Hands on Agronomy by Neil Kinsey.  I read that in the 1990`s when some coops still didn`t know the difference between P & K and thought the only reason a soil was acidic was that it needed lime.   Now everyone has jumped on the Albright balanced soil system.   I see Neil Kinsey is going to be a speaker at the Hefty brothers event in March, like to attend but March is busy.