October 2020
Authors: Gared Shaffer, David Karki, Anthony Bly, Ruth Beck, Sara Bauder, Paul O. Johnson- SDSU Extension
Source: SDSU Extension
Midwest Cover Crops Council (MCCC-135)
This publication is intended to provide a starting point for farmers who are new to growing cover crops. With experience, farmers may fine-tune the use of cover crops for their systems.
Introduction
The following recipe provides an introductory approach to integrating a cover crop into a wheat-based rotation with soybean or corn. Planting a cover crop blend that predominantly consists of cool-season species and is winter-killed adds diversity and provides soil armor through summer and spring. However, in some situations added ground cover in the spring in combination with excess soil moisture could be a problem unless winter cereals (winter rye, wheat, or triticale) are included in the mix.
Planning and Preparation
- Planning—Consult with university Extension staff, local NRCS staff, and experienced producers to gain insight on the practice. Start small while exploring new practices. In South Dakota, timeliness is important due to the shorter growing window. Always focus on your objectives, such as whether you are growing the cover crop for ground cover, fall grazing, nutrient cycling, etc.
- Small-grain variety and planting—Small-grain varieties such as wheat or oats do not need to be changed or modified to incorporate cover crops following grain harvest or haying. Planting small grains early in the spring is important for good growth and development, which also typically results in earlier harvest and allows more time for cover crops to grow before a frost.
- Residual herbicides—A blend consisting primarily of cool-season cover crops such as cereal grains (oat, barley), brassicas (radish, turnip, rapeseed), and legumes (field pea), and some warm-season grasses such as millet and sorghum-sudangrass have shown good tolerance to commonly used herbicides. If the cover crop is intended for grazing in the fall/winter, it is critical to follow grazing restrictions stated on the herbicide label.
- Seed source—Planning ahead and ordering seed early with the objective in mind is important. Most cover crop seed dealers have their own pre-mixed blends but are willing to custom-mix upon request. Follow the seed label and review the individual species to make sure that the growth habit of each is ideal for the planting time. If opting for a mix of only one or two species, labeled varieties usually perform better than variety not stated (VNS) seeds.
Summer/Fall Work
- Harvest—Harvest wheat/oats at the normal time. If weed pressure is high, you can spray glyphosate or other herbicides with the least residual effects. Herbicides are a better option than tillage as stirring the soil can dry it out and reduce germination. Baling small-grain residue is common in South Dakota but can make establishment of the cover crop difficult where the windrows were present.
- Timing of planting—In South Dakota, wheat and/or oats are generally harvested from the second week of July to the first week of August. Planting cover crops immediately following harvest is recommended so that the seasonal window can be maximized. A mix consisting mostly of cool-season annual species grows well as temperatures start to gradually decrease. Use the Cover Crop Selector Tool (in Resources section) for precise seeding dates.
- Planting method—Determining seeding depth is tricky when planting a mix with various seed sizes. Drilling to a moderate depth of 0.50–0.75 inch will be good for most mixes. Tilling or soil disturbance is not recommended as this may cause unwanted weed growth.
- Cover crop types—Diversity of species in a mix is good and typically will provide the best benefits. The general rule of thumb is to select cover crops that are of contrasting growth habit to the subsequent cash crop. For example, if the next season’s cash crop is corn, planting cover crop blends that have a higher proportion of cool-season broadleaves is suggested; if the next season’s crop is soybean, then a mix with more cool-season grasses would be ideal. If wheat or other small grains are to be raised for seed purposes, cover crop blends that contain winter cereals (e.g., winter wheat, winter rye, winter triticale) are not suggested.
- Seeding rate—Seed size and proportion in the mix determines the seeding rates. For example, a mix high in large-seed species such as peas and oats can be higher than the ones dominant in brassicas. Typically, the seeding rate of commonly marketed cover crop mixes can range from 15 to 30 lbs./acre. The full seeding rate of individual species can be found in Cover Crop: Common Species and Properties of South Dakota (see Resources).
- Tillage—Tillage or soil disturbance is not suggested.
- Fertility—Fertilizer is not usually required for a cover crop mix with well-balanced species. However, producers who have livestock and intend to maximize growth for fall/winter grazing have shown interest in using low rates of fertilizer. Although there are no specific guidelines on fertilizer rates for various cover crop blends, using nitrogen rates in the range of 30–40 lbs. N/acre can enhance cover crop growth and establishment, especially following high-yielding wheat crops.
- Grazing—Producers who prefer to grow cover crops after small grains for grazing in the fall/winter can slightly increase the proportion of cool-season grass species such as oats and barley. Include at least 60% grasses in the mix for grazing. To assist in calculating the amount of grazing your cover crop can offer, refer to the Grazing Cover Crop Calculation App (in Resources).
Spring Work
- Starter fertilizer—No modifications to your typical fertilization program are required for planting soybean or corn. However, there are a few considerations for planting corn. After a cover crop has winter-killed, get a current soil test to look at nitrates and sulfur. Cover crops can sequester nitrogen, which is a desired attribute to reduce leaching or runoff. But mixes with a high proportion of Brassica species (radish, turnip, rapeseed) can use quite a bit of sulfur. Soil-testing and applying these nutrients as needed to minimize the chance of nutrient deficiency is a good practice.
- Termination—Typical cover crop blends should winter-kill in South Dakota. However, mild winters can leave a few plants the next spring. Timely scouting and herbicide application as needed is suggested for uniform control of cover crop plants that survived the winter. Some mixes with winter annuals such as winter triticale, cereal rye, or winter camelina will require spring termination.
- Soybean or corn planting—It is usually best to no-till plant cash crops into the dead/dry or standing cover crop. Almost all modern planters and drills are fully capable of planting soybean or corn into terminated cover crop residue. Check planting depth and seed furrow closure shortly after beginning.
- Scouting—After planting soybean or corn, scout for crop emergence and population. Additionally, scout for weeds since cover crop residue can often delay emergence of annual weeds, which may delay the application of post-emergence herbicides.
Resources
Cover Crop Selector Tool—available from the Midwest Cover Crops Council, www.midwestcovercrops.org
Cover Crop Species Selection for Grazing (USDA-NRCS publication SD-FS-56)
Herbicide Residual Effects on Cover Crops after Wheat (South Dakota State University Extension)
Cover Crop: Common Species and Properties of South Dakota (USDA-NRCS)
Grazing Cover Crop Calculation App (Jotform app)
Author
David Karki, South Dakota State University Extension (Note: This publication was adapted with consent from MCCC under a joint project to produce customized introductory guidance about cover crops for all member states/provinces.)
Reviewers and Contributors
Eric Barsness, USDA-NRCS; Anthony Bly, South Dakota State University Extension; Eileen Kladivko, Purdue University; Anna Morrow, Midwest Cover Crops Council
The Midwest Cover Crops Council (www.midwestcovercrops.org) aims to facilitate widespread adoption of cover crops throughout the Midwest by providing educational/outreach resources and programs, conducting new research, and communicating about cover crops to the public.
Funding for this project was provided by McKnight Foundation.
December 2022
The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual’s income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA’s TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer. ©2022 by MCCC. All rights reserved.
Midwest Cover Crops Council (MCCC-127)
University of Guelph (SAG-FS-21-001)
This publication is intended to provide a starting point for farmers who are new to growing cover crops. With experience, farmers may fine-tune the use of cover crops for their systems.
Introduction
The following recipe provides an introductory approach to underseeding a red clover cover crop into winter wheat prior to corn. Adding red clover to a wheat-corn-soybean rotation can improve corn and soybean yields, promote better soil, and provide a nitrogen credit, depending on growth and tillage. With good management, these potential benefits make a red clover cover crop worth investing in.
Planning and Preparation
- Planning—Start small with one field. Prioritize cover crop management based on your goals. Avoid fields with a history of poor drainage, water ponding, or fertility issues.
- Wheat variety and planting—No modifications to wheat variety and planting are required for the successful adoption of a red clover cover crop.
- Winter wheat herbicides—Bromoxynil or MCPA are registered for wheat underseeded with red clover but with specific precautions to avoid injury. See Table 7-3, Herbicide Treatment Rates for Cereals, in Guide to Weed Control: Field Crops (see Resources).
- Tillage or no-tillage—Red clover establishment may be more challenging in no-till systems. In fields with high residue, light tillage prior to wheat planting may improve seed-soil contact and establishment of red clover.
- Fertility or liming—No changes are needed if applying P, K, lime, or manure in the fall before wheat planting.
- Seed purchase—Seed prices can vary depending on the time of year; therefore, it is best to order seeds early. Red clover seed is readily available across Ontario. (See Cover Crop Seed Suppliers in Resources.)
- Variety selection—Ontario growers can choose between double-cut or single-cut varieties, or a mix of both. Single-cut types tend to have less top growth than double-cut types. In thin wheat stands, choose single-cut; otherwise the height of double-cut may pose an issue when combining. Single-cut varieties are slightly more drought tolerant and may be favored in strip-till or no-till systems.
Late-Winter Work
- Planting method and timing—Red clover can be broadcast into winter wheat just before green-up while the ground is still frozen and fields are fit to drive on. The freeze-thaw action will work the seeds into the ground. (See Underseeding Red Clover into Winter Wheat in Resources.)
- Seeding rate for red clover—Broadcast red clover at a rate of 7–9 lbs/acre. For more information, see Agronomy Guide for Field Crops (in Resources).
Summer Work
- Scouting—Look for red clover plants to have about 5 leaves during late May before the dry summer period.
- Wheat harvest—Harvest wheat at the normal time. The red clover will continue growing until terminated.
Post-Wheat Harvest Work
- Evaluating a clover stand—The goal is a uniform stand of at least 3 to 4 plants per square foot. Clover stands may seem to disappear under hot and dry conditions immediately before wheat harvest but will often recover within one to two weeks.
- Filling in patches—If red clover stands are inconsistent (Figure 1), red clover or crimson clover can either be drilled or broadcast into gaps. Alternatively, forage pea, an oat-pea mix or an oat-radish mix (see After Wheat, Going to Corn or Soybean in Resources) can be planted to suppress weeds.
- Mowing—Scout and clip or mow the field before common ragweed or other weeds go to seed (Figure 1).
- Termination—Significant root mass accumulates in the month of October, so it is best to delay termination as late as possible. There are two main methods:
- Herbicide—Terminate red clover in the fall when it is actively growing and herbicides are most effective. Spring termination is less successful. (See page 5 of the Guide to Weed Control: Field Crops.)
- Tillage—Red clover can be terminated using a moldboard plow in the fall or spring. Some growers do not plow and will follow up their herbicide termination with some tillage, but disc ripping will not effectively terminate red clover on its own.
Spring Work
- Fertilizer—The nitrogen application rate to corn can be reduced by 73 lbs/acre for plowed clover and by 60 lbs/acre in a no-till system. (See page 24 of the Agronomy Guide for Field Crops.)
- Corn planting—Check planting depth and seed furrow closure shortly after beginning to plant into the cover crop residue as usually some adjustments are needed.
- Scouting—After corn planting, scout for crop emergence and population. Slug damage may occur if the clover was not tilled. Additionally, scout for red clover escapes and weeds since cover crop residue can often delay the emergence of annual weeds, which may delay the application of any post-emergence herbicides.
Resources
Cover Crop Selector Tool — available from Midwest Cover Crops Council
Guide to Weed Control: Field Crops (OMAFRA publication 75A)
Underseeding Red Clover into Winter Wheat (Field Crop News, OMAFRA)
Agronomy Guide for Field Crops (OMAFRA publication 811)
After Wheat, Going to Corn or Soybean: Use an Oat-Radish Mix (Ontario Cover Crop Recipe Series, MCCC-128/SAG-FS-21-002)—available from Midwest Cover Crops Council, Cover Crop Recipes
Fall Control of a Red Clover Cover Crop (Field Crop News, OMAFRA)
Authors
Jordan Grigg, Cameron Ogilvie, and Laura Van Eerd, University of Guelph; Anne Verhallen, OMAFRA (Note: This publication was adapted with consent from MCCC under a joint project to produce customized introductory guidance about cover crops for all member states/provinces.)
Reviewers and Contributors
Joanna Follings, OMAFRA; David Hooker, University of Guelph; Tatianna Lozier, Upper Thames River Conservation Authority; Anne Vanasse, Université Laval; Marty Vermey, Grain Farmers of Ontario
The Midwest Cover Crops Council (www.https://www.midwestcovercrops.org) aims to facilitate widespread adoption of cover crops throughout the U.S. Midwest and Ontario by providing educational/outreach resources and programs, conducting new research, and communicating about cover crops to the public.
Funding for this project was provided by McKnight Foundation.
July 2021
The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual’s income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA’s TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer. ©2021 by MCCC. All rights reserved.
Kim Cassida and Jerry Lindquist – Michigan State University Extension
March 2018
Frost-Seeding: an Effective Forage Establishment Practice for Michigan
Eric Lee-Mader, Anne Stine, Jarrod Fowler, Jennifer Hopwood and Mace Vaughanby – Xerces Society for Invertebrate Conservation with contributions from the USDA Natural Resources Conservation Service
August 2017