SALEM, Ohio — For decades, farmers have been measuring the quality of their soil by the nutrients found in that soil. But, thanks to research by a laboratory in Maine and a U.S. Department of Agriculture scientist in Texas, there is a new test that determines overall health of the soil.
Known as the Soil Health Nutrient Tool, the test measures the soil's carbon dioxide rate, microbial active carbon and water soluble carbon. Each of these is an indicator of the soil's biological health — its structure and its ability to use nutrients.
The test came about after a chance meeting between two researchers, Will Brinton, president of Woods End Laboratories in Maine, and Rick Haney, a soil scientist with USDA's Agricultural Research Service in Texas. The two men joined forces in 2005, to find a way to "manage soil health in a laboratory."
The result is a test that goes beyond just nutrients, and measures the quality, or the health of the soil system, Brinton said, as it relates to soil biology, structure and porosity.
The test relies on the same kind of core soil samples farmers already take and is currently offered in three locations: Woods End Labs in Mount Vernon, Maine; Brookside Laboratories in New Bremen, Ohio; and Ward Labs of Nebraska.
If you want the nitty-gritty technical details, the test methods "use green chemistry, in that the soil analysis uses a soil microbial activity indicator, a soil water extract (nature's solvent) and H3A, a soil extractant that mimics organic acids produced by living plant roots to temporarily change the soil pH, thereby increasing nutrient availability," said Haney, in a released statement.
The end result is the Soil Health Score, which Haney said "represents the overall health of the soil system," and combines five independent measurements of a soil's biological properties.
Farmers and turf management companies can use the health score to determine what nutrients need applied, but also what nutrients are already in the soil, possibly from a previous nutrient application.
This can help save money, explained Brinton, and it also could help reduce nutrient overloading — something that can be harmful to the crops and to the environment.
The main goal, Brinton said, is to "save farmers money on unneeded fertilization while at the same time taking stock of your soil's health."
Luke Baker, agronomist with Brookside Laboratories, said the test allows farmers and turf managers to document something they already knew existed, but didn't have a way of calculating.
"We have largely ignored the biology of the soil in the past when making soil nutrient recommendations," he said. "We know that it is present and cycling nutrients, but we never accounted for it because we didn't have a way to do it. The soil health tool allows us to do this."
Brookside has only offered the test since Jan. 1, but has already performed 300-400 tests. Baker expects many more once the weather improves and more farmers hear about the benefits.
The test will not replace standard soil testing, but it definitely "allows us to see things that we never accounted before," he said.
Spectrum Analytic, of Washington Court House, Ohio, offers the Solvita Test, which is part of the overall Soil Health Test and measures soil respiration, which is an indicator of soil life.
Bill Urbanowicz, agronomist for Spectrum, said most of his clients are in the turf management business, although a few have been farmers. The nice thing about this test, he said, is it measures microorganism activity in the soil.
This shows the turf operator what type of response he's getting for the nutrients he's applying, and the results he's getting for his chosen type of tillage and crop system.
Urbanowicz said this test can go a long way to show the value of cover crops, which are believed to be one of the best ways to maintain soil structure and soil biology.
Farmers have long thought that conservation tillage and cover crops make good soil, but now, Urbanowicz said, it's a claim that can be "measured and quantified."
The results help farmers and turf managers make management decisions about different pieces of land, benefiting them economically and environmentally.
Brinton hopes that as the soil health tool catches on, more commercial labs will be interested in offering the test. Since it relies on the same type of sample as other soil tests, it is not hard to conduct.