1 of 18

COVER CROP PLANTING�AND ESTABLISHMENT

COVER CROP

TRAINING MODULE

2 of 18

Developed by

Dr. Rob Myers, University of Missouri and NCR-SARE

Reviewed by

Dr. Eileen Kladivko (Purdue University) and Dr. Paul Jasa

(University of Nebraska)

Funded by

Walton Family Foundation

These training modules are being made available by free use of other educators through University of Missouri and the Midwest Cover Crops Council, which participated in the WFF project supporting development of these modules and provided many of the technical reviewers.

All photos are by Rob Myers, University of Missouri, unless otherwise noted.

3 of 18

Presentation Outline

Type of seeding method used
Equipment options
Timing of seeding
Interseeding options
Avoiding problems with residual herbicides
Impacting survival of winter annual cover crops

4 of 18

What Planting Method Will Be Used?�

Traditionally, most cover crop seed has been drilled or broadcast-seeded. When broadcasting:

- the larger the seed, the harder it is to get good seed-soil contact, so more important to rough up the soil surface, and possibly roll or press the seed into the soil after broadcasting

- aerial seeding works best with smaller seeded cover crops like radishes, clover and ryegrass than large seeds like Austrian peas

Precision planters (like a corn planter) can work well for one or two species but not as well for multi-way blends of cover crop seed
Planting method will often be tied to planting date, and some species are more important to plant early in fall (like radishes) than others (like cereal rye)

Key thing here is that some cover crop seed, generally smaller-seeded species, are easier to broadcast establish than others. Large-seeded cover crops like Austrian winter peas are difficult to establish by broadcasting because their large size prevents good seed-to-soil contact and they don’t imbibe the moisture needed for germination. If a medium-large seed like oats will be broadcast, a rougher soil surface may allow the broadcast seeds to nestle into the soil surface, especially after a rain, and have better germination.

Small seed, particularly rounded seed like clovers, radishes, and rapeseed, do a better job of rolling down into cracks and crevices in the soil surface and finding enough soil contact that they can germinate, assuming the soil is already moist or a rain comes in a timely fashion.

It’s good to point out that all cover crop species benefit from good seed-to-soil contact, which means using a planter of some type is better than just broadcasting the seed on the surface.

5 of 18

Reliable Cover Crop Establishment:�Use a Grain Drill

6 of 18

Row Crop Planters and Cover Crops

Photo credit – Rob Myers

Depending on the cover crop being planted, some farmers have switched to using their row crop planter for seeding cover crops. Sometimes this is because they don’t have a grain drill, other times because they want to cover more acres (row crop planters are often wider than grain drills). Or they may feel they can achieve a lower seeding rate and thus have less seed cost compared to a drill, because the row crop planter can more precisely meter out the seed.

However, many cover crops provide better soil erosion protection and winter annual weed suppression if planted in narrower rows such as offered by a grain drill. A row planter than can do 15 inch wide rows may be a viable alternative in some situations, but generally a row planter set to 30 inch row spacing would not provide very adequate soil cover.

Another possible downside to a row crop planter is wearing out expensive disk openers or other parts that may need to be replaced more often than on a grain drill.

7 of 18

Vertical Tillage Tools with Seeders

Photo credit – Rob Myers

Another option for getting some incorporation of broadcast cover crop seed is through use of a vertical tillage tool. Since many farmers are already doing a vertical tillage pass in the fall, several of the companies selling vertical tillage units have started offering cover crop seeder add on kits. These all have a similar approach, adding a seed box with an air blower unit and seed distribution tubes on top of the vertical tillage frame. Most have the seed broadcast in front of the vertical tillage unit, a few do it at the back.

Broadcasting seed in front of the vertical till unit can work well for cover crop seed that can tolerate being an inch or more deep, such as cereal rye, triticale, winter wheat, oats, and Austrian winter peas. However, this method can end up planting some types of cover crop seed too deeply; radishes, rapeseed, clovers, and other small seeded cover crops generally will do better planted at a half inch depth or less. Those may provide a case for broadcasting the seed at the back end of the vertical till unit.

Use of a cover crop seeder with a tillage tool may seem at conflicting odds, since the ideal system is to combine cover crops and no-till. However, the fact is many farmers are not yet ready to give up at least a modest amount of tillage, such as running a single vertical tillage pass (which does leave a fair amount of residue intact). Applying the cover crop seed in the same pass as a tillage action that would be done anyway, makes the cover crop seeding very affordable and time efficient for the producer.

8 of 18

A Variety of Cover Crop Seeders Now Available

9 of 18

Every Day Counts With Fall Cover Crop Seeding

Photo credit – Steve Groff

10 of 18

Oct 7 vs. Sep 29

Picture taken November 11 by Steve Groff, PA

Planting date can make a major difference in getting adequate fall growth out of a cover crop. The greater amount of heat units available in early fall will cause most cover crops to get off to a fast start. In late fall, many potential cover crops are slow to emerge and may get little visible growth. Also, winter survival of the cover crop is often affected by planting date. Cereal rye can tolerate a late fall planting date but most other cover crops will not survive a hard winter if planted too late in the fall.

Cover crop species that need to be planted particularly early include most of the Brassicas, like radishes, turnips, rapeseed/canola, kale, Ethiopian cabbage, etc. Legumes like clovers, vetches, and Austrian winter peas can be planted more mid-fall, but will get much better fall growth if planted in early fall. The cereal grasses can be planted latest, particularly rye, but even with those species, fall growth will be much better if planted by mid-fall than late fall.

Even a difference of a week can make a big difference in fall establishment, as pictured in this photo from Pennsylvania. Farmers should have a plan to get the cover crop seeded as soon as a field is harvested; many experienced cover crops will have an individual running a grain drill with cover crop seed right behind the combine, not even waiting a day. Others will interseed into the standing fall crop prior to harvest to give the cover crop a chance at an earlier start; however, this broadcast method can itself lead to establishment delays if timely rains do not come. Drilling or other direct planting of the seed generally leads to best establishment success.

11 of 18

Seeding Cover Crops while Combining

Photo credit – Rob Myers

One option for combining trips across the field is seeding cover crops while combining. In this photo, a Gandy seed box specifically manufactured for attachment to combine heads is attached to the corn heder. The Gandy unit includes a seed box, an air blower shown on the side of the box, and tubes that direct the cover crop seed down underneath the header. The seed is broadcast before chaff is blown out the back of the combine, allowing for better seed to soil contact.

Such units can work fairly well, but some farmers who have tried them have commented they don’t like slowing down the harvesting process to stop and fill the cover crop seeder. A cover crop with a low rate of seeding, such as radishes or rapeseed, may be a better option for this approach than something like rye or oats that require a lot more seed per acre (about 50 pounds/acre or more versus just a few pounds/acre for radishes or rapeseed).

12 of 18

Getting Cover Crops Seeded Earlier

Von Tillburg farm (Ohio)

Hagie Cover Crop Interseeder

Photo credit – Rob Myers

13 of 18

Successful Aerial Seeding

Key factors:

Timing: wait till cash crop is turning color
Seed type: small seeds better
Use a pilot skilled with cover crops

Photo credit – Rob Myers

14 of 18

Options for Planting Mid-Summer

Interseeding cover crops in knee high corn – can give them an early start BUT must adapt herbicide program. Success depends on rainfall and cover crop species.

3-in-1 option:

Seed covers
Apply liquid N
Spray for weeds

Interseedertech.com

Photos here are from Interseedertech.com. This company was developed by Penn State University faculty who collaborated to develop a high clearance drill modified to be driven over corn at up to the V7 stage, or could be used with other row crops.

This particular high clearance drill is available in a couple of different widths and is called 3-in-1 because it can do up to three things in one pass – seed the cover crop, spray a post-season herbicide, and apply liquid side-dress nitrogen (or any liquid fertilizer).

This approach has to date been more popular in the northern Corn Belt than southern, especially in the northeastern Corn Belt. It’s success relies on having enough rainfall to support the small cover crop seedlings which otherwise struggle to stay alive in competition with the much bigger corn crop.

Other keys to success with this approach are adjusting the herbicide program to allow use of the relevant cover crop, and selecting an appropriate cover crop species or mix that can tolerate shade and work with the herbicides being applied. Annual ryegrass has been one of the better shade tolerant options. Some of the clovers seem to work adequately. Experimentation is probably a good idea to determine what works for local conditions.

This is a viable way to give cover crops a much earlier start than drilling after harvest.

15 of 18

Other Cover Crop Planting Tips �– Avoiding Residual Herbicide Issues –

Residual herbicides can have a big impact on success in getting cover crops established:

Plan ahead to make sure residual herbicides are compatible with cover crop being planted
Cereal rye tolerant of most residual herbicides
Brassicas such as radish, turnip, and rapeseed tend to be most sensitive to residual herbicides, especially those with broadleaf activity
Weather conditions will affect how long residual herbicides persist in the soil

16 of 18

Getting Winter Annual Cover Crops�to Survive the Winter

If goal is getting cover crop to survive till spring:

Plant in a timely fashion; some cover crops must be in by early fall to have a chance of surviving the winter
Match the cover crop to the soil; some species less tolerant of poorly drained conditions, such as Brassicas and some clovers
Seeding rate can impact survival, especially on Brassicas; don’t overseed them
Having some residue cover or a companion cover crop can help less hardy species survive (like oats with clovers)

17 of 18

Getting started with cover crops� –> Plant cereal rye before soybeans

LGseeds.com

Photo credit LGseeds.com

A good first step for most Midwest farmers considering cover crops is to plant cereal rye before soybeans. The rye provides many benefits and works very well in combination with soybeans. There is generally enough time to get the rye planted after corn harvest. While drilling the rye is preferable, many farmers have obtained reasonable stands of rye by broadcasting the seed, either with an airplane, fertilizer spreader, on a vertical till tool, or other methods. The rye can be terminated early before the beans, or the soybeans can be “planted green” into the still living rye, and then the rye can be terminated with herbicide or a roller crimper.

The Midwest Cover Crop Council has simple 2-3 page recipe guides on getting started with cover crops for each Midwestern state, and all of them recommend cereal rye before soybeans. The guides contain seeding rate and method recommendations and tips on termination and other management. See: https://mccc.msu.edu/getting-started/cover-crop-recipes/

18 of 18

Summary on Establishing Cover Crops

Getting the cover crop seed established at the appropriate time is key to getting optimum benefit from the cover crop and increasing the likelihood of winter survival
Successful establishment depends on good seed-to-soil contact and having the cover crop seeds receive adequate moisture, either from being planted down into existing soil moisture or receiving timely rainfall or being irrigated
Seeding the cover crop before harvest of the cash crop is increasingly an option for many farmers
If farmers are short on time, hiring an ag retailer, aerial applicator or neighboring farmer to do the seeding can be viable