I've gotten a recommendation for amending my soil. It calls for 1 cup calphos (soft rock phosphate) which is 0-3-0. It says it has 3% available P with 15% or so total P. I've locally source an amendment called Phosul. It's labeled 0-16-0. But it says on the bag 16% total P and 6% available P. But it's labeled 0-16-0. So if I'm subbing out the phosul for the calphos I should do the math based on it having 6% available P and ignore that it's labeled 0-16-0. 1 cup of calphos at 3% available P would be .5 cup of phosul at 6% available P to equal the same amount of available P. If I do the math by the label 0-16-0 vs 0-3-0 it would be .2 cup of phosul (rounded up) to equal the same amount. I'm new at this. Is it just labeling differences between different manufacturers? I should trust the 6% available P, correct?
Here's a pic of the phosul bag
Thanks guys
Here's a pic of the phosul bag
Thanks guys