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Early heading and flowering harvests: High in protein, low in fiber and very high in moisture. Wilt the crop to less than 70 percent moisture or add preservatives. Such silage is low in energy value, but high in protein.
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Late milk or early dough stage harvests: Lower in protein and moisture, but higher in fiber. Moisture may still be too high to store in conventional silos, so wilt silage to less than 70 percent or add preservatives.
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Mid-dough stage cuttings: High in fiber and energy value, but low in protein. The field may be yellowing due to maturity by this stage, and direct cutting is possible. You don’t need preservatives to maintain silage quality.
Plan the fertility program based on soil test and yield level for the legume and oat crop because nutrient requirements in the two crops aren’t the same. Nitrogen, phosphorus and potassium are the key elements to consider. Liming may be necessary to adjust the pH, so the legume can properly grow.
Oat silage yields vary depending on weather, variety, planting date, growth stage at cutting and soil fertility. However, 10 tons of silage have been harvested from fields capable of producing about 70 bushels of grain. A ratio of 1 ton of silage per 7 to 8 bushels of grain is routinely used to estimate silage yield.
Reviewed in 2018