Most of our common pasture and hayfield grasses such as orchardgrass, bluegrass, fescue, ryegrass, festulolium, brome and timothy, to name a few, are cool season forage species. When summer temperatures of 80 degrees and higher arrive, these species do not thrive and their growth rates and productivity declines significantly. In pasture management we term this the summer slump. For this reason, if livestock producers need extra forage to either harvest as stored forage or to provide additional grazing, they may want to consider planting a warm season summer annual. Warm season annuals like warm to hot temperatures and can produce high yields during the summer period when cool season forages are slumping.
Recently Mark Sulc, OSU Extension forage specialist, outlined some summer annual forage options in the OSU Extension Beef Cattle Letter and I am excerpting some of his planting options and comments in this column.
Corn Silage: For anyone considering forages for silage, corn should be the first choice because of its high yields and energy content. Corn can be planted as late as mid- to late June for silage production; however, it does carry increased risk especially if dry weather develops. Nevertheless, June planted corn with adequate rainfall can produce more forage with greater feeding value than other summer annual grasses. If forage is needed before the ear is formed, corn can be green chopped. Even without the ear, the feeding value of corn is at least equal to that of the other summer annual grasses and yields are likely to be higher.
Summer Annual Grasses: Sudangrass, sorghum x sudangrass hybrids, pearl millet, and forage sorghum grow rapidly in summer. When managed properly, these grasses can provide good quality forage. All these species can be planted up to mid-July and will produce 3.5 to 5 tons of dry matter per acre assuming sufficient moisture is present for emergence and growth. Pearl millet is essentially free of prussic acid poisoning potential, while the sorghum species have the potential for prussic acid poisoning which varies by species. Nitrate toxicity is possible with all summer annual grasses. More information about the establishment and management of these species is available in the Ohio Agronomy Guide, on pages 11—114. That publication is available as a pdf file at: http://go.osu.edu/OHagronomyguide .
Teff: is a relatively new warm-season grass option that can be used for hay, silage, or pasture. In our test plots it produced about 3 to 4 tons of dry matter per acre from 3 cuttings. It can tolerate drought-stressed as well as waterlogged soil conditions. For more details on managing this forage, see an excellent factsheet from Cornell University found at: http://tiny.cc/CornellTeffInfo.
Soybean: can be grown for forage, but it is extremely difficult to make good soybean hay and ensiling soybean also has problems. The high concentration of fat (about 10%) inhibits bacteria in the silage and fermentation is slow and often incomplete. The best approach to using soybeans as a forage is to mix them with corn plants during silo filling. A mixture of 1 part or more of corn to 1 part soybean works well. In large diameter upright silos, adequate mixing usually occurs when one load of corn is unloaded followed by one load of soybeans. In smaller diameter upright silos one-half load of soybeans followed by one-half to a full load of corn will usually result in adequate mixing. For silo bags, mixing is difficult. The ratio of corn to soybeans should be increased and the amount of soybeans put in the silo at one time should be small. The best solution would be to chop about one-fourth to one-half load of soybeans and fill the rest of the wagon with corn. Use of herbicide-treated soybeans for forage or hay is allowed for only a few herbicides, so check chemical labels before using herbicides on soybeans to be used for forage.