The SHIP that tracks soil health
September 1, 2023 | Bethany Baratta
A farmer’s standard soil fertility test provides information relevant to current field soil nutrient conditions, but that’s different than overall soil health. Soil health includes soil functions that sustain its productivity. Farmers may be interested in obtaining a free, soil health metric that can be calculated from soil organic matter, a measurement common in soil fertility testing, coupled with the sample location.
An Iowa Soybean Association (ISA) tool, called the Soil Health Interpretation Portal (SHIP), was developed to help farmers easily learn how well their soil scores on one soil health metric without additional testing or cost, and to be able to compare it to the scores of other soils with similar characteristics to their own. The tool both uses and calculates the USDA’s Soil Health Assessment Protocol and Evaluation (SHAPE) soil organic carbon scores for each sample location. These scores use 30-year average weather and underlying soil texture information to compute a score of how well each sample area is functioning relative to its estimated potential.
The SHIP also features two databases of lab results and SHAPE scores from soil health and nutrient studies conducted by ISA and the Iowa Corn Growers Association. The standard soil test database includes data from over 850 sites sampled by farmers in 2011 in fields with mostly conventional management practices as part of a Nutrient Benchmarking project. The soil health database includes soil health test results from 59 Iowa fields practicing no-till and containing strips of cover crops starting in or continuously in studies between 2014 and 2021.
“The tool features three soil health management practice choices that farmers can select or deselect to see how fields that do or don’t employ them differ in test and soil health scores,” says Suzanne Fey, an analyst for ISA’s Research Center for Farming Innovation (RCFI).
The SHIP adds one more dimension to the data by summarizing results by “physiographic subregion” of the state with similar soil development and topographical characteristics, so farmers are comparing their scores to those of others on a more level playing field, Fey says.
“We see in the average SHAPE scores by subregion that the percent of backslope appears to matter when developing realistic expectations for soil health improvement potential.”
Evaluating your soil
SHIP users can temporarily load their own data for a “Quick Look” or set up a free account to obtain more detailed analyses and compare results over time. Quick Look users who temporarily provide location information can choose to anonymously donate their data to the benchmarking database or simply exit the platform releasing their data without donating it.
Visitors who upload spatially referenced soil test results will enable the tool to generate a report describing their physiographic subregion and receive a graph of the SHAPE scores for each sample location identified with no requirement to donate the data or include any management information, just the option to do so.
“We know a lot more about the physical and chemical properties of the soil; the biological component is a developing science,” says Hillary Olson, state soil health specialist for Iowa natural resources Conservation (NRCS) and a member of the advisory team guiding the tool’s creation and usage. Iowa NRCS is a funding partner for the online tool.
“As with any living system, there can be fluctuations in the results due to things like weather and management.”
Adjusting management decisions
The tool provides a unique comparison infrastructure featuring physiographic subregions with differing glacial development history and subsequent soil and topographical characteristics. The map was developed in 2019 at the Geospatial Laboratory for Soil Informatics at Iowa State University and was the basis of ISA RCFI Spatial Analyst Josh McDanel’s master’s thesis.
“Understanding the characteristics of subregions, like the Des Moines Lobe, for example, help inform management decisions,” McDanel says, noting various soil health characteristics within sub-regions.
“There are four physiographic sub-regions within the Des Moines Lobe. Some fields have slightly sandy or slightly clay soils. Each set of characteristics has an impact on management and can affect soil health.”
A sandier soil erodes quicker than loamier, siltier-textured soils, for example. So growing cover crops and reducing tillage on these soils slows erosion.
Growing soil insights
While the portal offers information about ways to improve the results of tested soil health metrics, retention of topsoil is perhaps the most effective way to maintain soil productivity, Fey says.
“No-till farming and cover crop incorporation are effective practices to help retain Iowa’s rich topsoil,” she says. “These practices also, along with manure application, provide beneficial conditions for microbial actions in the soil to sustain agricultural production.”
Fey says farmer participation in data donation through the tool helps grow insights available to all farmers. “As the database grows, we will enable more summarization options,” Fey says. “Our goal is to study Iowa’s soil health patterns over time while tracking the impact of management practice systems on results.”
The portal is available at shportal.iasoybeans.com.