The 4 Principles for Healthy Soil: #1 Keeping the Soil CoveredOn October 23, 2021 by Vlad9 min read
Keeping the soil cover is the first step when following the four principles of conservation agriculture. Why is this important? First, the labor is much less intensive, and it helps to reduce gas emissions while protecting the topsoil from eroding away. It also promotes the protection of arable land and plant diversification. This article will explain why you should keep the soil cover as much as you possibly can, as well as how to do it efficiently.
Conservation agriculture has been around for more than you might think. Farmers have been doing this for thousands of years, all over the world. Depending on the area that we look at, the soil was covered with diverse types of mulches: leaves, grass or hay where it was readily available, rotting wood scraps in the northern climates. Pre-columbian farmers used rocks for mulching their fields with great success and they were not the only ones.
Why should soil be covered?
The reason why it’s essential to keep the soil covered is that it helps retain water around your plants. Water is vital for the growth and development of all species on earth, and the longer you can keep the soil at optimal humidity, the healthier your plants will be.
Not just that, but uncovered soil is exposed to weather erosion and scorching sun, which automatically hurts the vital parts of your soil health. You might not always see it with the naked eye, but every time it rains, every time the wind gusts over empty topsoil, it takes some of it away as dust. Over time, this strips away the top layer of soil and organic matter.
According to a survey conducted by the Natural Resources Conservation Service, soil compaction from wind and heavy rainfall is a global issue. In the past 70 years, it was found that around ⅓ of the world’s arable land has been damaged or completely lost. This has led to an increased level of carbon monoxide, and loss of carbon in the soil.
How do you choose the right mulch?
To help with this worldwide issue, you will need to learn what are the right types of mulches for the soil you’re working with, as different types of climates need distinct types of mulches for an optimal soil lifespan. Start by making a list of mulch materials that you can source locally and cheaply. Then figure out the properties of that mulch and consider how it will affect your garden.
For example, in a colder climate, you will benefit from a darker-colored mulch that will absorb sunlight and warm the soil underneath, while in warmer climates you will need light-colored mulches to avoid absorbing heat into the ground. If you somehow use compost as mulch when you are not supposed to do so, you risk getting the temperature of the soil too high, which could lead to problems with germination due to the fact the compost will be way too hot for the plants to thrive.
Also, some types of mulches, most often hay-based ones, can have traces of herbicides and weed seeds which will kill your plants. Some mulches might carry unwelcomed visitors with them, from diseases to weed seeds or pests. Depending on the pest situation in your garden, choose a type of mulch you know won’t attract these, as slugs and pill bugs may be attracted to some types of mulches, and will unavoidably move to your plants next.
There are a few other benefits when it comes to covering the soil with mulch. One of these is the proven fact that mulches will help preserve and add more organic matter into the soil. When they decompose, the right type of mulches will provide nutrients for the growing plants, so it’s one of the best things you can help your garden (and the environment) with.
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How to use mulch in your garden
Mulching with straw or hay
One of the most popular types of mulches is straw. It’s excellent because it’s made up almost entirely of carbon. As we said before, you’ll need to check your straw carefully for weed seeds and make sure you’re getting it from a reputable supplier, so you avoid getting straw that is traced with herbicides. Because this is a light-colored mulch, use straw (or hay) if you want to keep the soil at a cooler temperature. If you chose hay, which decomposes quite rapidly, you’ll need to keep layering it every six months following the Ruth Stout principles.
Mulching with compost
Compost is another popular mulch all over the world, thanks to Charles Dowding the guru of no-dig gardening. Normally, compost has a dark color, and it’s used to warm the soil significantly. It’s not a desirable choice for the summertime, as the elevated temperatures can pose an issue, especially in the warm climates where summers are already quite hot. What you can do, if you still want to use compost, is to layer a light-colored mulch on top of it, or simply apply it very early in the spring.
Mulching with leaves
Other useful mulches are leaves and leaf mold. They are very nutritious for the soil, so much that some gardeners call them gold. Grass clippings are also full of nutrients, especially the ones from early spring. The only problem with that is you must make sure you’re getting them from a place that has not been sprayed. Fresh grass clipping must be applied in thin layers over time, otherwise, you run the risk to start a miniature anaerobic compost pile that will burn your plants.
Mulching with wood chips
Mulching with woodchips is the core idea behind the Back to Eden style of gardening. I’ve seen dozens of successful gardens that have been fully mulched with woodchips and they all look amazing. From what I can tell both hardwood and conifer woodchips work just as well, contrary to what some internet articles claim.
Bark mulch can be used if it was not previously dyed, but it also has to be used in combination with compost. Avoid using sawdust as it can cause problems with rot and fungus around the plants and it stops water and airflow more than it stops weeds from growing through it.
Mulching with cardboard
Paper and cardboard are great as well, but generally, they’re used in combination with other mulches, like compost or woodchips, because they are too light to remain on the ground, and high winds can blow them away. Since paper products are not getting recycled enough, this is one sure way to help the environment benefit from it, but make sure it has no chemicals in its composition, no dye or wax and remove all plastic tape before using them.
Mulching with landscape fabric
Plastic mulches such as landscape fabric and polyethylene can be used safely, even though research shows microplastic is not the best thing for the soil. However, when you must use them, they are useful to warm the soil up and to block the growth of new weeds. Plastic mulches, especially silage tarps, also help preserve moisture during dry seasons.
Cover crops as mulch
Cover crops are an often overlooked alternative to traditional mulch techniques, but they can outperform them. Seeding Winter Rye or Sorghum Sudangrass in the fall will help keep the soil in place over winter. The plant growth resulting will keep the soil sheltered from the wind and direct sunlight, while the root system keeps the soil in place, add carbon to the solid and offer a safe haven for the soil microbiology throughout the winter months.
In early spring those crops are cut down and left in place. This will act as a mulch for your annual crops and it will also decompose through the season, further improving the quality and health of your soil.
Mulching with rocks
Despite rocks and other hard materials being used in the past as mulch, nowadays, they’re not quite recommended because they’re heavy, they tend to compact the soil, and they do not allow it to breathe. Modern times came with much better mulch alternatives, such as the ones we mentioned above, which are easier to handle and clean up if you want to change them. Lithic materials can be used still, but your life will be much harder.
One use I did find for mulching with rocks is to protect young tree saplings and keep the grass from overwhelming them.
A bit more about cover crops
Since these are some of the best types of mulch you can use, we’ll look a bit more at these. They bring multiple benefits to the soil, so depending on what your goals are with them, and if you have the space, you can always plant a couple of them. There are several winter and summer cover crops that can be successfully used as mulches. Sorghum Sudangrass is a winter mulch, which can be planted in the fall. Peas and oaths are great as well. After the above-ground mass freezes and breaks down, it turns into an excellent mulch for the spring.
Most of these mulches are also great to fix nitrogen in the soil and create organic matter and regulate oxygen intake and outtake. Before being “killed” to be turned into mulch, they use photosynthesis to create glucose and give the soil a boost of nutrition. Rye, aside from being a great mulch, keeps weeds away with chemicals that prevent weeds from germinating.
How to apply mulches
It all depends on your preference and practices, so there are no set rules in place for the way you apply mulches. The context in which you must apply them will make all the difference in how you do it and how much you need. Avoid applying more than you need, however, because your seeds may not germinate, as the mulch won’t hold the moisture as it should. A layer should be 2 to 4 inches around the plant, leaving enough space to avoid rot at the base, and allow the plant to get enough oxygen. Try to apply the layer evenly and smooth it out with your hand or with a rake.
Even though mulching is considered to be an early spring practice, it can be applied at any time for various reasons, especially to replace an older mulch that started to decompose. To put in perspective, our hay-mulched garden beds need a fresh layer of hay added every month or so.
The best way to use your mulch is to do in-depth research of the ones you have available or the ones you plan to use. And remember that healthy soil is always less prone to disease, is more resilient to pests and it’s a much better legacy to leave behind for our kids.
Continue reading about the 4 principles of healthy soil in the next article: Keeping the soil planted!
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We (Vlad & Greti) are building a home on a homestead in a rural area of Romania in Western Europe and sharing our story as two passionate gardeners who ditched the city for a simpler, better life.