Prevented plant: Cover crop and forage options

Warm-season grasses include forage sorghum, sudangrass and sorghum-sudan. These warm-season grasses are more tolerant of drought and hot weather than cool-season small grains (oats, wheat, barley, triticale) and produce a large quantity of forage when carefully managed.

Depending on your current nitrogen status, a fertilizer N application may boost forage production.

Grazing and harvesting

While forage sorghum is generally ensiled, sorghum-sudans and sudangrasses can be grazed or harvested for hay. Grazing or green-chopping young plants can result in prussic acid poisoning, so it’s recommended to wait until plants are at least 18 to 20 inches tall.

When harvesting sorghum-sudan or sudangrass for hay, plants should be 3 feet tall to optimize quality and yield. In Wisconsin trials, a July 1 planting date allowed for one to two harvests and occasionally yielded as much as late-planted corn.

Japanese and pearl millets, also warm-season grasses, are managed like sorghum-sudan hybrids and sudangrasses and have a low potential for prussic acid poisoning.

If you plan to wait until Nov. 1 to harvest, warm-season grasses probably won’t be a good forage option for you. These grasses aren’t frost-tolerant and will likely winterkill and lose significant forage value by Nov. 1.

Additional guidance

• Sorghums, sudangrasses and sorghum-sudangrass hybrids for forage

• Alternate forage crops

• Forage options following alfalfa winterkill

Cereals are cool-season crops usually seeded in the early spring or fall. When seeded mid-summer, hot weather will reduce growth. Even so, cereals are relatively inexpensive, easy to establish and should still provide cover.

Like warm-season grasses, cool-season grasses may benefit from a nitrogen application. In addition, planting a cereal crop will help prevent fallow syndrome.

Spring cereals (oats, barley, spring wheat, spring triticale)

Spring cereals planted in late June or July will likely develop heads, shatter and possibly produce volunteer plants. For this reason, winter cereals may be a better option if planted before Aug. 1. Spring cereals planted in late summer should provide fall growth, but will be subject to frost and winterkill.

Winter cereals (Rye, winter wheat, winter triticale)

How you’ll use the winter cereal will determine the planting date.

If you’ll use the cereal simply as a cover crop, you can establish it anytime. It may provide some forage after Nov. 1. Because winter cereals perform similarly, the choice of which one to use will depend on cost and availability.

If your goal is to harvest a grain crop the following spring, then select winter wheat. To reduce insect and disease problems, seed the crop after Sept. 10 in southern Minnesota, but check with FSA and your crop insurance agent for seeding date requirements.

Optimum seeding dates: Winter wheat

Annual ryegrass

Annual ryegrass is also a cool-season grass that may provide some forage for November grazing if planted in mid- to late-summer. It may benefit from fertilizer nitrogen.

Annual legumes, such as berseem and crimson clovers and winter peas, are a good choice for green manure or forage when planted in early spring. Late summer establishment may provide some forage, but it may not yield enough to justify the seeding cost.

If planted after Aug. 1, nitrogen contributions from these annual legumes will be negligible. As annuals, they’re subject to frost and won’t overwinter.

Red clover and vetch are examples of perennial legumes. Because these crops overwinter, they’d need to be controlled before the spring 2014 crop.

Brassicas include forage turnips, forage rape and radishes. Plant them from late July into August to optimize forage yield and quality for a November harvest.

Turnip tops can be grazed approximately 45 days after planting. After one or two grazings, you can disc the field so beets can be grazed. Yields are generally low even though beet tops have a higher relative feed value (RFV) of 150 to 250.

While generally not used for livestock forage, this short-season annual quickly establishes, provides good cover and scavenges soil nutrients.