Originally Posted by Kiril
You have misunderstood and misrepresented the formula, which is the reason for your confusion.
According to the formula the bracket portion will not differ greatly from the number 1 because 6.6 happens to be an ideal soil pH. If 6.6 is taken as an ideal pH level then the bracket portion is equal to 1. My confusion lies in the simplicity of the formula and questions its' accuracy. I was merely pointing out that if the target pH varies greatly from 6.6 then the formula makes little logical sense as a way of providing one reason why I distrust this formula. I am asking if this is the standard formula or what others use, although I understand that formulas vary greatly from place to place.