Skip to main content

Cover Crop Considerations for Planting Season 2019

BROOKINGS, S.D. – Cover crops may be good options for South Dakota growers unable to plant due to high waters and saturated soils.

“In many areas, typical cash crops will not be a possibility,” said Anthony Bly, SDSU Extension Soils Field Specialist.

However, he added, leaving fields or large areas in fields fallow is not a good option.

“Not planting can have detrimental impacts on the 2020 crop. After a fallow season, corn, sorghum, wheat and other crops could experience phosphorus deficiency due to lack of phosphorus uptake.”

— Anthony Bly, SDSU Extension Soils Field Specialist

A phosphorus deficiency can stunt growth and create uneven stands. “This is referred to as “fallow syndrome” and is the result of reduced populations of mycorrhizal fungi found in soils, which help to facilitate phosphorus uptake by roots,” explained Bly.

Lower populations of these fungi result from tillage and a lack of growing plants during the fallow period. In addition to this issue, Bly said fallow practices leave soil bare and unprotected with no living root activity. This can lead to erosion, soil crusting, reduced carbon and a decline in overall soil health.

Ruth Beck, SDSU Extension Agronomy Field Specialist encourages farmers to consider planting annual cover crops as an alternative to fallow this growing season.

“There are numerous cover and forage crops that can be used to help address wet fields,” Beck said.

Cover crops can contribute to the overall health of soils reducing erosion, increasing plant diversity, capturing/recycling nutrients, increasing soil biological populations, increasing soil organic matter(carbon), suppressing weed growth, improving moisture management and providing more forage if needed.

“Cover crops can also improve yield and economic potential for the following crops,” Beck explained.

“Cover crops can also improve yield and economic potential for the following crops.”

— Ruth Beck, SDSU Extension Agronomy Field Specialist

Cover crop mixes spread risk and provide a diversity of species tailored to particular objectives. Multiple planting methods also make cover crops a flexible option. Methods include: drilling, air seeding, aerial seeding and broadcast seeding.

Prior to planting any cover crop, producers should check the herbicide history of fields. “It can be assumed that any herbicide with a rotation interval that impacts a common cash crop will most likely affect a cover crop species from within a similar crop type or plant family,” said Sara Bauder, SDSU Extension Agronomy Field Specialist.

For example, any herbicide applied, that has a long rotation interval requirement before peas, will most likely also have a long rotation interval for lentils and other legumes.

“This is a general rule of thumb,” Bauder said. “Most herbicide labels do not list rotation restrictions for many cover crop species.”

Warm or cool season?

There are several tools and resources to help choose the right cover crop mix for a field. The time within the growing season in which seeding occurs will help to determine whether to plant cool season or warm season species, or a mixture of both.

“If soils allow for planting by early to mid-summer, warm season cover crops should be the primary plant type in the mix,” Beck said. “However, if a producer chooses to wait until later summer to plant (after August 10), cool season crops should be the primary crop of choice as they thrive better in cooler fall temperatures.”

Planting a mix of broadleaves and grasses reduces risk, and the crop canopy will likely close faster, providing weed control, pest management, soil biological diversity and more. 

“Each cover crop provides unique benefits to the soil,” Beck said.
She said growers need to take careful consideration when choosing a mix.
For basic information on species, see Table 1.

For assistance getting started creating a mix for your growing conditions and objectives, contact SDSU Extension staff or your local South Dakota Natural Resources Conservation Service (NRCS) staff.

Watch insurance dates and restrictions

Before planting a cover or forage crop, producers who are signed up for Conservation Stewardship Program, Environment Quality Incentive Program or other government programs, SDSU Extension staff encourage them to check with their local NRCS office to ensure they are following contract requirements.

In addition, crop insurance, planting dates and proven yields have to be considered as part of a whole farm risk management strategy.

For those who choose prevented planting insurance, pay careful attention to dates and stipulations. While the planting deadlines for insurance of small grains and corn has passed, soybean (June 10) deadlines are still approaching.

“If producers do not make prevented planting deadlines and choose not to plant intended cash crops, cover crops may be an excellent alternative,” Bauder said.

In order to receive the prevent plant payment be sure to do the following:

  • For 100 percent payout, cover crops must be planted after the final plant deadline for your intended crop, but may be planted during the late plant period. This is a change from previous years when cover crops could not be planted until after the ‘late plant period’. 
  • Check with your crop insurance agent to ensure you are meeting crop insurance specifications for seeding rate, species, and deadlines.
  • Grazing or haying must not take place until November 1, 2019 for full payment. Keep this in mind when making decisions on cover crop mixtures and planting dates.
A graphic describing classification, growth cycle, plant architecture, and relative water use of common US cover crops. For more information, visit:
Table 1. USDA-ARS Cover Crop Chart. Courtesy: USDA-ARS

Courtesy of USDA-ARS. Table 1: A graphic describing classification, growth cycle, plant architecture, and relative water use of common U.S. cover crops.