Flooded or hailed-out fields can still be productive this summer if planted to an annual forage crop, says Steve Barnhart, Iowa State University Extension forage agronomist.
He says the following species are among the most practical, predictable and economical. If planted by mid-July, each can produce good-quality forage for grazing or mechanical harvesting in 50-60 days.
Sudangrass – This summer annual can be used for fresh-cut forage, pasture or silage, but it’s difficult to dry thoroughly for hay. Varieties vary in height and leafiness. If planted by mid-July, you may get a second harvest or grazing. The risk of prussic acid poisoning is minimal, but avoid pasturing it when it’s severely drought-stressed or less than 12” tall, and use caution if grazing it soon after a frost.
Sorghum-sudangrass hybrids – Varieties of these summer annuals vary greatly in height, leafiness and grain yield, depending on the parent lines making up the hybrid. Prussic acid poisoning is a risk if plants or regrowth tillers are grazed or green fed when less than 24” tall or during severe drought, and use caution if grazing soon after frost, Barnhart advises.
Sudangrass and sorghum-sudangrass hybrids are better-adapted than most species to drought, high temperature and low soil pH than corn, but will yield less in seasons with cool August and September temperatures. They should be harvested at 2-3’ tall; harvesting at later maturity may increase yield but will result in very low forage quality.
Short grain sorghum-forage soybean mixture – Harvest this mixture at late vegetative or very early head stage of the sorghum. It requires fertilization for good production. It has the potential to produce the highest-quality forages among the options listed here.
Foxtail millet – Also called German, Siberian or hay millet, this grass can be planted through mid-July. The best of the millets for an emergency hay crop, it should be harvested when 1-2’ tall in the vegetative stage or 2-3’ tall with seed heads. It can become a weed if allowed to produce mature seed.
Japanese millet – This relatively coarse (stemmy) forage may produce harvestable regrowth if cut or grazed at the vegetative stage. It’s closely related to the grassy weed barnyard grass, so don’t allow seeds to form.
Hybrid pearl millet – A warm-season annual grass, it resembles sorghum-sudangrass hybrids in plant structure, but regrows somewhat slower after cutting.
Japanese, foxtail and hybrid pearl millet have been of particular interest in recent years, Barnhart notes. But he says to remember that they’re warm-season crops that perform best in warm, sunny growing seasons. They have not performed up to expectation during cool, cloudy summers.
Oats - Planted anytime in July, or even in August, as a cover crop, oats can be grazed about any time. They’ll likely head at a short height and should be cut at the late-vegetative through early milk stage. At dough stage, the stems decline greatly in feeding value. Other cereal grains, such as barley, spring wheat or spring triticale, may also fit this use, but their seed will likely more expensive and in shorter supply than for oats, says Barnhart.