Imagine it’s a cold winter morning. The sun hasn’t been seen for a week and the clouds are heavy and gray. You wake up in your warm bed, deep in the covers and the last thing you want to do is get up and face the elements. You know how much you love that cover? So does your soil.
One of the easiest things we can do to promote soil health is to simply keep it covered. That’s it. Cover your soil.
Ever hear of the dust bowl? It was a catastrophe. Years of intensive agriculture and leaving the soil bare had destroyed soil structure and moisture retention. When droughts happened, and wind picked up, goodbye soil. There was nothing to anchor the soil, nothing to protect the soil, nothing to cover the soil.
The dust bowl was so bad that the U.S. government responded by creating an agency focused directly on soil health! That agency is now the NRCS and they are a wonderful source for growers interested in soil health.
Soil cover: what it’s all about
Keeping your soil covered will help you to manage soil moisture and temperature, suppress the germination and growth of weeds, shield the soil surface from washing away, and can add organic matter over time.
Soil cover helps to manage moisture and temperature by providing a barrier to trap water and physical cover that insulates and holds heat. Soil cover can be anything from cardboard and newspaper to living cover crops to synthetic material such as tarps or weed suppression fabrics. There is no “right choice” in terms of cover, it all depends on what fits in best with your system and budget. There are pros and cons to different cover types though, and we will briefly list some below.
Cover types – cheap options
Cardboard and paper are good budget choices but need to be applied in a thick enough layer to not lose effectiveness part way through the season. Also, because they are light, they need to be weighed down by the application of additional ground cover such as mulch or mulching compost. It is important to note that it is 100% okay for you to combine different types of cover. The important part is we have our soil covered.
Other cheap options for cover material include grass clippings, trimmings from trees and bushes, and dead leaves. A benefit to using these materials is that as they breakdown they will cycle nutrients and organic matter into the soil. The bad news is, as carbon-rich material they will tie up nitrogen where they are in contact with soil, making it temporarily unavailable. This is an important consideration as it may change the application timing or planting date or require some nutrient amendments in the short term. Timing mulch applications with crop growth stage may be another strategy to reduce the effects of the temporary nutrient unavailability.
Cover types – more expensive but still economical options
By now it should be no surprise that we are fans of cover cropping here at The Potanist. This is our preferred method for covering our soil because it also accomplishes another tenet of soil health, keeping it planted.
Depending on what you are trying to accomplish with your ground cover and cover crop, there are many different options available.
High carbon-to-nitrogen ratio (C:N) plants breakdown slowly and provide thicker cover for longer periods of time. Low C:N plants breakdown faster and provide less cover over time but help to cycle nutrients (specifically nitrogen) back into the soil.
High C:N cover crops tend to be grass or grain crops, examples include rye grass, sorghum-sudan grass, oat, and wheat. Low C:N plants such as hairy vetch, clover, or alfalfa should be terminated before seed set to maximize the amount of nitrogen in non-reproductive tissue. The cover can then be amended with wood chips, sawdust, or other high C:N residue options to prolong the cover.
For spring plantings, finding a winter-tolerant cover crop allows you to start the season with fresh cut or crimped ground cover that can offer an early season nitrogen boost and weed suppression.
Downsides to cover crops as soil cover can include an increase in cost for purchasing the seed, associated fertility costs of growing a crop, and the effectiveness of cover crops generally relies on good germination and biomass production. That is, a bad growing season can render a cover crop useless.
Cover types – more expensive options
Weed suppression fabrics or plastics can be used but are expensive and tend to breakdown and leave problematic residue in fields. Weed suppression plastics especially, should be avoided if possible. As a grower you are restricted by what you can afford and locate, so plastic cover is better than no cover, but that’s about it. Weed suppression fabrics are easier to manage than plastics and can be used effectively in hoop house or greenhouse systems.
Weed suppression plastics are often used when growing Cannabis in raised beds with drip tape but are a pain to clean at the end of the season. Incorporating mulch layers or using deep compost beds could be an option in place of plastics.
Tarps are an excellent option for temporary ground cover but be sure your tarps are UV-resistant. Leaving tarps on beds for multiple weeks in the summer and months in the winter can go a long way in reducing weed seedbanks. Tarps must be secured to the ground, and you should closely mow the area you are going to tarp before doing so. When ready to plant you can remove the tarp, prepare your beds, and be ready to start the year weed free.
Conclusion
Soil cover provides many health benefits and acts as soil armor. In order to build and maintain soil health you need to protect the integrity of the soil. Cover, both organic and inorganic, can help to protect soil structure and permeability and help stop the runoff of fertile topsoil. Its easy to do, it can be affordable, and it will only help. Cover your soil today.
