Tis the season! No, we’re not talking about the holiday season— we’re talking about cover crop season! It’s finally here, and soon cover crops will be flown on aerially, drilled into the soil, or applied via other planting methods across the country. Whether you are a new cover crop user or a seasoned veteran, it’s never too early to start thinking about what you intend to plant. Adding cover crops to your operation can be a step in the right direction to improve the health of your soil. In this article, we will highlight 5 different species for you to consider utilizing this fall to meet your goals.

5 Species of Cover Crops to Try This Fall:

Photo credit: Cereal Rye Variety Trial 2019 - Practical Farmers of Iowa

Cereal Rye

• Cool season grass
• Excellent scavenger of excess nutrients
• Provides soil erosion protection
• Suppresses weeds
• Winter hardy

Cereal rye is probably the most common cover crop planted, especially in the Corn Belt. Cereal rye is a “jack of all trades” in terms of the multiple benefits it has to offer. Most growers prefer planting cereal rye after corn harvest, prior to planting soybeans the following spring. This preference is due to nitrogen which the decomposing cereal rye can tie up, leaving that nutrient unavailable ahead of planting corn. Cereal rye puts on most of its growth in the spring, which can allow it to become tall and stemmy if not managed correctly. The more mature the cereal rye is allowed to get, the more nitrogen it can tie up. The slow process of breaking down the cereal rye to the point that it releases its stored nitrogen take a lot of time, which can leave the nitrogen unavailable to the corn crop when the corn needs it most. (1) However, this initial tie-up in nitrogen results in it being stored as organic matter which crops can use later on.

Photo credit: Oilseed radish (Raphanus sativus) Plant Guide (usda.gov)

Oilseed Radish

• Cool season broadleaf - Brassica
• Helps break up subsoil compaction
• Long taproot makes it an excellent scavenger of excess nutrients
• Suppresses weeds
• Typically winter killed after a few nights in the high teens (5)

Adding oilseed radishes to a cover crop mix or simply seeding them by themselves can be very beneficial. To maximize your farm’s nutrient scavenging potential, add oilseed radishes and cereal rye to your cover crop mix. (2)

Photo credit: Other brassicas – Crops and Soils (wisc.edu)

Turnip

• Cool season broadleaf - Brassica
• Best of the five at breaking up both subsoil AND surface compaction
• Suppresses weeds
• Winter hardy until temperatures consistently get below 25°F, then winterkilled (7)

Turnips are not only great at breaking up subsoil compaction but are excellent for alleviating surface compaction as well. This is due to the large bulb that a turnip grows just below the ground surface. Like radishes, turnips also grow quite rapidly and assist in shading the soil, which in return suppresses weeds. (3)

Photo credit: Other brassicas – Crops and Soils (wisc.edu)

Crimson Clover

• Cool season legume
• Efficient nitrogen fixer
• Reduces erosion
• Suppresses weeds
• High shade tolerance, grows well in cooler temps (4)
• Needs inoculated prior to planting

Crimson clover is typically hardy through USDA plant hardiness zone 6. While it is often considered a winter-kill species in USDA plant hardiness zone 5, it can survive if the plant is protected from the snow, especially during extremely cold temperatures. Adding crimson clover to a cover crop mix with a cool season grass will provide tap roots and fibrous surface roots that aid in both nutrient scavenging in reducing nitrogen leaching. (8)

Photo credit: Winter Field Pea as a Fall-planted Broadleaf Crop for the Panhandle? | CropWatch | University of Nebraska–Lincoln (unl.edu)

Austrian Winter Pea

• Cool season legume
• Efficient nitrogen fixer
• Reduces Erosion
• Alleviates surface compaction
• Winter hardy – may winter kill when temperatures reach the low teens and the plant is exposed (9)

Winter peas, like cereal rye, are also a very versatile cover crop that can be utilized if you want to capture a variety of benefits with one species. Austrian winter peas have been shown to thrive in many different soil types, including soils that are unproductive. When thrown into the mix with a winter cereal grain, the Austrian winter pea can help reduce the carbon-nitrogen ratio (C:N). This cover crop can also be an important helper in breaking down the residue of any winter cereals in the mix, allowing the succeeding cash crops to capture those nutrients released from the grain residue. (6)

In summary, you can see how many overlapping benefits these 5 species have! And we’ve barely scratched the surface on all the possible cover crops growers have available to them. There are many other cover crop species to choose from that offer a wide range of soil-improving benefits. When choosing a cover crop species or a cover crop mix, please ensure you follow your region’s seeding dates and recommended seeding rates for each species to have the best success possible. And most importantly, have a goal in mind when considering cover crops for your operation. Is your goal improved soil health? Is it weed suppression? Nutrient scavenging? Do you have a need for grazing cover crops? These are important questions to ask yourself when choosing what cover crop species are right for you.

References:

(1) Managing Cover Crops Profitably, 3rd Edition. (2007) Cereal Rye. Page 100. SARE Outreach. Retrieved from: Cereal Rye - SARE (sare.org) (2) Michigan State University, MSU Extension Cover Crops. Oilseed Radish. Retrieved from: Oilseed Radish - Cover Crops (msu.edu) (3) Baas, D., and Schultheis, E. (2020, March 1) Benefits of Brassicas as Cover Crops. Michigan State University, MSU Extension Cover Crops. Retrieved from: Benefits of Brassicas as cover crops - Cover Crops (msu.edu) (4) Michigan State University, MSU Extension Cover Crops. Crimson Clover. Retrieved from: Crimson Clover - Cover Crops (msu.edu) (5) University of Maryland Extension. (2020, July) No-till Spring Vegetables After Forage Radish Cover Crop. FS-1134, Page 1. Retrieved from: No-till spring vegetables after forage radish cover crop.pdf (umd.edu)
(6) Roberts, T., Ross, J., Norsworthy, J., Faske, T., Thrash, B., Bateman, N. (2020, April 16) Austrian Winter Pea as a Winter Cover Crop. FSA1095, pages 1-6. University of Arkansas, Division of Agriculture, Research & Extension. Retrieved from: Austrian Winter Pea as Winter Cover Crop (uada.edu) (7) University of Massachusetts Amherst, Center for Agriculture, Food, and the Environment, UMASS Extension Vegetable Program. (2013, January) Cover Crops, Brassicas. Retrieved from: Vegetable: Cover Crops, Brassicas | Center for Agriculture, Food, and the Environment at UMass Amherst (ag.umass.edu) (8) Managing Cover Crops Profitably, 3rd Edition. (2007) Crimson Clover (Trifolium incarnatum). Page 130. SARE Outreach. Retrieved from: Crimson Clover - SARE (sare.org) (9) Pavek, P.L.S. 2012. Plant fact sheet for pea (Pisum sativum L.). USDA-Natural Resources Conservation Service, Pullman, WA. Retrieved from: Pea Plant Fact Sheet (usda.gov)