Myth Busting Cover Crops

Over the last couple of weeks as I’ve been out and about at different community events or just visiting with fellow farmers, the topic of regenerative ag has been a common theme of discussion. For our area in south central Minnesota, we are one of very few farmers that embrace regenerative ag. Over the last several years, we have made the transition to using cover crops on the land we farm. We primarily plant cereal rye as our common cover, but because we are one of few in our area, we strive to educate and talk about what we’re doing because it works for us, and we believe in the practices!

Because cover cropping isn’t a widely “accepted” agricultural practice in our neck of the woods (yet!), there are often questions and myths that arise in conversations. As I’ve talked with more and more people (both in and outside of agriculture) over the last few weeks about what we’re doing on our farm, it got me thinking that I should bust some common cover crop myths!

Here are five common misconceptions about cover crops, debunked!

There will be interference with cash crops.

This is probably the most common myth out there when it comes to cover crops. Farmers have a lot of acres to plant in the spring and time is always of the essence! In a 2019-2020 National Cover Crop Survey conducted by the Conservation Technology Center, farmers that utilize cover crops were actually found to plant earlier following that cover because of an improvement in field conditions.

I have to say that we saw this come to fruition in 2019 when we had an incredibly wet, moisture filled spring and growing season. At that time, we were working through the transition to cover crops so we did not have them on all of our fields. We weren’t able to get all of our acres planted because of the conventional tillage practices used, but the fields that had an established standing cover, we were able to plant.

On established fields, we plant “into the green” so we do not terminate the cover before planting our cash crops of corn and soybeans. We later terminate the cover by spraying it dead (future blog post?) after planting, but before the cash crop canopies. We also seed some cover in the fall so it becomes established, and if it grows enough, we either turn our cattle out on it to graze (a very efficient way to feed animals because they also spread their own fertilizer!) or we harvest it by cutting and baling it to later feed to our cattle throughout the winter.

The transition to cover cropping was a learning experience and we have had to adjust our nitrogen applications year after year to ensure our corn receives the nutrients it needs to grow and yield at harvest time. We have also avoided yield decreases by matching the cover crop life cycle and nutrient output to the cash crops. We took a holistic approach as cover crops have allowed for input efficiency, as well as improved productivity (easily a 3-5% yield increase) in the long term due to the soil health improvements.

Bigger yield benefits from cover crops are likely to be seen in dry years (again can testify to this in the 2021 drought!) and sometimes in excessively wet years because cover crops improve soil resiliency.

Water availability will be reduced.

A long time ago, there were big concerns about cover crops using too much of the ground moisture, thus reducing the water availability for the subsequent crop. Because of the improvements to soil resiliency, this concern is really no longer relevant. The diverse root structures that cover crops provide aid in water and nutrient circulation which helps the soil drain. Higher levels of organic matter in the soil also act as a sponge that locks in moisture.

Cover crops are also incredibly beneficial when it comes to building soil structure and “internal” drainage systems (with their roots). Their root systems create channels for moisture to flow deeper into the soil, which minimizes run-off.

New pests will be introduced.

With every introduction of a new species in a field, there is always the concern of attracting new pests. Depending on the regions, pests of concern include slugs, voles, and “green bridge”.

In certain regions, crop residue (leaves, stems, pods, etc.) provides an ideal environment for slugs and voles. One way to mitigate this is to terminate the crop cover at planting of the cash crop or shortly after. Adjusting the use of insecticide treatments also allows for more ground beetles, which act as a natural control agent for slugs. A natural control agent for voles is prey birds, so we welcome wildlife to help mitigate pests too!

Probably one of the biggest concerns regarding pests is the idea of a “green bridge”. This is the idea that an insect or plant disease may feed on the cover crop and then move to attaching the emerging cash crop. Early indications in research have shown that there is less of an issue with insects jumping from the cover to a newly emerging crop if termination happens shortly after or immediately before planting the cash crop.

Soil temperatures will remain too cold.

There is a myth that cover crops keep the soil from warming up at the same rate as tilled black dirt. I’ve been told that black soil warms up faster because the sun hits it directly, whereas dead crop residue in a no-till system can keep soil temperatures cooler in the spring. However, once cover crops are introduced, it is a whole new ball game. Cover crops are a living and growing substance in the ground that actually creates a respiration system, generating energy. This extra energy in the living cover crops and active soil microbial system usually leads to soils that are comparable in temperature to tilled fields.

Pollinators will be fed.

Cover crops can provide a habitat for pollinator insects, but for pollinators to have food, they need plants that are allowed to reach the flowering stage. Most of the time, cover crops are terminated before they reach flowering, but as of recently, farmers are seeing the benefits of letting covers grow longer which allows them to at least briefly reach the flowering stage before termination.

If the goal is to provide a thriving habitat for pollinators, then we would look at more biodiversity in the field. Sometimes this is accomplished around the field borders, or scattered throughout the entire field. Instead of planting just cereal rye, a farmer could plant a multi-species cover crop “package” that provides pollen sources throughout the summer and into fall. Multi-species help speed up the process of soil health improvements too!

Using cover cropping practices does take strategic implementation. But when done right, cover crops can build organic matter, improve soil structure, combat erosion and soil compaction, fix notable amounts of nitrogen, increase water holding capacity, etc. The list goes on and on! Addressing field challenges with cover crops does take time and patience, so we consistently work with our agronomist to figure out what plan of action is best for each of our farms.

As spring continues on and the weather warms up, our fields will start to turn green. This to me is such a welcome sight after a long winter! Subscribe below to make sure you get in on all of the regenerative ag updates we will have coming as we start planting in hopefully a few weeks!

Rooted in ag and led by faith,

Ellyn