UNIVERSITY PARK, Pa. — A nationwide team of agricultural scientists, including researchers at Penn State, has launched a decision aid that provides an unbiased, science-based interpretation of soil test phosphorus and potassium values for crop fertilization.

The Fertilizer Recommendation Support Tool — referred to as FRST — represents a significant advancement in soil testing for phosphorus and potassium, according to the researchers. Using data from across the U.S., the tool is designed to enhance nutrient management, with an eye toward potentially saving farmers millions of dollars annually while reducing excess nutrient losses to the environment.

The new web-based tool is the result of collaboration among more than 100 soil science and agronomic professionals representing nearly 50 universities, four divisions of the U.S. Department of Agriculture (USDA), several not-for-profit organizations and one private sector partner. The team noted that this diverse partnership underscores the collective effort and expertise invested in the development of FRST.

Penn State’s College of Agricultural Sciences is represented on the project by Daniela Carrijo, assistant professor and extension specialist in grain crop production; Charlie White, assistant professor and extension specialist in soil fertility and nutrient management; and John Spargo, associate research professor and director of Penn State’s Agricultural Analytical Services Laboratory.

“We are very excited about the launch of the decision support tool,” Spargo said. “It has the potential to significantly improve our ability to evaluate soil test correlation and determine fertilizer nutrient needs at a time when getting that right is more important than it ever has been.”

Deanna Osmond, soil science researcher at North Carolina State University and one of the group’s leaders, noted that until now, soil fertility faculty in each state worked independently.

“But for farmers who work across state lines, it’s difficult to compare or assimilate multistate guidelines,” Osmond said. “Our goal is to improve the accuracy of nutrient recommendations through independent, scientifically developed nutrient management best practices that farmers can believe in and adopt.”

Currently, FRST provides critical phosphorus and potassium soil test values, indicating where there is no expected yield increase from phosphorus or potassium fertilizer application. In the next phase of the project, the tool will provide research-based phosphorus or potassium rate response information to assist farmers in selecting the minimum fertilizer rate expected to produce maximal crop yield.

The current version, FRST v1.0, includes data from nearly 2,500 phosphorus and potassium trials for 21 major agricultural crops, mostly corn and soybean. The tool includes a map of the U.S. that shows the location of phosphorus and potassium trials represented in the database. This map can be used to identify where the need for additional research data is greatest.

The database was constructed from both historical and current research data and includes trials from 40 states and Puerto Rico. The team plans to expand to other crops, cropping systems and nutrients, such as sulfur.

The research team pointed to several key features of FRST:

• Data-driven: FRST utilizes a dynamic database of soil test correlation data that is constantly updated to improve testing confidence.
• Crop specific: The database currently covers 21 major commodity crops.
• Geographically diverse: Includes published and unpublished trial data from 40 states and Puerto Rico.
• Unbiased: Blended data removes political and institutional bias in soil test interpretation.
• Scientifically sound: Data represents a minimum dataset that provides reliable outcomes.

Nathan Slaton, soil science researcher at the University of Arkansas and a leader on the project, explained that the FRST project has accomplished two important objectives to advance phosphorus and potassium management for crop production.

“The first objective was developing a national database to archive soil test correlation and calibration research ensuring that research information that supports crop fertilization recommendations is not lost as scientists retire,” Slaton said. “The second is providing a tool that anyone can use to review the research results relevant to their crops, soils and geographic area to check their soil-test-based fertilizer recommendations.”

Hosted in a neutral space with common access, FRST fosters collaboration and innovation in soil fertility research, paving the way for future advancements in nutrient management, according to Greg Buol, of North Carolina State University, who has provided database and programming support.

“The design of FRST always has been focused on the end user being able to use the tool easily and understand the results,” he said.

Spargo added, “We believe that FRST will not only benefit growers by improving return on investment and conservation practices but also contribute to global sustainability."

For more information about FRST and how it can transform nutrient management for farms and organizations, visit https://soiltestfrst.org and select “Tool.”

The USDA Natural Resources Conservation Service, USDA Agricultural Research Service, USDA National Institute of Food and Agriculture and OCP North America have provided funding for this project.