Get Started on Simple Summer Cover Crop Strategies

by Margit Kaltenekker, Agriculture Agent for K-State Research and Extension Douglas County

Summer is the perfect time to think ahead and plan your Cover Crops strategy for this fall. Cover crops are foundational to building Soil Health. Cover crops provide armor to the soil after termination, naturally suppressing weeds through a dead mulch; they add green cover and living roots between cash crops, reducing wind and water erosion over winter; in the process they increase soil organic matter and nutrient cycling, offering the potential to reduce inputs and increase yields. Cost-share opportunities are offered through our local WRAPS programs depending on which watershed you farm in.

There are multiple management options and cover crop varieties that can at first appear overwhelming. In learning to manage cover crops for greatest benefit to soil health and maximum crop yields, in a manner that reduces inputs, there are three simple considerations to follow: Seed Early, Plant Green, and Terminate by Roller Crimping.

Part 1 aims to discuss the first step: Seed Early with additional resources provided.

As with all agricultural practices, timing is everything. Commonly – winter rye is seeded far too late after soy or corn harvest in October, to get the greatest benefit of winter growth and biomass. While winter rye is cold hardy and will eke-out a green crown by December, the roots are unable to capture many of the excess nutrients leaching into the deeper layers of soil after the cash crop.

North Central Soybean Research program shared an article discussing research by Dr. Ray Weil at the University of Maryland. The research shows winter rye and other cold season covers sown a month earlier (mid- August/ mid- September) and terminated later in the spring, gives these covers more time to build biomass, root deeply and work their magic in the soil within a soy-corn-soy or corn-soy-wheat rotation. Choose earlier soy and corn varieties, to facilitate earlier cover crop seeding dates. Earlier seeding dates using aerial, broadcast application, or no-tilling over the crop gives much more time for root growth to capture unused nutrients and penetrate deeply, bringing up macro- and micronutrients.

With soy, start to sow the cover crop when the canopy starts to yellow…while pods are still tender before senescence. With corn, new technology provides a way to drill cover crops in mid-July, with a side-dress nitrogen application. Corn allows enough light to penetrate the canopy to start a cover crop that will take off in late summer and hang on through winter.

Plan to use a simple three-way mix: a grass, such as winter rye or oats; a legume - such as red or crimson clover, hairy vetch, or Austrian winter peas; and a brassica such as rape or winter radish in varying proportions depending on which crop its following. Over or interseeded soy (ahead of corn), many producers prefer oats for a winter killed mulch; Weil found clover and brassicas also to do well in soybeans. Sowing into or after corn, (ahead of soy) uses heavier rates of winter rye and brassicas that penetrate deeply, lighter on the legumes. Adding a winter radish with legume helps the legume grow more vigorously according to Weil. Companion planting provides synergistic effects that are not fully understood, but observations prove the difference is significant.

The Midwest Cover Crops Council is a great resource with a Row Crop Selector Tool and other reliable articles for incorporating cover crops into your cropping systems.