It is now too risky to try to establish new perennial forage stands with the warmer summer weather coming on. We should wait until August to establish perennial stands. Meanwhile, what options can we consider for growing forage this year?
We are well past the time when cool-season species like oats, triticale, Italian ryegrass and spring barley can be planted. As we move into late May and early June, we must switch to planting warm-season species.
Corn silage is still the top choice for an annual forage in terms of overall greatest dry matter (DM) yield and nutritive value compared with the other summer annual options. Even if planted so late as to prevent grain formation, the feeding value of corn is at least equal to that of the other summer annual grasses, and forage yields are likely to be higher. However, corn silage won’t be an option for every situation, especially where forage supplies are already critically short.
Sudangrass, sorghum-sudangrass hybrids, pearl millet and forage sorghum grow rapidly in summer and yield a total of 3.5 to 5 tons of DM with acceptable nutritive value. Forage sorghum can produce up to 8 tons per acre of DM in a single cut in Ohio. For dairy cows, varieties with the brown midrib (BMR) trait should be planted, as BMR produces forage almost as good as regular corn silage (although lower in starch) with very good fiber digestibility. Variety performance data is available for Kentucky (see Annual Grass report), and for sorghum-sudan and forage sorghum in Ohio.
Soil temperatures should be at least 60 to 65ºF before planting the sorghum species. They can be planted up to late June in northern Ohio and mid-July in central and southern Ohio. For those needing additional forage as soon as possible, sudangrass and sorghum-sudangrass, including the BMR varieties, can be ready for harvest in as little as 40 days, at which time up to 2 tons per acre of DM is possible. Additional cuttings are possible thereafter.
In the fall, the sorghum species will have the danger of prussic acid poisoning potential after frost events. Pearl millet is essentially free of prussic acid poisoning potential. Nitrate toxicity is possible with all summer annual grasses, and management steps should be taken to reduce that risk under high nitrogen conditions and if the summer becomes very dry. Ensiling reduces risk of both prussic acid and nitrate poisoning.
Teff is a warm-season grass that can be used for hay, silage or pasture. Soils should be at least 60 to 65ºF before planting teff. The first crop should be ready in 40 to 50 days. It produces 3 to 4 tons per acre of DM over several cuttings and can tolerate both drought-stressed and waterlogged soils. More details on managing this forage can be found in a fact sheet from Cornell University.
Brassica species can be planted in May to early June for late summer grazing or fall grazing by cattle or sheep. These species contain high moisture content, so they should be used for grazing only. Brassicas have very low fiber and high energy and should be treated more like a concentrate than as forage in diets. For more information on brassicas for forage, see the Penn State fact sheet.
Seeding rates and mixtures
Plant high-quality seed of a known variety, which will ensure high germination rate and avoid unpleasant surprises regarding varietal identity and crop characteristics. Table 1 outlines recommended seeding rates and dates for the different annual grasses. Mixtures of summer-annual grasses and legumes, such as field peas and soybeans, are marketed by some seed dealers. The legumes can increase protein content, but only in the first harvest because they don’t regrow after cutting. Legumes increase the seed cost, so consider the benefit of including legumes versus supplementing with other protein sources.
Harvesting and grazing options
Chopping and ensiling or wet wrapping are the best mechanical harvest alternatives for most of the summer annual grasses. Wilting is often recommended; storage and harvest costs are greater, and fermentation quality can be poor with crops less than about 30% DM. Ideally, silage should be left undisturbed for at least two weeks to allow the forage to reach stable fermentation. If forage is needed sooner, consider daily green chopping of forage or wet wrapping individual bales for feeding until the silage is ready. Except for teff, dry baling the summer annual grasses is a challenge. Grazing is really the only option for the brassicas because of the high moisture content.
—Excerpts from Ohio State University Extension Buckeye Dairy News, Volume 21, Issue 3
- Extension Forage Specialist
- Department of Horticulture and Crop Science
- Ohio State University Extension
- Email Mark Sulc