Boosting Soil Health with Cover Crops

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soil health
Above: buckwheat, vetch, and oat are some good options when considering cover crops. Photo by Serafina Lombardi.
By Margaret Campos

All living things need nutrition and the soil of the earth is no different. Soil, not to be confused with dirt, is a living, organic element full of organisms, seen and unseen. The soil provides nutrients essential to plant growth  that, in turn, feed us. Thus, we should do the utmost we can to feed the soil properly.

During the autumn season, many of us begin to retire our efforts to work outside, but before you do, please consider that this time of year is one of your best opportunities to improve soil health by planting a cover crop.

Top soil is the portion of earth that is covered with decayed plan matter that is so vital to soil health. A cover crop serves to protect the fertile top layer of soil that you may already have. The cover crop will develop a network of roots that helps to stabilize the soil so that it cannot easily be blown away with those strong New Mexico winds.

Perhaps the most important function that a cover crop will fulfill is to provide vegetative growth so that in the springtime you can till the crop into the soil, allowing it time to decay, producing the nitrogen necessary for strong plant growth. The more organic matter in the soil the healthier it will be.

Before we dig deeper into cover crops, let’s first talk a little about what kind of soil you have and what else you might need. You can spend a lot of money testing your soil, or you can easily do a simple test to find out if your soils are sandy, clayey or loamy, with loamy soil being the ideal.

When the soil is damp (not wet), grab a clump of soil. If it sticks together, your soil may be clayey, which means you have to water less, but the soil may be lacking in proper nutrition. If the soil runs through your fingers or doesn’t clump at all, your soils are sandy, they will need to be watered often to hold moisture and are lacking in organic matter.

For both sandy and clayey soils you may need to apply manure to improve soil conditions. If you have the time, apply a good layer of manure before you prepare your field for planting cover crop. By allowing the manure a whole winter on the field, it will be safer for your plants. If you don’t have time this autumn, make sure you use composted manure when applying next spring; non-composted manure may be too hot and can actually burn your plants.

If  your soil is loamy, clumps together slightly, then you probably only need to plant cover crop to maintain your soil condition; if you plant a cover crop annually you may never need to apply manure. So my choice is to spread seed versus shoveling poop!

There are some good options for quick growth crops that will be ready to till under early in the spring. Winter wheat, hairy vetch and red clover are all cold hardy choices. If you plant now, you will get some growth before the cold of winter sets in, then in the spring when the ground thaws you can till the crop under.

A couple of things to remember should you get more growth than you expect, such as wheat that grows a foot high or more, you may want to mow it down first. And finally, it’s important to remember that you want to allow at least two to three weeks between the time you till under and you transplant in or plant crops. This is because the process of decaying organic matter actually depletes nitrogen for a short period of time before it reverses and starts to provide nitrogen, so your plants would be competing for nitrogen during this period. As my grandpa used to say, “Dios nos dara el pan de cada dia, pero no en galletas”…..we have to work for our daily bread, but we should work smarter, not harder. Cover crops are actually a pretty easy way to manage soil health and I encourage farmers and gardeners to try them out.

Margaret Campos is active on her family’s farm, Algo Nativo Farm/Comida de Campos in Embudo, NM which produces vegetable crops including beans, chile, eggplant, various herbs, potatoes, asparagus, corn, tomatoes, onions, cabbage, chile, and broccoli. They also have fruit crops that include raspberries, blackberries, peaches, quince, nectarines and more.