morelifeparty

I suspect there might be some error in your math? I haven't seen the removal rates expressed in lbs of grain removed before, but I guess it doesn't matter...IF the formula was expressed originally in lbs of nutrients removed per lbs of grain. Or, what institution do you cite that has that low of removal prediction?

However, I believe the average removal rate (averaged between Purdue & U of IL) commonly used here (IL) is as follows:

P = .43 lb/bu of corn. Keep in mind, that's P while we normally buy DAP, which is only 46% P (or P1 or whatever it is...commonly called "P")
K = .28 lb/bu of corn. However, here in the midwest we commonly buy 0-0-60, which is only 60% K.

So, as others have pointed out, we actually remove 0.93 lb of DAP per bu of corn removed from the field.....or 93# of DAP per 100 bu of corn removed.
Potash = 0.47 # of 0-0-60 per bu of grain removed from the field......or 47 # per 100 bu of corn removed.

That's how I do it here irregardless of our tillage. Formula is slightly different w/soybeans.