Why do farmers plant cover crops?
Posted: December 31, 2012
At this time of year, there are two reasons for this. Either the field has a terrible weed problem or the farmer has planted cover crops. In Franklin County, we generally see more cover cropped fields than fields with terrible weed problems.
Farmers are providing benefits for both themselves and for the rest of us in Franklin County by planting cover crops. Therefore, the more you know about cover crops, the better you can understand what these benefits are for you, the farmers and the soil. For those of you who have not heard about cover crops before, the Natural Resources Conservation Service (NRCS) defines them as “crops including grasses, legumes, and forbs for seasonal cover and other conservation purposes.” Not only do cover crops provide seasonal cover, which provides many environmental benefits over the winter, they also can add vital nutrients back into the soil.
Some of the cover crops you may see growing right now in Franklin County are cereal rye, winter wheat, spring oats, forage radish, and legumes such as hairy vetch and red and crimson clover. As you travel across the county, you will notice that fields with cover crops will look “prettier” than bare muddy fields with nothing planted because most of the cover crops will stay green throughout the winter. However, two of the previously mentioned cover crops, forage radishes and oats, will not remain green throughout the entire winter season because they die-off as soon as the temperatures get colder (i.e. winter-kill). In fact, the only evidence you may see of these two crops in the spring are a small amount of crop residue and some holes in the soil where the radishes were growing before they died off and decomposed.
As previously mentioned, cover crops provide huge benefits for soil health and water quality by providing seasonal cover throughout the winter. One of the most obvious benefits to planting cover crops that you can actually physically see in the county is the reduction of soil erosion. After a normal rainfall, the surface water running off of established cover crop fields does not appear to be as muddy as surface water running off of bare fields. This is because the cover crop plants lessen the impact of raindrops (so they have less of a chance to take the soil with them) and slow down the speed of surface water flow, while the roots help hold the soil in its place.
Another benefit that legume cover crops, such as hairy vetch and red clover, provide is that they can actually “fix” nitrogen, meaning they can take nitrogen from the atmosphere and put it into the soil. This is extremely important because farmers can rely on the nitrogen from cover crops to grow the next season’s crop, rather than spending money to purchase traditional fertilizer. Not only do farmers save money on fertilizer costs by utilizing the existing nitrogen, but they are also helping to lessen the potential of nutrient runoff which could eventually make its way to the Chesapeake Bay.
For those of us with home gardens, we might be able to learn a thing or two from the farmers about cover crops. Of course, home gardens are typically much smaller in size than average crop field, but the same needs and concerns for growing crops apply. You probably do not want to see your valuable topsoil wash away and, if you could spend less money on fertilizer in the spring due to a cover crop, that would be ideal, just like it is for the farmers.