Digitized access and research-based data eliminate guess work for farmers nationwide

Gurpal Toor and Colleague

Image Credit: Edwin Remsberg

April 12, 2024

A national collaborative, including a University of Maryland nutrient management and water quality specialist, has released FRST (Fertilizer Recommendation Support Tool), a web-based decision-aid that provides an unbiased, science-based interpretation of soil test phosphorus and potassium values for crop fertilization. The new tool represents a significant advancement in soil testing for phosphorus and potassium and will be especially useful for farmers who lack knowledge about ‘critical soil test values,’ an important benchmark that determines if additional application of fertilizer will help increase crop yield.

The FRST project is a collaboration of over 100 soil science and agronomic professionals representing nearly 50 universities, four divisions of the USDA, several not-for-profit organizations, and one private sector partner.

The University of Maryland is represented on the project by Professor and Extension Specialist Gurpal Toor from the Department of Environmental Science and Technology in the College of Agriculture and Natural Resources.

Toor noted that “we are excited about the launch of the decision support tool and reduced speculation for farmers. The FRST was developed in response to the pressing need to harmonize soil testing across state boundaries. Using FRST, a ‘critical soil test value’ can be calculated, above which no yield benefit from fertilizer application is expected. At this early stage of the FRST, minimal data have been included from Maryland, as all included data must meet minimum standards, as outlined in Slaton et al. (2022) peer-reviewed article [1]. In Maryland, farmers should continue to use guidance from our unique agricultural nutrient management program to determine application rates for nutrients,” Toor concluded.

In Maryland, there are nutrient management recommendations for each crop, which are determined using our own robust database. Note that FRST is not related to the Phosphorus Management Tool (PMT), which is currently used in Maryland to guide phosphorus applications in high-phosphorus soils.

Key Features of FRST Include:

  • 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 represent a minimum dataset that provides reliable outcomes.

Deanna Osmond, a soil science researcher at NC State University, said 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 multi-state guidelines. 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, the FRST provides critical phosphorus and potassium soil test values. In the next phase, the FRST 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, with the majority as corn and soybean. The FRST includes a map of the US that shows the location of phosphorus and potassium trials represented in the database, which 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 has plans to expand to other crops, cropping systems, and nutrients, such as sulfur.

Nathan Slaton, soil science researcher at the University of Arkansas, noted that the FRST project has accomplished two really important objectives to advance phosphorus and potassium management for crop production. The first 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. The second is providing a decision aid tool that anyone can use to review the research results relevant to their crop, soil, 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. Greg Buol of NC State University, who provided database and programming support, stated that the design of FRST has always been focused on the end user being able to easily use the tool and understand the results.

For more information about FRST and how it can transform nutrient management on your farm or in your organization, visit https://soiltestfrst.org and click on “Tool.” Funding for the FRST project has been provided by the USDA-NRCS, including the Conservation Innovation Grants, USDA-ARS, USDA-NIFA, and industry.


Gurpal Toor, Professor & Extension Specialist of Nutrient Management and Water Quality, University of Maryland


[1] Slaton, N.A., Lyons, S.E., Osmond, D.L. Osmond, Brouder, S.M., Culman, S., Drescher, G., Gatiboni, L.C., Hoben, J., Kleinman, P.J.A., McGrath, J.M., Miller, R., Pearce, A., Shober, A.M., Spargo, J.T., & Volenec, J.J. (2022). Minimum dataset and metadata guidelines for soil-test correlation and calibration research. Soil Science Society America Journal, 86, 19–33. https://doi.org/10.1002/saj2.20338