Category: Plant and Soil Sciences
Deb Jaisi’s phosphorus research earns national award from the Soil Science Society of America
January 31, 2025 Written by Dante LaPenta | Photo by Katie Young
University of Delaware faculty member Deb Jaisi has received the 2024 Jackson Soil Chemistry and Mineralogy Award from the Soil Science Society of America (SSSA). This distinction honors advanced soil chemistry and minerals research.
“Because you would not consider me as a classical soil scientist, I’m honored that the organization values my contributions at the frontier of soil chemistry,” said Jaisi, a professor of environmental biogeochemistry in the Department of Plant and Soil Sciences.
To see his research in action, head to UD’s Harker Interdisciplinary Science and Engineering Laboratory. In the Environmental Biogeochemistry Lab, Jaisi investigates phosphorus, a critical element for plant fertilizers and a notoriously scarce nutrient.
Jaisi points out that phosphorus is not only important because of its environmental impact, but its value makes it an element critical for national security.
“Phosphorus is an important element in food and national security and in public policy to manage fertilizers and improve contaminated water bodies as it is in our everyday lives,” Jaisi said.
Humans extract phosphorus from non-renewable, natural resources around the world, but primarily in Morocco, home to 70 percent of the world’s total phosphate reserves.
When agricultural producers apply the right amount of phosphorus, it can lead to profitable crop production—the foundation of the Green (Agricultural) Revolution. But overuse can lead to loss from soils and adversely impact ecosystems.
“In agriculture, where we apply phosphorus, an essential nutrient for crops, we unintentionally create an overabundance of the nutrient in unintended areas—out of the agricultural soils,” explained Jaisi. “That is now phosphorus ending up in our waterways causing water quality issues.”
Jaisi compares a waterway taking in phosphorus to a person’s diet. Just like it’s best to consume your favorite foods in moderation, plants benefit from the right amount of the element, absorbing it through their roots. But just like when you overindulge, too much phosphorus can mean an adverse impact on ecosystems. In certain cases, oxygen is removed from water bodies, creating a “dead zone”.. An explosion of growth in aquatic plants and algae can lead to poor water quality, spelling bad news for aquatic life and contaminating drinking water.
Knowing the location and the quantity of pollutants is essential for any remediation efforts. Phosphorus in the environment is present in two forms—organic and inorganic. Scientists measure isotopes of inorganic phosphate oxygens, but there was no such method to measure isotopes of organic phosphate. In July 2024, Jaisi and Tony Hollenback, a recent Ph.D. graduate, published research on a new method to track pollutants in the environment.
To achieve these outcomes, Jaisi measured the isotope fingerprints of organic phosphate molecules using advanced mass spectrometry techniques. Specifically, Jaisi’s team used an Orbitrap isotope ratio mass spectrometer, an advanced instrument that only UD and eight other U.S. research laboratories possess.
In traditional soil science research, the focus was on how to grow more food in soils. Jaisi points out that many of the very basic scientific questions about phosphorus chemistry were absent from mainstream research. In the past few decades, non-traditional soil scientists and environmental biogeochemists sought to pinpoint different phosphorus sources and mechanisms. They analyzed uptake by plants, redistribution within different compartments in soils; and loss out of agricultural soils to open waters.
Jaisi is now turning his focus to two major lines of research. First, he is interested in developing sustainable fertilizer products like nanofertilizers. These products are at least equally good as conventional fertilizer for plant nutrition, but are more beneficial to the environment. This is because these products are designed for plants to take in a sufficient amount of phosphorus but with minimal nutrient loss. Second, he seeks a high resolution understanding of the element’s biogeochemical processes in the soil. These focus areas bring his research towards a holistic understanding of soil reactions that control the phosphorus cycling in soils and uptake by plants.
Jaisi explained, “The idea is for technological intervention, for example, to use that knowledge to either suppress or promote the particular reaction, so that the intended outcomes of either higher plant uptake or decreased loss of phosphorus from soil can be achieved. Compare it to gain-of-function research in viruses and bacteria that help find treatments for infectious diseases.”
Katie Peikes, communications specialist in the College of Agriculture and Natural Resources, contributed to this story.