Indiana

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.
Figure 1: A growing oats/radish mix (Eileen Kladivko)
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.

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Midwest Cover Crops Council (MCCC-100)
Purdue Extension (AY-356-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 corn-soybean rotation. Planting a cover crop ahead of a soybean cash crop is often the easiest way to introduce cover crops into your rotation.

Planning and Preparation

Planning—Educate yourself. Start small. Be timely. Prioritize management based on your purpose and objectives.
Corn hybrid and planting—If possible, plant the preceding corn crop early and use an early maturity corn hybrid. One strategy is to use cover crops on the field you usually harvest first, on sloping ground, or on a field where you can watch it regularly, and to plant your earliest maturity hybrid on that field.
Residual corn herbicides—Cereal rye can be seeded and a successful stand will occur in the fall following most of the spring-applied residuals used in corn. However, if cereal rye will be grazed or fed to livestock, there are some restrictions (see Resources section).
Seed purchase—Order cereal rye seed early. Named varieties can produce substantially more growth or more predictable growth and maturity, but they are more expensive than VNS (variety not stated) seed. Start with VNS seed with a good germination rate purchased from a reputable seed dealer. Note that this means the seed has been cleaned, tested for germination, and has a seed tag even though it is VNS.

Fall Work

Corn harvest—Harvest fields where cereal rye is to be planted as early as possible.
Tillage or no-tillage—To allow for adequate cover crop growth, it is best or easier if no full-width tillage is planned for after rye planting or before intended rye termination date. Thus, it is easier to integrate cover crops into no-till or strip-till systems.
Timing of planting—Ideally, plant cereal rye as soon after harvest as possible and before two weeks after the 50% frost date. In northern Indiana, this would be before Nov. 10; in southern Indiana, before Nov. 25. Use the Selector Tool for more precise dates for your county.
Seeding rate—Drilled seeding rate: 45–60 lbs./acre. Broadcast with shallow incorporation: 50–65 lbs./acre. These rates are based on high-quality seed with germination rates of 85–98%.
Planting method—Drill to 0.75–1.50 inches deep or broadcast with shallow incorporation. An air-seeder mounted on a vertical tillage tool can also be used.
Fertility or liming—If applying P, K, or lime, complete the application prior to the seeding operation or apply to the growing rye before the ground freezes. If it is necessary to inject manure, low-disturbance injectors are available that will cause minimal damage to the cereal rye. Surface application of liquid manure on top of the rye 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 cereal rye with minimal damage by using modern spreading equipment that provides even distribution.

Figure 1: Terminate cereal rye growth when approximately 6 inches in height (shown here). (Eileen Kladivko)
Figure 1: Terminate cereal rye growth when approximately 6 inches in
height (shown here). (Eileen Kladivko)
Spring Work

Scouting—In the spring, scout your cereal rye cover crop to determine how well it is growing and its coverage. But if rainfall is below normal, scout also to monitor soil moisture in case earlier termination is needed.
Termination timing—Terminate the cereal rye in the spring when plants are 6 to 12 inches tall and actively growing or about two weeks before planting soybean— whichever comes first. Many growers will successfully plant soybean into terminated cereal rye much taller than 12 inches, especially if weed control is a primary purpose, but new cover crop users should terminate when the cereal rye is smaller (see Figure 1).
Termination herbicide—Cereal rye can easily be terminated with a full rate of glyphosate (minimum of 1 lb. acid equivalent [ae]/acre) after dormancy breaks in the spring. Effectiveness and rapidity of termination improves if rye is rapidly growing and air temperatures are warmer. Larger rye, rye past the boot stage, or rye sprayed during cooler weather can be more difficult to kill or will die more slowly. Be careful of metribuzen and metribuzen premixes antagonizing glyphosate if weather is cool and cloudy near the application date.
Termination modifications for dry weather—Watch the weather and be ready to modify your termination plans. In a dry spring, the cereal rye cover crop has 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, when it has been very difficult to get into the fields to spray, be ready to take advantage of any break in the weather and/or use low axle weight sprayers. If projected soybean planting is less than 10 days away and the rye is tall, then it often works better to spray within a day or two of planting. It is usually better to plant either into brown, dead rye plants or into standing green plants rather than into large, dying, yellow/green (“rubbery”) cereal rye plants that have fallen on the soil surface and formed a mat. See Purdue Extension publication AY-353-W (in Resources section) for more details.
Soybean planting—It is usually best to no-till plant soybean into the dead/dry or standing cereal rye cover crop. Almost all modern planters and drills are fully capable of planting soybean into a cereal rye cover crop. 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 soybean planting, scout for soybean emergence and population. Additionally, scout for weeds since substantial cereal rye 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
Managing Cover Crops: An Introduction to Integrating Cover Crops into a Corn-Soybean Rotation (Purdue Extension publication AY-353-W)
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)
Recommended Cover Crop Seeding Methods and Tools (Agronomy Technical Notes)—available from the USDA–Natural Resources Conservation Service

Authors

Eileen Kladivko, Purdue University; Shalamar Armstrong, Purdue University; and Anna Morrow, Midwest Cover Crops Council

Reviewers and Contributors

Marisol Berti, North Dakota State University; Barry Fisher, USDA-NRCS; William Johnson, Purdue University; Tom Kaspar, USDA–Agricultural Research Service (retired); DeAnn Presley, Kansas State University; Vaughn Sothman, Sharp Brothers Seed Co., Kansas; and Anne Verhallen, Ontario Ministry of Agriculture, Food and Rural Affairs

The Midwest Cover Crops Council (www.https://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.

Revised May 2019

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. ©2019 by MCCC. All rights reserved.

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