Cover crops after wheat harvest – five reliable options
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EmailPost-wheat harvest leaves an excellent opportunity to incorporate fall cover crops into your production system. Here’s five reliable options for cover cropping after wheat to get you started.
Wheat harvest in Michigan is complete, which provides an excellent window of opportunity to add cover crops to your cropping system. Mid-summer is the perfect time to get into the fields and add some diversity to your post-wheat harvest regimen. This time of the production season is where most fungicide disease applications are complete in other grain crops such as corn and soybean, and producers are working on their wheat fields following harvest by conducting field maintenance and straw harvest. Adding a fall and winter cover crop to your to-do list is an excellent addition to your fields, with numerous benefits.
The following information from Michigan State University Extension hightlights the benefits of this management practice and provides suggestions for incorporating cover crops after wheat into your system.
Fall cover crop benefits
First, let’s highlight some of the benefits of incorporating cover crops into your production following wheat.
Soil health and fertility
Planting a cover crop after wheat is a great way to improve soil health by putting fresh, green beneficial plants into what would otherwise be a weedy or barren field until the next season. Field preparation work following wheat will take place, so why not reap the benefits of cover crops in your fields while you are preparing for your next cash crop anyway? For example, planting leguminous cover crops like clovers, hairy vetch and winter peas will fix nitrogen, boosting your soil fertility.
Weed suppression
Arguably one of the most important benefits to cover cropping after wheat is weed suppression. Late season weed flushes or weeds that had been growing below the canopy of wheat can be problematic. If these weeds are left to mature and produce seed, this can create weed control problems in the future by increasing weed seed bank of the field. Soil wants to be covered, and cover crops provide that cover and in turn suppress problematic weeds from establishing and reproducing.
Prevent soil erosion
Cover crops have the added benefit of covering the soil to protect the soil fertility you’ve worked so hard for as a farmer from the harsh Michigan winters and tumultuous springs. Living roots in the soil helps keep the soil in place and protects the soil from erosion. There are some cover crops that winter kill, meaning they will die when hard frosts occur late in the fall. This is still beneficial because the roots will remain in tact in the soil and provide holding capacity for the soil against the elements.
There are also some cover crops like cereal rye that do not winter kill. Cereal rye will remain dormant in the winter and begin growth in the spring creating a lush, green landscape for your field that can be mechanically or chemically terminated prior to planting. The benefit to having a crop like cereal rye in your fields in the spring is that it provides ground cover for early season weed control and it can also help excessively wet fields by taking up moisture from the soil. Grazing livestock in spring cereal rye fields provides an excellent early season forage as well if that is a part of your system.
Cover crop options following wheat
There are a few good options for producers to get started with incorporating cover crops into their systems following wheat. This is in no way a definitive list, but some of these options are great to start with to see what works best on your farm.
Red or berseem clover
Red clover and berseem clover can be planted after wheat harvest, and red clover can also be frost seeded early in the spring (March). You can also drill the clover directly into the wheat stubble in August, just be aware of the soil moisture levels and how dry of a summer it has been. Clover growth and germination may be lackluster if conditions are too dry.
Berseem clover is a newer option and has shown some tendencies to be more reliable for summer planting following wheat, but the cost of berseem can be higher than red clover. Clovers have great nitrogen fixing capabilities, which is especially a great option if you are following wheat with corn the next year. Target seeding rates are between 5-12 pounds per acre (lbs/A) with a cost between $17.50 and $42 per acre.
Radish and oats
This is a popular option among growers, especially sugarbeet growers who have wheat in their rotations. Growers who have compacted or heavier soils also like this mix because the radish helps break up these fields.
There are two main types of radishes you’ll see in crop mixes: oilseed radishes and Daikon radishes that are also known as tillage or forage radishes. Oilseed radishes grow large and have weed suppression capabilities. Daikon radishes grow very large and are edible.
This mix will winter-kill, with the end goal of having a nice, clean field for spring planting. Target seeding rates are 30 lbs/A for oats plus 3 lbs/A for radish, with an approximate cost of $20 per acre. The Midwest Cover Crop Council and Michigan State University Extension have an excellent factsheet on integrating a cover crop like radish and oats into a wheat rotation: Michigan Cover Crop Recipe – Post Wheat, Going to Soybean or Corn: Use Oats and Radish Mix.
Soil building mix: 5 lbs/A annual ryegrass, 3 lbs/A crimson or berseem clover, 1 lb/A rapeseed or canola
This custom mix is an excellent option to fully cover the soil as the annual ryegrass does a great job of spreading and filling in the spaces of the field. A special consideration with annual ryegrass and rapeseed is that they can be tough to control with herbicide. If you spray annual ryegrass too early before adequate growth has occurred early in the spring, termination can be unsuccessful. Wait until the crop has put on good growth and temperatures are warm before terminating with herbicides.
Also, be aware that tank mixing some residual herbicides can reduce the efficacy of glyphosate when trying to terminate annual ryegrass. The Cover Crop Termination bulletin from Michigan State University Extension ranks the efficacy of various burndown programs on annual ryegrass, along with other cover crop species. If annual ryegrass persistence is a concern, an effective substitute would be winter barley at 15-20 lbs/A for easier termination compared to annual rye or rapeseed.
Summer biomass optimizer: Sorghum x sudan
If your goals are to build and add biomass to your field, incorporating sorghum sudan grass is an excellent option. You can use this as a base and add other diverse species into the mix to meet your production goals. For example, you can add millet, sunn hemp and legumes like cowpeas or forage peas. Adding nitrogen at 30-50 lbs/A when seeding the cover crop would help facilitate growth to achieve maximum growth if your goals are a forage crop or maximum biomass. Target your seeding rates at 10-20 lbs/A with an approximate cost of $15-$30 per acre.
Custom mixes
The fun part about cover cropping is you can be creative and strategic to create a mix that helps you achieve your own farm goals. A custom or “cocktail” mix can be created with a big diverse mixture of species. Seed supply stores can assist with the creation of custom mixes based on your goals. For example, forage mixes, soil building mixes or weed suppression mixes. You’ll have to experiment with seeding rates to meet your own budgets for cost per acre with a balance of achieving the desired effect in the field.
Planting considerations
Once you’ve decided on a crop variety with your intended goals in mind, there are a few important considerations regarding planting. First, seeding rates do not necessarily need to be full rates or recommended rates, but for best results you’ll want to target the recommended range of seeds per acre. This is especially true if your goal is weed suppression in a particularly stubborn field with a history of high weed pressure. In this case, seeding a full rate or at the upper end of the recommended range would be best to ensure full coverage of the crop to suppress weeds.
Conversely, if your goal is to add additional diversity and experiment with variety, you can cut back on the seed rate slightly to achieve the desired effect. This will save you money as you dial in what works best in your fields and at what seeding rate.
Environmental conditions will affect quality of germination and initial stand just like if you were seeding a cash crop. One challenge you will have if you are seeding in the mid- to late summer is ensuring uniform germination if conditions have been dry or hot. If you are late to your field following wheat harvest and weeds have begun to grow, cover crop establishment could be a challenge due to competition with weeds. Herbicide or mechanical cultivation can be used to make quick work of weeds and provide a well-prepared seed bed for effective stand establishment. Seed following this process as quickly as possible to give the germinating cover crop time to compete with any weeds that are germinating as well.
It is generally recommended that cover crops after wheat should be planted and incorporated into the soil instead of surface spread due to environmental conditions like dry weather in late summer. Grain drills and seeders work great, especially if you are planting into wheat stubble that has not yet been cultivated. If you are working with a cultivated bed and there is minimal debris or stubble, you can surface broadcast seed, but use surface tillage over the seeded field to ensure good seed to soil contact.
Seeding depth can be important for some species, especially the small ones that won’t emerge if seeded too deep. If you broadcast seed, increase the seeding rate to help compensate for poor emergence, especially if dry conditions are present. Just like our cash crops, timing plantings with moisture events or irrigating will ensure good germination and uniform crop establishment. This can be a challenge in August where we seed during hot and dry conditions, so keep this in mind as you plan your planting.
The benefits of cover cropping after wheat are numerous and can offer a solution to a multitude of field problems producers would like to address. Soil fertility and soil building, weed suppression, erosion protection and pest management are all possible with the right cover crop mixture. Although cover crops are not a “cure-all,” keep in mind that you will need to experiment with various factors of production to find what works well for you with your equipment and in your fields. This includes seed rates, seed varieties, planting timings and equipment used, which can all take time.
Do not get discouraged, and keep incorporating cover crops into your fields and production systems. The benefits will surely outweigh the costs, and the extra effort to add diversity into your cropping system will have your fields reaping the benefits for years to come.
For more information on cover cropping, visit the Michigan State University Extension Cover Crops website. The Kellogg Biological Station Long-Term Agroecosystem Research has been leading the study of sustainable agriculture production and cover cropping systems and is also an excellent resource.
