The lamotte tests are interesting but I am not sure just how reliable they are. Cant tell from reading their website.( and I didnt read all the pdf's they gave) It looks to me that they are testing and recommending materials based on Lbs or PPM. This isnt totally correct if your are trying to improve your soils fertility. For instance, P has shown to become locked up and unavailable to the plants in as little as 8 days in ideal conditions and 4 days in less than ideal conditions. The P is still there and the test results will show that it is still there, it just isnt available to the plant. Test that show results in total nutrients dont necessary tell you that those nutrients are available to the plants. Percent is more reliable than lbs, lbs just tell you how much it takes to get there. At any rate, I would consider the AST15, http://www.biconet.com/testing/ast.html
, instead of the cheaper version, isnt but $200 higher and it checks for more micronutrients than the other versions.