Wallaces Farmer

Iowa Learning Farms: Plant a cover crop or forage crop rather than letting a field be fallow over summer.

Mark Licht

June 7, 2019

4 Min Read
cover crop field
KEEP IT COVERED: Planting a cover crop or forage crop helps with weed management, prevents erosion, and keeps soil healthy and alive.

For many Iowa farmers, this spring’s rain and flooding has brought them to a decision point about crop insurance. Plant late and hope for the best, or activate prevented planting coverage and forego a primary cash crop this season. It’s a tough decision, and not without consequences no matter the choice. However, as most farmers know, even if their cash crop cannot be grown, the fields should not be left fallow for the season.

Unplanted land for just one season can set back years of weed control efforts. In addition, freshly tilled or not, bare ground will erode with additional rains and wind throughout the summer months. Losing productive and healthy topsoil due to inaction is not in the farmer’s or the environment’s best interest.

For those who intentionally — or with the wet fall of 2018, unintentionally — have cover crop residue in the fields, the remaining roots will help slow erosion. But the maximum erosion and weed control benefits will come with actively growing plants that are purposely chosen in place of the planned corn or beans. Plus, it’s better for soil microbial communities (and soil health) to have living roots in the fields.

Consider 2 options

The two viable alternatives for farmers filing prevented planting claims are to plant alternative summer forage crops or plant traditional cover crops.

Summer forage crops come with a slight disadvantage due to rules governing prevented planting payouts. Under these rules, no grain crop can be harvested in 2019, and forage crops cannot be harvested or grazed until after Nov. 1 without a reduction in the prevented planting payment. With this in mind, farmers can still plant forage crops that will provide silage and grazing, but will terminate with winter and not require special effort prior to 2020 planting.

A number of summer annuals would be good ground cover and forage options if forage is needed or can be sold. Also, some forage options have the potential to be harvested or grazed after Nov. 1 without penalty.

How about soybeans or corn?

Soybeans and corn can be considered for forage planting, but they are not the best options. If corn or soybean seed has already been purchased, it may be more economical to plant it and forego harvest. Since it is being used as a cover crop, traditional row planting is not recommended.

Broadcast or planting in overlaid perpendicular rows will increase the crop canopy and reduce weed growth during the summer. Of the two, corn is the least attractive due to the significant amount of crop residue after termination by freezes in the fall.

Other summer forage options to consider include different varieties of millets, Italian ryegrass, sorghum and soybean mixture, berseem clover, and sudangrass. All are warm-season plants that will terminate in winter, but most should be cut before going to seed to prevent volunteer growth in the 2020 cash crop.

Consulting an agronomist is a good idea to help you understand the different crops, potential interactions with ongoing herbicide programs, and advice regarding silage, grazing and dried hay needs.

Factors such as the need and storage capacity for silage and hay, drying requirements, and seed availability should also be considered. Seed for these crops may be in limited supply, so it is recommended that decisions be made as early as possible.

Cover crop considerations

If the decision is to plant true cover crops without the intention of harvesting, winter or spring cereal grains are probably the best options. These include oats, wheat, barley, rye and triticale. However, whichever cover crop species is planted, it can be planted earlier to take advantage of the prevent planting situation.

Brassicas (turnips, kale, forage rape, radishes) are good crops that can be planted in July and August for grazing and forage. When planted with cereal grains, brassicas will provide good grazing after Nov. 1 but will not survive winter.

Legumes are an option, but should be planted later in the summer; therefore, they will not aid in erosion control or weed suppression in the first half of the growing season.

Our wet spring has not given farmers the best opportunity to maximize their businesses. Prevented planting presents some unique challenges, but there are viable options to continue to protect productive land while weathering a season without a traditional cash crop.

Cover crops and summer forage offer alternatives that can deliver positive results. You can find cover crop information at Iowa Learning Farms.

Licht is an ISU assistant professor, Extension cropping systems specialist and Conservation Learning Group leadership team member. Contact him at [email protected].

About the Author(s)

Mark Licht

Mark Licht is an assistant professor and Extension cropping systems specialist with Iowa State University Extension. His Extension, research and teaching program is focused on how to holistically manage Iowa cropping systems to achieve productivity, profitability and environmental goals. His areas of expertise include cropping systems, cover crops, and corn and soybean management.

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