The Conservation Capacity Building Initiative was created in response to the Illinois Nutrient Loss Reduction Strategy (NLRS) to promote conservation practices throughout the state. The goal of this publication is to spread awareness about conservation practices and programs that will assist farmers and those who advise them in decreasing nutrient losses while also improving their yields. Each month we will feature a Frequently Asked Question about soil
health and present information and resources from some of the key stakeholders involved in this initiative. For more FAQs, resources, and upcoming events, please visit our AIM Soil Health page.
A common question about soil health is regarding the importance of cover crops. When deciding to plant cover crops, there are a few things to take into consideration: identify goals and species selection, planting methods and establishment, management and termination, and financial considerations.

IDENTIFY GOALS & SPECIES SELECTION

Think about your crop rotation and what you are wanting to achieve. Whether it is weed
control, reducing compaction, or nitrogen fixation, each species has unique benefits. The
Midwest Cover Crops Council has a very helpful tool that identifies which species may work
best based on your location, cash crops and personal goals. It is also important to consider which nutrients your cover crop will require compared to which ones your cash crop will need. If rye reaches maturity, for example, it can tie up nitrogen in the soil that would be needed by corn. The Illinois Nutrient Research and Education Council (NREC) has a very helpful guide on how to get started in cover crops, including planting and termination methods, best practices, and information on how they can reduce nutrient losses in soil. NREC and Precision Conservation Management (PCM) both recommend starting with cereal rye ahead of soybeans. PCM published a case study based on data from ten of the most profitable Illinois corn/soybean farms in their program using cover crops, and they found that choosing an effective species is more complicated ahead of corn, but progress is being made in this area. It is generally recommended to start small with just one or two species while figuring out what works for your operation.

PLANTING METHODS & ESTABLISHMENT

Once you have selected which species you want to grow, the Illinois Sustainable Agriculture
Partnership (ISAP), which also formed in response to the NLRS, has created a Cover Crop Seed Dealers Directory. ISAP also has a very useful guide on cover crop seeding methods. No matter which method you’re using, adequate moisture is required to for cover crops to successfully establish, and they should be watered regularly for the first 2 to 4 weeks. Cover crops are vulnerable to drying out until they reach 4 to 6 inches tall. Timing varies based on your planting method. For example, when aerial seeding into soybeans pre-harvest, be sure the leaves have not yet fallen, which would prevent seed to soil contact. Certain residual herbicides may also interfere with cover crop establishment. Researchers at the University of Wisconsin-Madison found that herbicide carryover injury is dependent upon weather conditions, application rate, and cover crop species. Their 2013-2014 study provides a chart of which common corn and soybean herbicides negatively impacted winter rye, radish, crimson clover, annual ryegrass, and an oats/peas mixture when applied at full-label rate at the latest application timing. They noted that in 2014, a year that saw more precipitation and warmer temperatures, little to no carryover injury was observed.

MANAGEMENT & TERMINATION

Mowing certain grass cover crops and allowing them to regrow may be helpful in enhancing
the depth of the root systems, thereby maximizing nutrient recovery. In general, cover crops
should reach 50-75% of the flowering stage before termination. This is when they tend to provide maximum benefits like adding nitrogen to the soil or breaking up compacted ground. Some species like oats and brassicas are winterkill, which means they will die on their own when the temperature gets low enough. With other species, the longer you can wait for termination, the better. Just be sure to terminate before they go to seed. It is generally recommended to terminate a couple weeks before planting your cash crop. The primary termination methods for larger acreage are herbicide and crimping. According to the NREC guide, cereal rye needs to be in the reproductive stage for crimping to work effectively. Some methods for smaller acreage include mowing and/or silage tarping, but mowing is not always effective on its own, as many species will grow back.

FINANCIAL CONSIDERATIONS

USDA-NRCS has a tool for calculating the economics of investing in cover crops, including estimates on how much money the benef its will save over time. There are many payment opportunities available to help with covering the cost. ISAP has assembled a Cover Crop Incentives Directory, which includes a stacking matrix to help farmers navigate their eligibility when applying for multiple programs. Each program has unique criteria that must be followed. USDA-NRCS has its own conservation practice standard for cover crops, and their programs include Environmental Quality Incentives Program (EQIP), Conservation Stewardship Program (CSP), and Regional Conservation Partnership Program (RCPP).

This article was originally published in our October 2024 Newsletter, click here to read the full news letter.