Project aims to define national soil health benchmark

A new national project aims to give farmers a clearer way to measure and compare soil health. The initiative, called Probing Our Country’s Soil Health, is led by USDA’s Agricultural Research Service (USDA-ARS), working in partnership with the Natural Resources Conservation Service (NRCS) Soil Health Division.

The project will create a free, user-friendly Soil Health Assessment Protocol and Evaluation (SHAPE) tool, providing insight into soil health management with an eye toward improving yield.

USDA leadership has identified soil health as a national priority tied to long-term productivity and conservation. The SHAPE project aligns with that goal by building a consistent national benchmark for soil condition.

For producers seeking measurable standards rather than general principles, the project should offer a clearer reference point for soil performance.

Newell Kitchen, a soil scientist and agronomist and owner of AGES (Agronomic Geologic and Environmental Services) and a project lead, said the initiative will help move soil health from a concept to something farmers can quantify.

Soil health, said Kitchen, has often been discussed in more general terms, and soil fertility testing has been more about addressing what’s missing from a plant nutrition standpoint to know how much fertilizer to apply.

“The SHAPE tool is trying to move soil health more to a quantitative measure,” Kitchen said.

Researchers aim to wrap up the project, launched in September 2023, in August 2028.

Research work ahead

The labor-intensive task of gathering approximately 10,000 soil samples from farms and ranches across all 50 states is ongoing. The samples will come from a wide range of soil types, climates and production systems, including annual crops, perennial horticulture, pasture and rangeland.

“It’s a pretty long walk to get to that,” Kitchen said. “And the cost of this thing is not trivial.”

Participating fields are typically sampled in two to three locations. Samples are taken from the top six inches of the soil using a standardized national protocol. Sampling teams focus on the dominant soil types within a field rather than conducting high-density grid sampling, Kitchen said.

“If we go to grid soil sampling — with the costs associated with many of these samples, farmers would walk away in a second,” Kitchen said. “You’ve got to start somewhere.”

Participating producers are also asked to complete a management survey. The survey asks farmers about their management practices over the past two years and general trends over the past decade. The survey’s questions focus on tillage, crop rotation, cover crops, manure use and other practices known to influence soil health.

Field teams also record site-specific details at the time of sampling, such as the crop that is currently growing and surface residue conditions. The collected samples are then sent to a lab in Columbia, Missouri, that is overseen by USDA employees.

Technicians analyze each sample and compile data on 24 soil health measurements. Those measurements are grouped into broader categories that reflect biological, chemical and physical soil properties, Kitchen said.

Recruitment remains open

To date, approximately 30% of the targeted sampling has been completed. Kitchen said recruitment has been strongest during winter months, when farmers have more time to consider participation. 

Each state has a general sampling target based on land use patterns, soil variability and agricultural intensity.

Program recruitment remains open in most states, with outreach efforts aiming to meet sampling targets before the next phase of development begins.

Matt Yost, an agro-climate Extension specialist and assistant professor at Utah State University, is part of the project’s recruitment team. Responsible for coordinating field recruitment efforts in the western U.S., he is encouraged by the interest the project has garnered.

“We get a lot of really excited and willing participants,” he said. “People really care about soil health.”

Value for potato growers

The sampling does not single out potatoes as a stand-alone category. Instead, fields are evaluated within broader land-use systems, such as annual cropping systems. Potato rotations are captured through the management survey.

Kitchen said the value for potato producers lies in benchmarking. Once the enhanced tool is available, growers will be able to compare soil health results from their own fields to similar soils within their region and climate zone.

NRCS is a primary funder of the project. With staff located nationwide, NRCS personnel may also use SHAPE as part of conservation planning and soil health technical assistance.

The tool is not intended to provide direct yield prescriptions, however. Instead, it identifies potential gaps between current soil conditions and higher-performing soils in the same group. From there, producers may consider management practices that could help close the gap.

Farmers participating in the project receive their soil health test results as well as interpretation based on the existing SHAPE framework. As more data is added, the recommendations will become more refined. Kitchen expects an updated version of the tool to be available as early as 2029.

Kitchen said precise field locations, survey responses and personal information are not shared without the farmer’s permission. Public maps show only generalized locations, and identifiable data is protected under project agreements.