With wet fields and more rain in the forecast, many producers have requested prevented planting. After prevented planting has been declared, growers have several options for managing that ground. One option is planting a cover crop on these acres.

“RMA does not have an ‘approved list’ of cover crops,” according to the USDA Risk Management Agency (RMA) Fact Sheet, Cover Crops and Crop Insurance. “For crop insurance purposes, a cover crop is a crop generally recognized by agricultural experts as agronomically sound for the area for erosion control or other purposes related to conservation or soil improvement.” Work with your local NRCS office and agriculture experts to determine which cover crop is suggested for your area.

The first question when determining what cover crop to plant is when will you be able to plant the cover crop? The next question is, do you intend the crop to be grazed, cut for silage (haylage or baleage), hayed or harvested? The answers to these questions determine if you will still qualify for a prevented planting payment. Table 1 explains cover crop planting options during the crop year and your expected prevented planting payment.

For specific questions regarding your insurance policy, contact your crop insurance agent.

Cover Crop Options

Warm-Season Annuals

Warm-season annuals thrive in warm and in some cases dry conditions, allowing them to acquire large amounts of biomass with limited inputs. This makes warm-season annuals like forage sorghum, sorghum/sudan hybrids, and millets prime options for use as a cover crop. These species can be seeded any time from now until August 1 for best results.

However, warm season grass species will lose forage value after they mature into fall. For example, as sorghum/sudan grass matures from early vegetative to flowering, the protein content will drop from 18-20% to 9-11%, respectively. Total Digestible Nutrients (TDN) follow a similar trend. Vegetative sorghum/sudangrass can provide up to 70% TDN, which can drop to 55% in fully mature plants. Many warm-season annuals follow this trend when it comes to forage quality.

Haying around the soft dough stage can produce the highest yield, but will need conditioning to ensure stems dry down. Earlier harvest will increase quality while decreasing yield. Know the maturity of the variety you choose and either delay planting to match maturity with the Sept. 1 deadline or be ready for a drop in quality.

Silage cutting may be an option for those who have access to required cutting and feeding equipment. If utilizing millets, foxtail and proso have finer stems and are more adapted for grazing and haying while pearl millet will have a higher silage potential. For more information on millet silage production, see this ISU resource Millets: Forage Management. Typically, forage sorghums will reach 80-90% of the energy value of corn silage, while sorghum/sudan hybrids can reach 65-80%. As with any silage, harvesting and packing at the right moisture is critical. Cutting at full maturity when the moisture content is below 70% is ideal. To reach this point, producers may have to wait until after a frost, increasing the risk for lodging and leaf loss. Another option may be to cut and let the plants wilt until the desired moisture content is reached, then chop. For more information see the NebGuide, Harvesting Corn and Sorghum for Silage.

Another option that requires no equipment to implement is grazing. Sudangrass varieties are better suited to multiple grazing events and have better potential for regrowth. With a September 1 grazing date, regrowth will be highly dependent on the fall weather. Cool or dry conditions could dramatically limit potential regrowth. Grazing plants while still vegetative, just before beginning to boot, will provide the greatest potential yield while preventing stress on the plant that later grazing would cause. With favorable weather, this will provide a greater potential for regrowth.

For many of our warm-season annuals the transition from vegetative to reproductive stage, for those planted in early July, would be close to the September 1 date, making grazing a prime strategy. To ensure plants are still vegetative on September 1, make sure to check out the expected maturity date of the variety you choose. Depending on the selection, planting may need to be delayed a few days to ensure a vegetative state. For more information on warm-season annuals, see the NebGuide, Summer Annual Forage Grasses.

Move animals off once plants are grazed down to a height of 6-8 inches, giving the plant enough leaf material to recover and regrow. With all sorghum species, there is a potential for high concentrations of prussic acid in new shoots or frost-damaged plant tissues. Typically sorghums have the highest potential for toxic levels of prussic acid, sorghum/sudan hybrids an intermediate potential, and sudangrass, the lowest. New leaves typically have the highest concentration of prussic acid, so hold off grazing until 24 inches tall for sorghum and 15-18 inches for sorghum/sudan and sudangrass. Additionally, heavy stocking and rotational grazing can prevent animals from regrazing new growth on plants with high prussic acid concentrations. Frozen plant tissue can also cause a release of prussic acid. Give these plants at least 7 days after a killing frost before grazing. This needs to be done every time a frost occurs as a new part of the plant may be frozen. Keep an eye out for regrowth on frosted plants. If new tillers are present, either remove cattle until the new growth reaches 15-18 inches or until 7 days after a hard frost kills the entire plant. Additional management considerations can be found in the NebGuide, Prussic Acid Poisoning.

Cool-Season Annuals

If you want to hay, cut for silage (haylage or baleage), or graze a cover crop after September 1  or are unable to plant until later in the year, cool-season cover crops may be an option. Late summer planted cool-season crops like oats and turnips are great at holding nutrient value into the late fall and winter. The biggest barrier will be weed control and proper herbicide selection for planting. Be sure to check the grazing, haying restrictions, and plant-back interval when selecting a herbicide for weed control. With optimal growth well into fall, hay and silage may be difficult to produce due to reduced drying potential during cool weather. Grazing will be the best option for use under these conditions.

A late July or early August planting will be at the beginning of the acceptable planting period for cool-season crops. Recent UNL studies have shown oat brassica mixtures to have TDN levels in the 70-80% range with losses of less than 5% into January. Crude protein of brassicas is typically about 20-25% and oats, 15-20%, with little drop in TDN level into early January. An added benefit of choosing oats and turnip or radish is that as winter-sensitive species, no control should be needed the following spring. As these species will winter kill, making next year’s input cost less as compared to using other cover crops that require chemical or mechanical termination. Depending on seed costs, other options like spring wheat or triticale may provide a similar but lower quality forage option (TDN levels of 55-65%) for less cost. For more information about cool-season forages and seeding rates, see the NebGuide, Annual Cool-Season Forages for Late-Fall or Early-Spring Double-Crop.