Spring 2009

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Capturing Carbon - Sustaining Soils

Soil scientist Mahdi Al-Kaisi researches how soil management, tillage practices and cropping systems can improve and increase organic matter.

Carbon buried in the soils of the Midwest has made the 25 million acre region the site of the richest soil in the world.

“To have good productive soil you need good organic matter, which is synonymous with carbon and that’s what we have in the Midwest,” says Mahdi Al-Kaisi, associate professor of soil and environmental management.

Since the sod was first broken over 150 years ago, the soil in the Midwest has lost more than 50 percent of its organic matter according to Al-Kaisi.

“Every time you disturb the soil and change the soil temperature it starts oxidizing the organic matter. The microbes go into a frenzy when the soil is tilled and that’s how organic matter is lost,” Al-Kaisi says.

Plants pull carbon out of the atmosphere and return it to the soil to increase organic material. Al-Kaisi is researching how soil management, tillage practices and cropping systems can improve and increase organic matter.

“The Midwest’s soil is conducive to carbon sequestration or carbon storage, if we can manage the land well. There are several ways to increase carbon storage, such as putting marginal land in the Conservation Reserve Program, where it won’t be touched for an extended period of time,” Al-Kaisi says.

Lisa Schulte Moore works with researchers across disciplines to measure the amount of biomass produced and the amount of carbon remaining after harvest in various cropping systems.

To provide baseline data on how much carbon is retained using different crops, Lisa Schulte Moore, assistant professor of natural resource ecology and management, is working with agronomists, soil scientists, hydrologists and economists through the Landscape Biomass Project. Using different cropping systems the researchers will measure the amount of biomass produced and the amount of carbon remaining after harvest.

“As a landscape ecologist, I work at the macro scale. I’m really interested in how whole landscapes perform in terms of agricultural productivity, carbon storage and other benefits,” Schulte Moore says.

The researchers are experimenting with biomass cropping systems using several landscapes, from floodplain to hills, and comparing them to conventional cropping systems. The purpose is to find a system that is productive, profitable and environmentally sustainable.

“We’re hoping we can grow more biomass and subtract carbon from the atmospheric carbon pool,” Schulte Moore says. “If it works, producers implementing these systems could sell the carbon captured to two markets – the energy market and the carbon market.”

As researchers begin to understand how to measure carbon as a commodity, results show storing carbon in Iowa’s soils may not only provide future markets for farmers, but will improve soil and water quality as well.