October 2020
Authors: Gared Shaffer, David Karki, Anthony Bly, Ruth Beck, Sara Bauder, Paul O. Johnson- SDSU Extension
Source: SDSU Extension
Drew Kientzy, Ryan Milhollin, Charles Ellis, and Ray Massey – University of Missouri
August 18, 2023
Source link here.
Midwest Cover Crops Council (MCCC-136)
University of Nebraska Extension (G2351)
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
This publication provides an introductory approach to integrating cover crops following corn silage and before corn or soybeans. These cover crops can have many benefits, such as erosion control, weed suppression, improved soil health, and quality forage production.
Planning and Preparation
- Planning—Start planning early. Educate yourself by talking to experienced cover crop users, attending conferences and field days, and reading as much as possible about cover crops. Start small and determine your purpose and objectives for using cover crops. If needed, arrange for equipment, additional labor, or custom operators.
- Corn hybrid and planting—Plant the corn silage crop early and use a hybrid within the adapted maturity range for your location. This will allow you to plant your cover crop earlier and increase fall growth.
- Residual corn herbicides—Consult your agricultural supplier regarding residual corn herbicides that could cause concerns for newly planted cover crops. Cereal grains (rye, oats, and wheat) are not affected by most pre-emergence residual herbicides but are somewhat affected by post-emergence herbicides. If using rapeseed in your mix, it may be sensitive to carryover from herbicides. If cover crops will be grazed, additional herbicide restrictions may apply.
- Seed purchase—Order your seed early from a reputable seed supplier to ensure a good germination rate, purity of seed, and that all seed has a seed analysis tag. Specific varieties of cereal rye, wheat, or oats may produce significantly more growth, but they are also more expensive than variety not stated (VNS) seed.
Fall Work
- Corn silage harvest—Harvest fields where a cover crop is to be planted first, if possible.
- Tillage or no-tillage—No-till drilling into corn silage stubble is usually the best strategy to use unless tillage is necessary to incorporate manure, fertilizer, or lime, or needed to smooth out the seedbed, such as deep wheel tracks after corn silage harvest. The tillage should be completed as soon as possible and before seeding the cover crop.
- Timing of planting—Ideally, plant your cover crop as soon as possible after silage harvest. Plant the oats cover crop mix or oats alone by Sept. 7. Oats will not grow enough to justify their use after this date. For winter wheat only, plant before 50% frost date. For rye only, plant before two weeks after the 50% frost date. In northern Nebraska, this would be before Oct.15; in southern Nebraska, before Nov. 1. Use the Cover Crop Selector Tool (in the Resources section) for more precise dates for your county. These dates are guidelines; the sooner these cover crops are planted in the fall, the better.
- Seeding rate for a mix—Drilled: oats, 20 lbs./acre; wheat, triticale, or rye, 25 lbs./acre; rapeseed, 1 lb./acre. Broadcast: oats, 25 lbs./acre; wheat, triticale, or rye, 30 lbs./acre; rapeseed, 2 lbs./acre.
- Seeding rate for oats alone—Drilled: 30–40 lbs./acre; if grazed, 40–55 lbs./acre.
- Seeding rate for wheat or rye alone—25–35 lbs./acre; if grazed, 45–60 lbs./acre. Shallow incorporation: oats, 45–60 lbs./acre; wheat, 50–65 lbs./acre; rye, 50–65 lbs./acre.
- Planting method—If you include the brassica rapeseed, seeding depth is limited as these are small seeds. A depth of 0.50 inch is best. If you have a drill with two boxes, you can dribble the rapeseed on top of the ground and then drill your cereal grain to a depth of 0.75–1.50 inches.
Spring Work
- Termination timing—Oats and rapeseed will usually winter-kill. Terminate the wheat, triticale, or cereal rye in the spring when plants are 6–12 inches tall and actively growing or about two weeks before planting corn or soybeans—whichever comes first. Many experienced growers will terminate wheat, triticale, or cereal rye the same day as planting corn or soybean, or within one week, particularly in irrigated situations. This provides an extra benefit for weed control. Risk of wheat stem maggot damage to corn seedlings increases when corn is planted into a green, non-terminated, winter cereal grain cover crop. Another concern is that cover crop residue with a high carbon-to-N (C:N) ratio can reduce soil-available N. Starter N fertilizer is recommended at planting or sidedress as soon as possible to offset this early immobilization when the corn has a high N demand. New cover crop users should terminate earlier when the cereal crops are smaller for corn. Planting green into soybeans is much less risky and could be implemented by new cover crop users.
- Termination herbicide—Wheat, triticale, and cereal rye can typically be terminated with a full rate of glyphosate (1 lb. acid equivalent/acre) after these crops begin growing in the spring. Effectiveness and rapidity of termination improve if winter cereal grain grows rapidly and air temperatures are warmer.
- Termination modifications for dry weather—Watch the weather and be ready to modify your termination plans. In a dry spring, cereal grain crops have the potential to use moisture that the cash crop will need, so terminate cover crops sooner to allow rainfall to make up the deficit.
- Termination modifications for wet weather—In a wet spring, be ready to take advantage of any break in the weather and/or use low axle weight sprayers.
- Option to harvest cereal rye, wheat, or triticale as a silage crop—A cereal grain cover crop planted in the fall and harvested at boot stage can provide a substantial amount of good quality forage. Waiting for the cereal grain cover crop to reach the boot stage (mid-May to early June) will delay planting of the next corn or soybean crop. If this crop is to be insured, then the small-grain cover crop should be terminated and corn or soybeans planted before the crop insurance late-planting deadline.
- Corn or soybean planting—Almost all modern planters and drills are fully capable of planting corn or soybeans into a clean, small-grain cover crop. Planter adjustments are usually needed to ensure correct planting depth and seed furrow closure.
- Scouting after planting—Scout for corn or soybean emergence, population, and insect pests (e.g., wheat stem maggot in corn). Scout for weeds because substantial small-grain residue, especially cereal rye, can delay emergence of annual weeds, which may then delay the need for and timing of applying post-emergence herbicides.
Resources
Cover Crop Selector Tool —available from the Midwest Cover Crops Council, https://www.midwestcovercrops.org
Post Corn, Going to Soybean: Use Cereal Rye (Nebraska Cover Crop Recipe series, MCCC-107)
Post Corn Silage, Going to Corn: Use Cereal Rye (Iowa Cover Crop Recipe series, MCCC-121)
Post Corn Silage, Going to Soybean: Use Cereal Rye (Iowa Cover Crop Recipe series, MCCC-122)
Managing Residual Herbicides with Cover Crops (Institute of Agriculture and Natural Resources, Univ. of Nebraska)
How Herbicide Labels Restrict Using Cover Crops as Forage (Institute of Agriculture and Natural Resources, Univ. of Nebraska)
Corn and Soybean Herbicide Options for Planting Cover Crops for Forage in Fall (Institute of Agriculture and Natural Resources, Univ. of Nebraska)
Residual Herbicides and Fall Cover Crop Establishment (Purdue Extension Weed Science publication)
Terminating Cover Crops: Successful Cover Crop Termination with Herbicides (Purdue Extension publication WS-50-W)
Authors
Gary Lesoing and Katja Koehler-Cole, University of Nebraska-Lincoln (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
Caro Córdova, Nathan Mueller, and Jennifer Rees, University of Nebraska-Lincoln; 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-137)
University of Nebraska Extension (G2352)
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
This publication provides an introductory approach to integrating cover crops following wheat and before corn or soybeans. These cover crops can have many benefits, such as erosion control, improved soil health, weed suppression, and quality forage production.
Planning and Preparation
- Planning—Start planning early. Educate yourself by talking to experienced cover crop users, attending conferences and field days, and reading as much as possible about cover crops. Start small and determine your purpose and objectives for using cover crops. If needed, arrange for equipment, additional labor, or custom operators.
- Residual herbicides—Consult your agricultural supplier regarding residual wheat herbicides that could cause concerns for newly planted cover crops. If cover crops will be grazed, additional herbicide restrictions may apply.
- Seed purchase—Order your seed early from a reputable seed supplier to ensure a good germination rate, purity of seed, and that all seed has a seed analysis tag.
Summer Work
- Dryland vs. irrigation—Irrigation allows for flexibility in managing planting dates and provides some insurance against dry planting conditions. Dryland seedings should occur immediately following wheat harvest in July for warm- and cool-season mixes. If delayed until August, consider changing to a cool-season mix. Contact your local Extension personnel for more information.
- Residue management—Uniform spreading of chaff and straw is essential during wheat harvest in order to avoid interfering with the cover crop seeding operation.
- Nitrogen management—If growing a forage crop, a nitrogen application before seeding a cover crop may be beneficial to counteract tie-up caused by stubble. Consider taking soil samples after the wheat harvest to determine nitrate-nitrogen levels. Depending on the prior nitrogen management, wheat yield, and weather, some residual nitrogen should be accounted for. The addition of nitrogen (up to 50 lbs. N/acre) may be beneficial in increasing biomass production of many of the cover crops, e.g., forage sorghum, sorghum-sudangrass.
- Wheat curl mite—Volunteer winter wheat and some species in diverse cover crop mixes planted after wheat (e.g., sorghums, millets, oats, barley) can serve as a host for wheat curl mites. These mites are vectors for the wheat streak mosaic virus complex. Planting new winter wheat fields within two miles of this existing field may lead to yield losses in winter wheat fields. Applying a burndown herbicide before planting the cover crop may be an option to control volunteer wheat and reduce competition from weeds. Please read the herbicide label and consult with an agricultural supplier or local Extension personnel for more information.
- Planting cover crop—No-till drill into stubble at least 45–60 days before the 50% frost date for your area. For most of Nebraska, this mix will need to be planted before early September. Use the Cover Crop Selector Tool (in Resources section) for more precise dates for your county. For the highest cover crop productivity, seed immediately after wheat harvest. Seeding depth is limited by the brassica species in the mix (rapeseed) as these are small seeds. A depth of 0.50 inch is best.
- Seeding rate—Oats are used in most diversified mixes because they are an excellent carrier for the other seeds. Seeding rates per acre are: 16–24 lbs. of oats, 4 lbs. of forage sorghum or sorghum-sudangrass, 2 lbs. of pearl millet, 1 lb. of grain sorghum, 1 lb. of rapeseed, and 4 lbs. of buckwheat.
Spring Work
- Winterkill—All species in the mixture will usually winter-kill with the onset of hard freezes, which will eliminate the need for any changes to spring management.
- Cover crop termination—If you have something in the mix that overwinters or germinates and emerges in the spring, the general recommendation is to terminate the mixture approximately two weeks prior to planting the next cash crop. Termination can be achieved using a full rate of glyphosate.
Resources
Cover Crop Selector Tool —available from the Midwest Cover Crops Council, https://www.midwestcovercrops.org
Post Corn, Going to Soybean: Use Cereal Rye (Nebraska Cover Crop Recipe series, MCCC-107)
Post Corn Silage, Going to Corn: Use Cereal Rye (Iowa Cover Crop Recipe series, MCCC-121)
Post Corn Silage, Going to Soybean: Use Cereal Rye (Iowa Cover Crop Recipe series, MCCC-122)
Managing Residual Herbicides with Cover Crops (Institute of Agriculture and Natural Resources, Univ. of Nebraska)
How Herbicide Labels Restrict Using Cover Crops as Forage (Institute of Agriculture and Natural Resources, Univ. of Nebraska)
Corn and Soybean Herbicide Options for Planting Cover Crops for Forage in Fall (Institute of Agriculture and Natural Resources, Univ. of Nebraska)
Residual Herbicides and Fall Cover Crop Establishment (Purdue Extension Weed Science publication)
Terminating Cover Crops: Successful Cover Crop Termination with Herbicides (Purdue Extension publication WS-50-W)
Wheat Stem Maggot Adult Monitoring: A Pest of Cover Crop-to-Corn Transitions (Institute of Agriculture and Natural Resources, Univ. of Nebraska)
Research Update on Cover Crops after Winter Wheat Harvest (Institute of Agriculture and Natural Resources, Univ. of Nebraska)
Authors
Gary Lesoing and Katja Koehler-Cole, University of Nebraska-Lincoln (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
Caro Córdova, Nathan Mueller, and Jennifer Rees, University of Nebraska-Lincoln; Eileen Kladivko, Purdue University; Anna Morrow, Midwest Cover Crop 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-138)
Purdue Extension (AY-368-W)
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 rotation with soybean or corn. Planting oat and daikon-type radish cover crops after wheat (see Figure 1) and ahead of a soybean or corn cash crop is an easy way to introduce cover crops into your rotation because these cover crops both winter-kill and add important diversity to agricultural fields.
Planning and Preparation
- Planning—Educate yourself. Start small. Be timely. Prioritize management based on your purpose and objectives.
- Wheat variety and planting—No modifications to wheat variety and planting are required for the successful use of cover crops after wheat harvest.
- Residual wheat herbicides—Oats and radish are tolerant of most herbicides applied to the wheat crop in-season before flag leaf emergence. However, if the cover crop will be grazed or fed to livestock, there may be restrictions on herbicide use. See herbicide label for specific instructions.
- Seed purchase—Order cover crop seed early from a reputable seed dealer. Purchasing named varieties is preferred to buying variety not stated (VNS) seed. Important traits such as vegetative growth rate, cold and heat tolerance, disease resistance, or insect resistance of named varieties are known, whereas little is known about those traits with VNS seed. A general goal for a mix planted at this time is for it to remain vegetative and growing biomass late into fall or until it is terminated by freezing temperatures. For cover crop radishes (daikon-type), be sure to purchase a single variety since mixed varieties may have unpredictable emergence or bolt to flower immediately and produce seed rather than producing the desired large amounts of biomass and roots. Purchasing VNS oat seed will be less of a risk when obtaining it from a reputable dealer if it has been cleaned, tested for germination, and has a seed tag.
Summer/Fall Work
- Wheat harvest—Harvest wheat at the normal time in fields where a mix of oats and radish will be planted. If residue levels are high, consider removing straw. If straw is not harvested, cut the wheat high or use a stripper header and make sure that the combine distributes straw and chaff evenly across the swath.
- Planting time—Plant oats and radish anytime in August after wheat harvest and after any other field activities such as manure application or tile installation. Planting a cool-season annual, such as radish, prior to August is not recommended as it may result in flowering and seed production instead of quick coverage and biomass accumulation, which is the desired goal for this cover crop. Use the Cover Crop Selector Tool for precise seeding dates for your county.
- Planting method—Drill or plant radish and oats in narrow rows to a depth of 0.50–1.00 inch, depending on moisture, or broadcast with light incorporation. Note that disturbance of the soil, if any, should be light since excessive disturbance of wheat stubble may reduce cover crop benefits. Light tillage will likely synchronize volunteer wheat and cover crop emergence. Emerged winter wheat will overwinter and need to be terminated before corn or soybean seeding occurs the following spring.
- Seeding rate in oats/radish mix—Mix seeds prior to planting at the following rates (pure live seed, drilled or broadcast): oats, 18–36 lbs./acre; radish, 1–2 lbs./acre. Adjustments to your mix ratio can be made to customize to your specific situation. A higher rate of oats and lower rate of radish is recommended for highly erodible soils and areas sensitive to phosphorus loss. When radishes winter-kill, they will make the soil more erodible and release phosphorus. If you are planning to plant corn in the spring, a higher rate of radish as compared to oats is advised to lower the carbon-to-nitrogen (C:N) ratio of the residue.
- Tillage or no-tillage—Under most circumstances, it is easy for no-till planters to achieve excellent seed placement in the winter-terminated residues. If tillage is used, it is usually better to wait until spring in order to maintain surface cover to prevent erosion.
- Fertility or liming—If applying P, K, lime, or manure, complete the application, injection, and/or incorporation prior to seeding or apply to the growing oats and radish before the ground freezes. It is not advised to apply manure at seeding as high salt levels can result in poor germination. If injecting manure, low-disturbance injectors are available that will minimize damage to oats and radish. Surface application of liquid manure on top of the cover crop is not recommended. Surface broadcast of dry manure or litter should be done prior to seeding, but 4 tons or less can be applied to growing oats and radish with minimal damage provided it is evenly distributed.
Spring Work
- Starter fertilizer—No modifications to your typical fertilization program are required for planting soybean or corn after oats and radish use.
- Termination—Oats and radish should both terminate by winterkill. However, mild winters and good snow cover sometimes allow radish to overwinter. If this occurs, radishes are easily terminated with typical pre-plant herbicide applications.
- 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 an oat and radish cover crop. In some cases, the radish tuber will swell enough to cause soil heaving and/or leave holes following the desiccation of the tuber. By cash-crop planting time, this is seldom a no-till planting issue, particularly if the planter is equipped with row cleaners. Check planter attachments and settings such as row cleaners, closing wheels, and down pressure shortly after beginning to plant into the cover crop residue as some adjustments are usually needed for uniform seed depth, seed furrow closure, and ultimately, seedling emergence.
- Scouting—After soybean or corn planting, 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
Residual Herbicides and Fall Cover Crop Establishment (Purdue Extension Weed Science publication)
Authors
Anna Morrow, Midwest Cover Crops Council; Shalamar Armstrong, Keith Johnson, Eileen Kladivko, and Dan Quinn, Purdue University (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.)
Reviewer and Contributor
Barry Fisher, retired USDA–Natural Resources Conservation Service, Fisher Soil Health
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-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.