Iowa has lost half of its soil richness

Iowa has lost half of its soil richness
Published: Sep. 27, 2023 at 10:22 PM CDT
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AMES, Iowa (KCRG) - “Black Gold” - Iowa’s rich, nutrient-dense topsoil has provided for generations of farmers, but it’s slowly losing its nutrients. Researchers at Iowa State University say Iowa has lost half of its soil richness, due in part to farming practices.

Bradley Miller, an agronomist at Iowa State University, says the soil has changed since settlers came and converted the prairie into farmland.

“Since that time, we have been draining the soil as well as tilling it. And so now that, so it’s a little more dry, a little more exposed to oxygen to that tillage practice, that is actually burning off some of that organic matter,” Miller said.

That tilling is one of the main reasons for the loss of nutrients.

“If the soil is intact, it’s a little bit protected from the air. And when you till it, you are flipping it over exposing it more to the air and the more exposed to the air, the oxygen in the air actually allows for that organic matter to decompose more and be released into the air,” Miller said.

This summer’s drought is expected to impact crop yields, but Miller says it’s not the same with soil health.

“This summer we had less rainfall, but overall we’ve been seen an increase in the intensity of rainfall events. And so that sets us up for more erosion,” Miller said.

Marshall McDaniel, also an agronomist at Iowa State, says there are a few ways farmers can help preserve the soil - like not tilling and growing cover crops.

“Not only do cover crops prevent erosion, but they take up nutrients that can leach and cause water quality issues that are also a big major issue in Iowa, as well and those cover crops are preventing erosion, but also adding more organic matter,” McDaniel said.

McDaniel says adoption has been slow, but is starting to pick up.

“Because of the carbon markets, and private companies wanting to pay farmers to do some of these soil health-promoting practices, there’s an increased attention in both of those practices,” McDaniel said.

McDaniel says cost and time are the biggest barriers for farmers.