Solvita SLAN test ran on several Piedmont soils reveals large differences in a hidden amino-N pool

A new soil test from Solvita called SLAN reveals a hidden pool of organic nitrogen that is “just beneath the surface, and seems indicative of soil improvement”, says developer Will Brinton.  The SLAN test like the Solvita CO2-test takes only minutes to set up and is read after 24hrs with a digital reader.

Continuous cultivation of soils depletes humus and soil biology, and estimates are that USA soils are presently 30-70% depleted. Yet, normal soil nutrient tests don’t reveal the loss.  Solvita’s mission is to show other soil factors such as CO2 respiration that may be important to long term fertility and soil health.

The Piedmont (North Carolina) region has soils that can become extremely depleted but are very responsive to improved management.  It seemed like a good place to pre-test SLAN. USDA-NRCS in Greensboro NC submitted several soil samples and Woods End Labs ran the new test. The results clearly showed effects of the differing management practices in terms of this hidden pool of amino-nitrogen (see image).  Truck farming and continuous tobacco soil showed virtually no organic-N pool by the SLAN test, but soils cover-cropped and no-tilled did. Topsoil from a unique 40-year no-till farm showed high levels of SLAN. The USDA team included a virgin prairie soil from Nebraska which showed similarly elevated levels of amino-N, “so we know SLAN reveals a soil quality factor”, says Brinton.

Testing for Amino-N in soils is not new, although it may be  the first time such a simple approach using Solvita has been tried. According to Brinton, who studied in Europe in the 70’s, it was Russian scientists who first highlighted humus’s amino-N content, “which is what we are measuring”.  The amino-N is set free after treating soils with alkali, a process used to release humic acids. Labs already running Solvita CO2 soil tests can implement SLAN without any new equipment.