By Kayla Humphries
Let’s say that you have just started a fruit and vegetable garden in your backyard. You’ve sown your seeds and done most of the preparation. But, there’s one problem- you’ve left massive patches between your plants bare! Think about it- what happens to patches of bare soil? Weeds will invade the area. So, you till your soil. This is your second mistake. Tilling disrupts the micro-organisms that contribute to nutrient production and flow in the soil. What do you do now? Well, according to a sustainable agriculture review by Scholberg et. al (2010), you should be planting cover crops.
Since the Neolithic Era, better known as the “New Stone Age”, humans have been utilizing cover crops in agriculture to restore soil fertility and, hence, enhance crop production. Different cover crops have been used by farmers all over the world. One of the benefits that push people towards them, other than soil health, is that cover crops may also serve as forage crops for livestock and people. Similarly, these crops will surely provide food and habitat for pollinators, greatly increasing plant viability. This was the case for farmers in Southwest Asia, who used peas (Pisum sativum) and lentils (Lens culinaris). Another example is in 1870s Florida and 1920s Guatemala, where velvet bean (Mucuna pruriens) was introduced to citrus farmers as forage crops and for rotation with maize-based systems. In the 1960s, vetch (Vicia sativa) and oats (Avena sativa) were introduced to Uruguay as “green manure”- it is produced to be incorporated into the soil while it’s still green. This adds organic matter to the soil for the micro-organisms. Warmth and moisture contribute, similar to creating compost.
It may seem that cover crops are something exclusively for farms, but learning about cover crops is also incredibly helpful for college students for two reasons. Reason One: Students can use cover crops in their gardens at home (or in their raised beds, for those who lack yard space). They do not require any extra land, they are meant to be sown in between what you already have planted. As a student myself, I am broke enough to know the merits of a well-kept garden. Reason Two: Even if you don’t have a garden of your own, campus gardens are popping up all over the country! The College of Charleston has a few sustainable gardens of its very own. By becoming involved in your campus garden and helping to incorporate cover crops, you are benefitting from yields being increased organically. Similarly, any extra produce can be donated to local non-profit organizations such as Stone Soup Collective, which is a great way for students to become involved in activism and give back to their community.
Another reason that you may be interested in using cover crops is that you’ve heard that it is a mechanism used in sustainable agriculture. This is true because cover crops establish and maintain good soil organic matter (SOM). According to the review, cover crops cycle SOM into the soil at a faster rate than SOM breaks down. This heavily favors root growth, leading to improved soil aggregation and soil structure, enhanced water infiltration, retention, drainage, and soil aeration- Therefore, soil erosion and runoff are reduced. Further, cover crops are a natural and inexpensive climate change solution because of their ability to capture atmospheric carbon dioxide (CO2) into soils.
If you’re wondering how to choose your cover crops, know that people use different types of cover crops depending on their garden’s individual needs and the biome in which they live. There is no such thing as the “perfect” cover crop! You can, however, find a combination of cover crops that work for you. For example, let’s say that these are my criteria: I live in a cool, dry climate and want to restore nitrogen to the soil while also getting utilitarian value (I want to eat them!) from my cover crops. In that case, I might choose legumes such as lentils or peas. Some suggestions specific to the Lowcountry: mustard, radishes, oats (plant with legumes as companion plants!), and barley are all great options that are suited to South Carolina’s spring weather. However, there are several other great ones, so don’t limit yourself to this list.
The last thing that you must know is that in practice, discovering what cover crops fulfill your garden’s individual needs is a trial-and-error process. In other words, be prepared for this to be a learning experience! It is okay, even expected for there to be screw-ups. That is part of the challenge and the satisfaction of working with nature. If you are interested in incorporating cover crops into your garden, the link to Scholberg et. al’s review, “Cover Crops for Sustainable Agrosystems in the Americas”, can be found here. Happy gardening!
Scholberg, Johannes M., et al. “Cover Crops for Sustainable Agrosystems in the Americas.” Genetic Engineering, Biofertilisation, Soil Quality, and Organic Farming, 23 Mar. 2010, pp. 23–58., https://doi.org/10.1007/978-90-481-8741-6_2.