A new method of soil testing that measures the drying and rehydration cycles in farm ground could help no-tillers use fertilizer more efficiently and even choose the best cover crops to seed ahead of the next crop.

The “CO2 burst” test measures soil microbial respiration. These drying and re-hydration cycles represent the absorption and release of large amounts of carbon, which is tied to the productivity of flora and vegetation.

The new 24-hour rapid test, commercialized by a Maine-based company named Solvita, can even be combined with other current organic-nitrogen and organic-carbon tests to calculate a “soil-health calculation” of 1 to 50 — a number that describes a farmer’s current soil-health level and allows them to gauge the effects of management practices.

Omaha, Neb.-based Midwest Laboratories has begun offering a biological respiration and nitrification (B.R.A.N.) test that is based the CO2-burst method. An estimated 40 labs are now offering the respiration test.

Biological Pump. Solvita officials say natural drying and re-hydration cycles in soil serve as a “biological pump” that delivers soluble carbon to microbes and nutrients to growing plants.

The CO2-burst analysis is performed using a soil-microbial activity indicator, a soil-water extract and H3A, a soil extractant that mimics organic acids produced by living plant roots.

Rick Haney, a soil scientist with the USDA’s Agricultural Research Service in Temple, Texas, helped research and compose the protocols for the new test. He spent more than a decade researching the organic acids plants release into the soil that indicate what nutrients…