We’re all familiar with the endangered species that receive most of the publicity: giant pandas, tigers, Asian elephants, sea otters… The list goes on. But did you know that earthworms are also classified as an endangered species? And you might think: so what? Who cares about earthworms?
Despite the fact that this species is creepy-crawly and might not be the best face for the WWF, the reality is that earthworms are too important a species to lose. And here’s why.
Why Are Earthworms Important?
You may heard the buzz about pollinators in the news. #Savethebees is trending all over social media and gardeners around the country are working to keep bees and butterflies safe. Pollinators are incredibly diligent workers who keep the world fed, but did you know that the same is true of earthworms?
Earthworms are the intestines of our soil, and without them, our soil would be in serious danger–and so would our crops.
Earthworms will eat and shred residue within the top, middle, and bottom layers of soil. By doing so, they support microbial bacteria. They will also leave soil casts (that’s right; they produce soil) that are rich in nutrients, such as nitrogen, phosphorous, potassium, and calcium. If you’re a learned gardener, then you know that these are the biggest nutrients responsible for plant growth.
In addition to improving the soil’s nutrient level, they also improve the soil’s structure in two ways:
- By burrowing, earthworms aerate the soil, which helps soil hold and drain water more efficiently. This, in turn, reduces erosion and flooding.
- Earthworms create channels in the soil lined with the nutrients they cast. Plants’ roots will follow these channels, improving root growth.
Farmers know that earthworms naturally improve soil and plant health, but in recent years, their numbers have declined. And farmers are responsible.
How does Agriculture Affect Earthworms?
There are various factors that affect earthworms:
- Amount of Organic Matter
- Soil pH, type, and depth
- Moisture-holding Capacity
Due to these factors, earthworms are not present in all gardens or crop fields. They need soil with lots of organic matter on which to feed and a pH of at least five. They also need moist, medium textured soil that is deep enough for them to burrow. So sometimes the presence of earthworms depends on the part of the country in which one is located.
Yet, conventional agricultural practices have exacerbated soil conditions, making it nearly impossible for earthworms to thrive in soil that used to be healthy enough for them.
According to researchers, one of the biggest agricultural practices that has negatively impacted earthworm populations is tillage.
Tillage, which entails digging, stirring, and overturning soil in order to prepare it for new crops, disrupts the earthworms’ habitat. This practice not only destroys the burrows that these worms have made for plants’ roots and for soil aeration, but it also destroys worm cocoons and worm bodies. In a 1995 experiment, researchers found up to 30 times more earthworms in no-till systems compared to plowed fields.
Yet, not all earthworms react the same way to tillage.
Types of Earthworms
There are three types of earthworm: epigeic, endogeic, and anecic.
Epigeic earthworms live in the uppermost layer of the soil: surface litter. These earthworms move horizontally and hardly perform any burrowing. These worms contribute little, if any, to agriculture.
Endogeic earthworms live in mineral topsoil layers. They consume large quantities of soil and create three-dimensional mazes of burrows.
Anecic earthworms live in permanent, vertical burrows in the depths of soil. Their burrows extend several feet downward, and the worms use these burrows to transport surface residues into deeper soil layers. This helps to increase soil fertility and prevent disease.
Endogeic and anecic earthworms contribute the most to agriculture. Endogeic earthworms can tolerate tillage because their burrows are not permanent, and they require nutrients from soil rather than litter. Anecic earthworms, however, cannot tolerate tillage. Their burrows are permanent and take a large amount of energy to make. When anecic earthworms’ burrows are destroyed, they might not have the energy to reform them. In addition, these worms require nutrients from litter. When soil is tilled, the surface litter is destroyed, leaving little for these worms to consume.
Yet, tillage isn’t the only agricultural practice that affects earthworm populations.
Other Ways Agriculture Affects Earthworms
How else does agriculture affect earthworms?
Other agricultural practices can affect earthworms in both negative and positive ways. For instance, the use of both organic and synthetic fertilizer can provide soil with essential nutrients, thus providing earthworms with better nutritional content. There are some fertilizers, however, that can negatively affect earthworms.
Researchers have found that ammonia and ammonia-based fertilizers decrease earthworm populations due to salt content and the fertilizers’ affect on soil pH. In fact, direct exposure to ammonia can kill up to 10 percent of an earthworm population.
Not only are some fertilizers toxic to earthworms, but so are some insecticides. Researchers have found that carbamate insecticides and some organophosphate insecticides are highly toxic to earthworms.
So how can farmers (and gardeners) help revive earthworm populations? Well, many farmers have already begun adopting new farming practices, some of which can support earthworms. These practices belong to a new agricultural movement: regenerative agriculture.
Regenerative Agriculture can Help Earthworms
Regenerative agriculture refers to farming practices that reverse climate change, support soil fertility and health, limit water waste and pollution, and increase biodiversity. A large part of this practice includes rebuilding soil organic matter, which has been mostly depleted through traditional farming practices. Regenerative farmers participate in one or more of the following four practices:
- Minimum or no Tillage
- Building Biological Ecosystem Diversity
- Well-managed Grazing Practices
- Increasing Soil Fertility
Minimum or no tillage practices support soil health and reduce erosion, but they also save earthworms. While extensive tillage negatively affects earthworms, minimum tillage methods leave surface residue throughout the year for earthworms to use for food, insulation, and protection.
To support and increase diversity within the ecosystem, regenerative farmers restore the soil’s microbial community population and structure, which is accomplished by using compost to add nutrients to the soil. This, in turn, feeds earthworms. Regenerative farmers also use cover crops and crop rotations to support ecosystem diversity, and this is another way that farmers can help earthworms.
Cover crops like alfalfa and clover provide earthworms with high protein content and reduce the need for tillage, giving earthworms more time to eat and reproduce without disturbance. Crop rotations using hay, grass, and legumes also support and increase earthworm populations.
Regenerative farmers focus a lot of their energy on increasing soil fertility. By employing minimum tillage practices, cover crops, crop rotations, and composting, these farmers increase soil fertility. Of course, soil infertility isn’t simply caused by over-tillage. The excessive use of fertilizer plays a large role in soil infertility.
Fertilizer’s Role in Soil Infertility
While fertilizer provides soil and plants with essential nutrients, excessive fertilization can actually damage soil, which affects earthworms.
Fertilizers that contain salt and chemicals can affect the microbial community, alter the soil’s pH, and increase the rate at which soil releases carbon. This in itself is bad enough. But even when farmers use organic or natural fertilizers, they can still negatively impact soil health. This is because farmers will often use too much fertilizer. When crop yields drop and plant health suffers, farmers will often introduce more fertilizer with the belief that this will solve the problem.
But introducing more fertilizer is not the solution. Plants are extremely efficient. They know exactly how much they need to consume in order to thrive, and they will never consume more than is necessary. So adding more fertilizer won’t increase crop yields and plant health; the fertilizer will sit in the field, washing into rivers and streams via runoff.
One way farmers can increase soil fertility and help earthworms is by using xVital, an all natural liquid fertilizer. xVital is made of nitrate and ionized water, so it contains no salt or chemicals. And unlike conventional nitrogen-based fertilizers, our fertilizer contains no ammonia, so it won’t harm earthworms.
In addition to switching to xVital, farmers can also switch from toxic pesticides to non-toxic pesticides (or they can find alternatives to pesticides, such as the introduction of predators). In doing so, farmers can rebuild the earthworm population, increasing soil fertility and food production.
Now you know how agriculture affects earthworms. Let’s not add another name to the extinct species list. We can save earthworms by adopting smarter, cleaner agricultural practices.