By Clint Nester

We are quickly approaching the time to start thinking about fall cover crop options. In our business, we have seen some excellent soil health and erosion benefits from cover crops and encourage growers to take a look at the rewards cover crops can provide.

If you are just getting started, start small and don’t get discouraged. If you are a longtime cover crop user, try some new species and experiment with timing of termination. Whether you plan to interseed into a standing crop, or wait to plant until after harvest, there are many options and variables to consider.

Should I plant in-crop?
To maximize cover crop benefits, the cover crop must get established and get significant fall growth. To achieve a good growth, growers can interseed cover corps into a standing crop. With interseeding, you are limited to aerial application with a helicopter or plane, or one of several high-clearance seeders across the state. In our experience, these seeding options have provided variable results in regards to cover crop stands. However, earlier seeding dates have been showing promise with improved stands.

Weather, amount of moisture and frost dates also play a big role in stand establishment. A major benefit to interseeding is that since you are seeding at an earlier date, your cover crop variety options are vast. We recommend growers check out the Cover Crop Selector Tool from the Midwest Cover Crops Council. The tool does a nice job identifying suitable options that fit a grower’s unique situation. Location, previous crop, planting date, drainage and grower goals are all taken into consideration. When possible, we like to see growers use a mix or blend of cover crops for optimal soil health benefits.

What are postharvest options?
If interseeding isn’t an option, cover crops can be successfully planted following harvest. In our experience, a drilled or planted cover crop has resulted in excellent stand establishment. We have also seen good success when cover crops are broadcasted on the surface and lightly worked in with a vertical tillage tool. Many times we will add potash as a carrier. The downside here is that with a later planting date you are limited on varieties that will have enough time to get established.

In most years, cereal rye is probably your best bet for a postharvest cover. We have seen cereal rye planted in late November still get established and continue to grow throughout the winter before really coming on in the spring. We recommend that at least one species of your cover crop overwinters. Research has shown that in some instances a cover crop that winter-kills can bring nutrients to the surface, and expose them to potential runoff once the cover crop dies.

What about herbicides?
Whether planting in a crop or after harvest, be sure to review your residual herbicide program before planting your cover crop. We have seen many instances where a grower plants a fall cover crop and gets a very poor stand only to find out that his residual herbicide influenced his cover crop stand. The University of Wisconsin has put together a chart that shows herbicide rotation restrictions for cover crops.

What are some spring management considerations?
When terminating a cover crop ahead of corn we use the saying, “When in doubt, take it out.” This timing will depend on each grower’s comfort level, but if you are new to cover crops, we suggest terminating the cover crop at a small growth stage or about a month before planting. Many times this involves the use of an ATV sprayer due to the wet field conditions during spring. As you get more comfortable with cover crops and planting conditions, move the termination date closer to the planting date. If you plant into a green cover crop, be sure to scout for insects that may overwinter.

Ahead of soybeans, we have seen excellent results by terminating just before planting and planting into the standing cover crop. In 2016’s wet spring, many growers planted soybeans into 5 to 6 feet of ryegrass and experienced record yields.

What’s best for termination?
There are numerous herbicides that can be used to terminate cover crops. However, we have had good success with using full rates of nonselective herbicides, mainly glyphosate or glufosinate (Liberty). For optimum kill, we recommend spraying on a warm, sunny day. The growth stage at the time of termination can also be a factor in the effectiveness of the kill. We recommend terminating prior to the cover crop entering the reproductive stage for best success.

If you are an experienced cover crop user or thinking about trying cover crops for the first time, we encourage you to experiment and find what works for your operation. If managed correctly, there are many benefits that can come from cover crops. Start planning your fall cover crop now so you can reap some of the cover crop rewards.

Nester is certified crop adviser with Nester Ag LLC. Email [email protected].