World Soil Day 2023: Celebrate It While It’s Still Here..
By: Katie Koblasz and Margaret Brogan
World Soil Day is observed annually on December 5 to celebrate the multifaceted role soil plays in our everyday lives. World Soil Day serves to remind us that we walk over soils in more ways than one.
The state of soil is in critical condition globally. According to research conducted by the University of Massachusetts Amherst, over the past 160 years the Midwestern United States has lost 57.6 billion tons of topsoil due to overconsumption, unsustainable human activities, farming practices, and erosion.
Soil is classified as a finite resource, because its loss and degradation is not recoverable within a human lifespan. According to the Food and Agriculture Organization of the United Nations (FAO), it can take up to a thousand years to produce just two-to-three centimeters of soil.
One of the main contributing factors to this soil loss is soil erosion, a process by which topsoil is removed from landscape through wind, water, and tillage. Soil erosion occurs at a much higher rate than the soil formation rates.
The rate of soil erosion occurs at a rate 25 times higher than the rate at which topsoil forms, even when U.S. The Department of Agriculture's guidelines are followed, according to research conducted by the University of Massachusetts Amherst.
Although soil erosion can occur as a result of natural processes, the rate of erosion is significantly increased and accelerated by unsustainable human activities, according to the FAO.
The removal of vegetation from landscape is a major contributor to soil loss and erosion.
When the landscape is stripped of vegetation the soil becomes susceptible to erosion and run-off, because the bare topsoil is left exposed. However, when vegetation covers soil it prevents soil loss, because the roots help hold the soil in place and reduce the amount of erosion and run-off, said James Reichard, a professor of geology at Georgia Southern University.
Over 95% of the food humans consume comes directly or indirectly from our soils. Soil supplies more than half of nutrients essential to plants survival, according to the FAO. Therefore, a large fraction of life on earth is dependent upon healthy, quality soils.
Soil loss can inhibit the ability to have productive agriculture, because quality of soil decreases as topsoil decreases. When topsoil are gone what is left is just plain dirt that isn't very fertile which hinders crop production, said Reichard. Therefore, higher levels of top-soil presence yields higher-quality productive soil, which yields more productive crops, and vice versa.
Soil loss and erosion pose a significant threat to global food production and security because the ability to produce food is hindered. In some places, crop production and farming are unable to exist, because severe topsoil loss occurred, said Reichard.
“North Georgia used to have a lot of cotton and agriculture production, but now most of the soil in North Georgia has been washed away,” said Reichard. “As a result, they pretty much do not do agriculture farming up north anymore. That's one of the biggest consequences of soil loss, you can lose your ability to run agriculture.”
The removal of vegetation from the landscape leaves topsoils exposed, resulting in less infiltration and more run-off experienced.
“The balance between infiltration and runoff is disrupted,” said Reichard. “If you have grass and trees on the landscape and it rains, more water can infiltrate into the soil which recharges groundwater aquifers.”
The vegetation contains roots that extend down into the soil, and create cracks and fissures, which allows for more rapid infiltration and increased capacity for water in groundwater aquifers. Groundwater is used for drinking water by nearly 50 percent of people in the United States, according to Wildlife.org. However, the largest use of groundwater supply is for crop irrigation and agricultural production.
“Oftentimes, lost soil runs-off into streams, plugs the streams up, and causes flooding,” said Reichard. “This is called soil pollution. When the channels of the stream fill up with sediment there's less room for water, and an increased chance of flooding. Therefore, in places where we have severe topsoil loss, we have also increased flooding.”
Although the potential consequences of soil degradation paints a worrisome image for the future of agriculture, Peyton Sapp, the University of Georgia County Extension Coordinator for Burke County, says there is no cause for alarm.
“Farming practices of just growing a monoculture of cotton for extended periods and not doing some of the management practices that we do today, you could’ve easily made that comment,” said Peyton. “I would say that from somewhere around the late 70s until now, there’s been tremendous progress made in general farming practice.”
Burton Heatwole, a Burke County farm owner, said regenerative agriculture is the way forward. Regenerative agriculture focuses on the health of farmland and seeks to encourage sustainability in farming.
“It’s the way that daddy did it, grandaddy did it, it’s the way we’ve always done it, so we don’t really rethink it,” Burton said. “People say ‘We’ve always done it this way, why different?’ but the problem is it’s very broken and they just haven’t realized it yet.”
Tillage, the process of preparing soil for planting, plays a large role in maintaining soil health, and decreasing soil loss. No-till farming is one of the biggest methods to combat soil loss, because it keeps the soil in place.
“The first key thing is to limit the disturbance, meaning reduced tillage,” said Heatwole. “Every time you till soil you open it up for erosion, you lose organic matter, you lose moisture, you destroy structure, you germinate weed seeds, so it’s this big, massive list of cascading effects that come with tillage.”
Different crops require different types of tillage, said Sapp. Peanuts require deep tillage and more disturbance in the process of planting and harvesting. However, a tool known as a stripped till rig can be used for other crops to disturb the soil only in areas that are necessary for plantation, in turn the organic matter that holds soil in place is preserved.
After harvesting cash crops, planting cover crops, crops grown for the purpose of protecting and enriching the soil, is essential to maintaining soil health.
“You’ve got half of the year that nothing is growing in your field, that is very detrimental to soil quality because microbes are what holds soil together,” said Heatwole. “If there is no plant growing, there’s no photosynthesis happening, there are no sugars being made in the plant to be pumped down through the roots and into the soil to feed the microbes, they are starving.”
Cover crops serve a myriad of purposes for crop development. In addition to supplying nutrients to the microbiome, certain cover crops can be used as a food source for cattle grazing, which provides another layer of nutrients in the form of fertilizer. Cover crops may also assist in water retention.
“If a grower understands that a cover crop is going to be using a lot of moisture at X time, and he needs to plant his cash crop, he needs to terminate the cover crop and plant the cash crop in that optimum window before your soil moisture goes away,” said Sapp.
Soil itself is a diverse, living ecosystem. Maintaining the health of the soil requires keeping disturbances to a minimum, a consistent source of nutrients, and minimal exposure to chemicals which may create imbalances in the ecosystem.
“Anything that affects the biological life of the ecosystem, which is the soil, causes it to lose quality over time because it is a living, breathing organism,” said Heatwole.
Soil hosts a diverse array of microorganisms, both beneficial and harmful to crop development. Nematodes, microscopic worm-like organisms, play an important role in soil health.
Plant-parasitic nematodes feed on cash crops and create problems for farmers, while others feed on fungi and bacteria, which produce nitrogen that benefits the soil. Predatory nematodes help control the population of other nematodes, including those that are plant-parasitic.
“The root-knot nematode can feed on cotton and corn,” said Sapp. “That means he’s a bad guy for us, but some of the other free-living nematodes, the good guys, eat them.”
Although sometimes necessary, the introduction of pesticides can disrupt the balance of the soil ecosystem. The same pesticides that kill off harmful organisms also kill off those beneficial to the health of the soil.
“It’s important to minimize things like fungicides, herbicides, and pesticides because everything has unintended consequences,” said Heatwole.
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