Soil professors awarded $498,000 to study phosphate interactions in agroecosystems

Research led by two University of Maine professors aims to provide a greater understanding of the mechanisms by which soils adsorb phosphate and maintain it in plant-available forms to increase the sustainability of agriculture in the United States.

Tsutomu Ohno, a professor of soil chemistry, and M. Susan Erich, a professor of plant and soil chemistry, were awarded a $498,000 grant from the United States Department of Agriculture’s National Institute of Food and Agriculture for the project, “Biogeochemistry of Phosphate and Carbon Interactions in Agroecosystems: Coupling Experimental Data with Density Functional Theory.”

The goal of the three-year study is to provide the foundational knowledge to design management practices that significantly increase phosphorus use efficiency in agroecosystems and to understand soil carbon stabilization.

An agroecosystem can be described as a farming system, which includes basically everything — organisms and their environment — involved in the agricultural production of food, according to the researchers.

“There is an increasingly urgent need to develop science-based agricultural practices that significantly increase phosphorus use efficiency compared to current practices,” Ohno says. “This would allow a reduction in synthetic fertilizer inputs, which reduces adverse impacts to off-farm surface and groundwater resources.”

The researchers hope to learn how water-soluble soil organic matter alters phosphorus adsorption to soil mineral surfaces. Ohno says the research team thinks the presence of such organic matter will increase the solubility and bioavailability of phosphorus by affecting mineral bonding.

“Fertilizer use and other technologies have increased food production in the U.S. which has increased food security for many, but has come at the cost of adverse environmental impacts and decreasing sustainability of U.S. agriculture,” Ohno says. “Agricultural practices with excessive phosphorus loadings have greatly impacted the Chesapeake Bay and the Gulf of Mexico aquatic systems leading to dead zones caused by excessive nitrogen and phosphorus runoff from agricultural fields.”

The study will focus on chemical and biological processes that are the foundation for a sustainable agroecosystem, providing molecular-scale chemical data to inform landscape-scale ecological models necessary for decision-making in a changing global environment, according to the researchers.

The UMaine researchers are working in collaboration with environmental chemist Patrick Hatcher of Old Dominion University and geochemist James Kubicki of University of Texas at El Paso.

Contact: Elyse Catalina, 581.3747