New Evidence Shows Fertile Soil Gone From Midwestern Farms
Evan Thaler for NPR
Farming has destroyed a lot of the rich soil of America’s Midwestern prairie. A team of scientists just came up with a staggering new estimate for just how much has disappeared.
The most fertile topsoil is entirely gone from a third of all the land devoted to growing crops across the upper Midwest, the scientists say. Some of their colleagues, however, remain skeptical about the methods that produced this result.
The new study emerged from a simple observation, one that people flying over Midwestern farms can confirm for themselves. The color of bare soil varies, and that variation is related to soil quality.
The soil that’s darkest in color is widely known as topsoil. Soil scientists call this layer the “A-horizon.” It’s the “black, organic, rich soil that’s really good for growing crops,” says Evan Thaler, a Ph.D. student at the University of Massachusetts, Amherst.
It’s full of living microorganisms and decaying plant roots, also called organic carbon. When settlers first arrived in the Midwest, it was everywhere, created from centuries of accumulated prairie grass. Plowing, though, released much of the trapped carbon, and topsoil was also lost to wind and water erosion. The soil that remains is often much lighter in color.
Thaler and his colleagues compared that color, as seen from satellites, with direct measurements of soil quality that the U.S. Department of Agriculture has carried out, and found that light brown soil contained so little organic carbon, it really wasn’t A-horizon soil at all. The topsoil layer was gone. What’s more, Thaler found that this was consistently the case on particular parts of the landscape. “The A-horizon was almost always gone on hilltops,” he says.
Thaler believes that a century of plowing is to blame. The soil gradually fell down hillsides, a little bit each year, as farmers tilled the soil.
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Paul Overby believes in trial and error. Since 1993 he and his wife, Diane, have been running Lee Farms, the family farm spread over 1,400 acres (5.5 km sq) in North Dakota, near the US-Canada border. In that time they’ve changed course quite a few times: diversifying the grains they grow, starting to manage the soil according to individualised zones, limiting the tillage of the land, and experimenting with planting cover crops alongside their main commodity crops.
Together, these techniques have transformed their land. “The soil should crumble like a brownie would,” Overby explains. When he took over the farm from his parents, the soil had a lot of fine particles. The silt, sand, and clay making up the soil would come apart easily. After a heavy rain, the soil would become very sticky, as the fine texture didn’t allow much room for drainage.
Today, the soil is dark and full of large clumps, with bigger gaps between the particles. Water is now able to reach the deeper layers of the ground. “When you walk across my fields, it feels like you’re walking on a carpet,” Overby says.
For farmers like him it isn’t an option to ignore what lies beneath. Soil is critical for the food everyone eats. Healthy soils matter not just for producing 95% of global food supplies, but also for safeguarding other aspects of human health. Soils sequester a massive amount of carbon (over twice as much as the atmosphere and all plants combined). In addition, microbes in healthy soils lead to the development of antibiotics and other medicines.
So it’s alarming that this foundation of food production and health is in trouble.
Up to 40% of the world’s agricultural land is degraded, and it’s estimated that the economic losses amount to $40 billion (£30bn) per year. But almost all of the world’s arable land is already being farmed, so it’s not an option to leave existing plots and move on to new ones.
Intensive farming, climate change, deforestation, industrial activity and natural processes have all taken their toll on soil. The effects can be physical (such as erosion of fertile topsoil), chemical (such as acidification of soil), or biological (such as loss of microbes). Where soil remains, overworking it makes it weaker due to less nutrient absorption and drainage of water – for instance, when soil becomes compacted by overgrazing of livestock.
But fairly simple techniques can make a big difference. In Ghana, planting elephant grass helps to hold soil together. In Burkina Faso, the zai (half moon) method involves farmers digging large holes in soil and putting in compost when rains are arriving in order to conserve water and soil. In India, using trenches and small walls during the rainy season helps to preserve nutrient-rich topsoil and prevent soil erosion.
Indeed, around the world farmers and scientists are working to invigorate soil where possible. And they’re finding that sometimes the best solutions are the basic ones.
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“Nothing is nature is given, it’s won.”
https://www.youtube.com/watch?v=9lM39LI0l9w
Greg Judy at Green Pastures Farm: “Folks here is the film documentary that I mentioned last year that our friends at MarketPlace fiilmed on our grazing operation. Enjoy! Also their blog they wrote while filming the documentary : https://market-pl.com/the-regenerativ…“
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Grazing in Harmony – C Lazy J Livestock operation, Phillips County, north central Montana
Craig and Conni French always considered themselves good land stewards, but six years ago things really began to change. They came to realize their cattle ranch’s fate was tied to healthy soils and grasses.
“We are a part of this ecosystem,” Conni says. “How do we live in harmony and work together within this system?”
They found the answer in holistic ranch management techniques, which called into question long-held, traditional ways of thinking. Toward that end, the Frenches implemented rotational grazing on their C Lazy J Livestock operation in Phillips County in north central Montana.
The drastic changes that followed required a leap of faith for the fourth-generation ranchers. They traded harvesting hay for grazing methods that let their cattle harvest the forage themselves. Such changes didn’t happen overnight, and each came with its own risk and learning curve.
“To be a steward of the land in my mind is recognizing the importance of a natural resource, and it is to be harvested,” Craig said of the grass on the ranch. “That’s the whole point of renewable.”
The Frenches recognize that without a healthy, sustainable land base they will not be able to carry the ranch into the future. Increasing grass and soil health are considerations that are always front of their minds in their decision-making process.
With the use of electric fence, they have increased the number of cattle moves and the number of pastures. They now move cattle around 40 times per summer. This allows for increased rest for each pasture and more control over where and when cattle are grazing.
Last fall Craig and Conni were the recipients of the Montana Leopold Conservation Award®, given in honor of renowned conservationist Aldo Leopold. The prestigious award recognizes farmers, ranchers and forestland owners who inspire others with their dedication to land, water and wildlife habitat management on private, working land.
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