Essential cover crop planning checklist: Boost soil health this fall

Fall cover crop planting is just around the corner. Cover crops address various problems in your field while providing soil health benefits so it's important to start off on the right foot. The question at the top of everyone's mind right now is what it takes to achieve a successful cover crop stand.

Some problem areas that may be addressed by cover crops:

• Limits early season weed germination.
• Reduces soil erosion or gully formation.

Some benefits that may be provided by cover crops:

• Supplies nitrogen for the next corn crop.
• Increases soil organic matter.

Your journey begins by determining a primary goal for your cover crop. Setting this goal is crucial in guiding your entire planning process and can help you better evaluate the success of your cover crop. Once you've established your goal, consider these five points before you plant the cover crop:

1. Select an adapted cover crop species that fits your needs.

Choose cover crop species that align with your goals and system constraints using tools like the Midwest Cover Crops Council row crop tool to help you sort out species attributes. Consider how the cover crop complements your existing rotation such as:

• Higher biomass cover crops before soybeans to limit weeds until canopy closure.

OR

• Legumes and brassica species that decompose quickly to provide some nitrogen release to a corn crop.

Plan for the next cash crop by deciding on a cover crop termination strategy and acceptable cover crop residue levels for planting cash crops. You can also evaluate the tolerance of the selected cover crop species to herbicides that have been applied to your previous cash crop, especially in drought conditions (see the table in the Effect of residual herbicides on cover crop establishment). Remember that these residual herbicides break down more slowly during droughts and they may harm cover crops in drier years like this one.

^{Figure 1: Choosing a primary crop function is the first step toward reaching goals. Photo from https://www.sare.org/publications/building-soils-for-better-crops/cover-crops} 

2. Manage cash crop residue to ensure good cover crop planting conditions.

Adjust combine settings to spread residue evenly and broadly after harvest. Uneven residue can inhibit cover crop germination and root establishment.

A good rule of thumb: The width that residue is spreading out of the back of the combine should be the same as the width of the combine header. Check out the Conservation Cropping Systems Initiative Podcast discussing combine residue spreading impacts.

For deep residue, consider planting a grass cover crop component. Legumes should be drilled to ensure good seed to soil contact for the survival of symbiotic rhizobacteria in seed coatings.

^{Figure 2. Residue spreading width should match combine header width. Photo from https://www.farmprogress.com/corn/8-tips-for-better-residue-management}

3. Make adjustments based on soil moisture.

Consider delaying planting until moisture is expected since many areas are currently experiences moderate to exceptional drought conditions. Dry conditions reduce the chance of successful establishment, so it may be better to skip the expensive species like radishes and choose more affordable options such as locally available wheat.

4. Plant selected species on time.

Choose the planting method that allows your selected species to be planted on time. This is critical for species susceptible to winterkilling such as oats and radishes, which should be planted 6-7 weeks before a frost. Shift to species that are more cold-hardy if planting is delayed. Cereal rye, for example, can be planted later than all other species.

5. Assess available planting methods.

Many areas require cover crops to be interseeded into unharvested standing crops to ensure enough growth before frost. Explore non-traditional options such as combine-mounted broadcast seeders or drones (Selecting Cover Crop Seeding Machinery). Note that aerial and broadcast seeding rates should be increased at least 10-20% compared to drilling rates. Legume species should generally be drilled to increase seed to soil contact. Large-seeded legumes like Austrian winter pea and vetch perform poorly when broadcasted and should be drilled.

Reach out to a Cargill agronomist as they can provide expert advice and tailored recommendations to help you develop an effective cover crop establishment plan.