Utilizing cover crops in our fields

2014 by Jason Tyrell

Cover crops have been around for many years in some areas; however it is rather new to others.

Importance of cover crops

Cover crops protect against topsoil loss from erosion, provide organic matter and utilize the unused nutrients in the soil while creating and generating more available forms of nutrients. Cover crops are very versatile and can be used not only as a soil protector and enhancer, but can be used also for livestock grazing and stored forage purposes. Without cover crops, soil health and soil structure would suffer and more applied nutrients would have to take place to add what was lost by not having cover crops on your fields.

Species Selection (Just to name a few):

Rye

Rye is one of the best cool-season covers for absorbing unused Nitrogen in the soil. It is very quick growing, which provides cover to avoid erosion due to rain and wind, while suppressing weeds. It also helps add organic matter as it supplies a great source of residue.

Rye does a lot to improve the soil where it is planted and has a very good root system to help hold the soil together; however, it does not do much for addressing compaction issues as it has no taproot.  One large benefit of rye is that it is able to be seeded later in the fall than most all other cover crops, while still performing at a high level for all of the positive notes listed above.  Since rye is such a large nitrogen scavenger, mixing it with a winter annual legume would retain some nitrogen for the spring. It will survive throughout the winter and regrow robustly in the spring. Ways to kill rye in the spring would be by cutting, spraying herbicides or tillage.

Winter wheat

Winter Wheat, typically grown as a cash crop, has the ability to serve a dual purpose as a cover crop, then as a grazing option in the spring. Wheat is slower growing, so problems such as overgrowth that you may have with rye in the spring, you shouldn't have with wheat. Wheat, as a cover crop, is good for erosion control, catching the nutrients currently in the soil and is good as a weed suppressor.

Legumes

Legumes add a great source of nitrogen into the soil.  Depending on the type of legume that you choose, some are more tolerant of heat and cold and moisture and some grow more rapidly than others. I suggest you research which type would be the best for your area. Some examples of legumes are alfalfa, alsike clover, birdsfoot trefoil, crownvetch, red clover, white clover and sweet clover.

Oats

Oats are a cool season annual that grow swiftly and provide great cover, which reduces soil erosion. If you do not want to deal with having to cut in the spring, oats are a great option, as they should winter kill, which actually helps the survival of legumes if they are in the cover crop mix. They have a very fibrous root system that holds the soil structure intact. Oats gather up the excess nitrogen and suppresses weeds as it out competes them.

Tillage radish

Tillage radish is a fantastic way to address a compaction issue. Radish provides good cover and prevents soil erosion while alive. Radish should winter kill and leave holes in the ground allowing for water and air to reach further down into the soil layers than they normally would. These holes also provide an easy pathway for future crops root systems to travel. Another positive of the radish is that they help drive away slugs. Tillage radishes have a very bad potent smell when they die. This could be a disadvantage for close neighbors.

Application method:

There are several types of applications styles that can be used for cover cropping. Some ways to get the seed down before the harvest of your current crop would be Air Seeding and Aerial Seeding. Air seeding is done with a “highboy” tractor and the seed is blown through dangling tubes into the ground. Aerial seeding is done via airplane.

Harvest?

If you plan to harvest your crop first, then a No-till application is a great option as it reduces the number of times you need to be out on the field, which reduces compaction and soil erosion. It is also a great way to assure solid seed to soil contact. Another way would be with a seeder used after the ground is run over with a tiller. This is a good way to incorporate good seed to soil contact while reducing the top soil compaction thanks to the tiller however it does allow soil erosion to become a problem before the cover crop germinates and grows.

Benefits to your soil health:

Top growth

With cover crops, it would absolutely be great to have solid top growth along with a solid root system, but it doesn’t always happen that way. Sometimes we don’t get the top growth that we wanted or were hoping for. One thing to remember is that just because the growth of the plant above the soil may not be good, the root system may still be flourishing.

Preventing erosion

Yes, it would be better to have that plant cover to prevent soil erosion from rain and wind, but sometimes it just doesn’t work out that way. What matters just as much, if not more is what is happening underground. Having a solid root foundation allows for better soil structure and a higher nutrient content. Earthworms are a great sign of good soil health. Soil is highly complex, so I won’t go into all the science of it today, but I will say that good soil health is absolutely essential to the growth and production of your crops.

All in all, cover crops are a great conservation practice that improves soil health and reduces erosion and compaction problems. Cover crops should not be over looked and landowners who have used them for years can tell you that they really are a great option for all types of farmers.

(Jason Tyrell is a district technician for the Guernsey Soil and Water Conservation District. He’s a graduate of West Virginia University with a degree in agricultural business management.)