If you are reading this, you are probably interested in balancing the minerals in your soil so that you may grow nutrient dense food. We find the intricacies of soil analysis fascinating, but we recognize that many people need help determining what their soil needs.
We’ve developed an online app, OrganiCalc, that will provide you with a list of recommended soil amendments, based on the results of your soil test, to balance the minerals in your soil. We only recommend amendments that may be found on the OMRI list of approved materials for organic certification.
Soil test methods vary. Different labs get different results using the same test procedure on the same soil. The recommendations given by OrganiCalc are tuned to the Mehlich 3 soil test procedure as done by Logan Labs.
But before you decide which soil test lab to use, make sure your soil is not “fizzy”. Most aren’t, but if yours is, you’ll need to handle it differently.
What is calcium carbonate and why would it be in my soil?
Calcium carbonate is in limestone and agricultural (ag) lime. It may be present naturally in your soil, or it may have been recently added. In either case, soils containing it require special testing.
How do I know if I might have free calcium carbonate in my soil?
If you answered “yes” to any of these questions, you ought to go ahead and do a fizz test.
Doing a fizz test is easy.
The amount of fizz is roughly proportional to the amount of carbonate in the soil. If you have to listen closely to hear it, it is weak. If you can see lots of bubbles, it is strong. Medium is in between.
Calcareous soils can be very productive, but require special handling. If you have fizzy soil, we recommend a test specifically for calcareous soils. The Soil Science Society of America recommends a neutral potassium chloride extractant for calcareous soil as it does not dissolve any calcium carbonate but only extracts available Ca and Mg. Other tests include the elevated ammonium acetate pH 8.2 or 8.5 tests.
It’s best to find a test lab near you.
We now have an alternative that allows you to use OrganiCalc.
If your soil fizzes, ask the lab to do an additional Ammonium Acetate pH 8.2 (AA8.2) test as well as the standard Mehlich 3 test on your soil. If you are using Spectrum Analytic, be sure to also ask for the sodium M3 test.
When you get your test results, follow this procedure…
Step 1: If you use Logan Labs, determine the TCEC using our calculator here. Enter the Calcium value from the AA8.2 test and the Mg, K, Na and pH from the Mehlich 3 test. The calculator will show you the TCEC to use for OrganiCalc.
Step 2: Enter your test results into OrganiCalc but use the Calcium value from the AA8.2 test instead of the one from the Mehlich 3 test. If you used Logan Labs, enter the TCEC from the calculator (see step 1).
If you are going to use Logan Labs, download their worksheet here: http://www.loganlabs.com/doc/HowToFillOutLoganLabsWorksheet.pdf
Thank you for your download, we hope you are satisfied with our software.