Whether it's too much rain or perfectly timed rain, many fields are flooded or too wet to continue planting in many parts of Iowa. Delayed and preventative planting crop insurance dates are fast approaching with an unfavorable weather forecast. Decisions surrounding your delayed and prevented planting provision need to involve a conversation with your crop insurance provider. There is a nice article available on the Ag Decision Maker website that talks about the insurance provision implications. Additionally, there is are articles addressing Late Corn Planting Options and Late Soybean Planting Options; these articles discuss late planted yield potential. Each choice has practical and economic implications; approach this decision with caution and armed with good information.
If prevented planting is taken, it is highly recommended to plant a cover crop or an emergency forage crop rather than letting the field be fallow through the summer. Please note; under prevented planted provisions a cover crop or emergency forage CANNOT be grazed or harvested for forage until after September 1 (updated from November 1 based on press release from USDA RMA) and cannot ever be harvested for grain without reduction to prevent plant coverage payment. Please discuss this with your crop insurance provider.
Cover Crop Options and Considerations
Winter Cereals (Rye, Wheat, Triticale) can be planted as early as August with good success of winter survival and high forage yield potential in spring. Minimum seeding rate of 45 pounds/acre for cover, but twice that to maximize a forage harvest in spring. Best success when planting is followed by rainfall. Drill seeding is more uniform than broadcast or aerial seeding. Winter cereal rye is generally the most economical.
Spring Cereals (Oats, Wheat, Barley) can be planted anytime before September 15. When planted early they will likely produce a seed head that will shatter causing some reseeding.
Soybean can be planted as a prevent plant cover crop option. It is recommended to plant in rows narrower than 15-inches or broadcast seed. Row crop planters can be used by planting at a ½ seeding rate in the normal row direction followed by planting perpendicular, at an angle, or offset from the original row. Use a seeding rate of 60,000 to 80,000 seeds/acre, maybe slightly higher if broadcast seeding. Narrower rows and lower seeding rate will support branching to achieve canopy closure more quickly for weed competition. For consideration, soybean might be a viable option to use treated seed that has already been purchased.
Corn can be planted as a prevent plant cover crop option. This is not a preferred option because of challenges associated with fall residue management, future volunteer corn, and seed cost. If using corn as a cover crop on prevented plant acres, use a seeding rate of 60,000 to 80,000 and narrow row spacing as mentioned above in the soybean considerations. This will promote faster canopy closure and reduce the number and amount of viable seeds produced.
Brassicas (Turnips, Kale, Forage Rape, Radishes) should be planted from late July into August for best biomass. If planted in June, most of these will likely ‘bolt’ and produce seed by fall. They can be planted with a cereal grain such as oats, triticale or rye. The brassicas will winterkill, but they are highly frost tolerant and will remain a good grazing forage well into November.
Legumes (Crimson Clover, Berseem Clover, Field Pea, Hairy Vetch, Common Vetch) are slower to establish and more expensive than other cover crop options. Seeding should occur in August to ensure adequate growth that would lead to higher overwintering success.
This article has been adapted from two previous ICM News articles written by Stephen Barnhart; Prevented Planting and Cover Crop Considerations, June 2013 and Forage and Cover Crop Considerations for Delayed Planting and Flooded Sites, June 2008.
Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Integrated Crop Management News, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on May 31, 2019. The information contained within may not be the most current and accurate depending on when it is accessed.