Ok, I got soil report back and it is calling for 120# N and 40# K2O per acre. How do I go about fertilizing? I know that 13-13-13 is equal in N, P2O5, and K2O but does that mean the bag has 13% of each? So a 50# bag of 13-13-13 would have 6.5 #'s of each element? Not sure what the # value denotes... Also have one are that just calls for 120# N per acre and nothing else. None of my soil is calling for P2O5 for anything I plant.