Would appreciate opinions, comments and corrections. I am truly working well out side my knowledge comfort zone. Well into my understood zone of incompetence.

My assumption - wild supposition -
It requires a soil test of 170 ppm K to insure high alfalfa production, with 2.50% tissue analysis.

On my 50 CEC soil 522 ppm K (50 CEC X 10.44) to realize the 2.50% tissue analysis.

170 ppm K is 32.6% of 522 ppm K, or roughly 2/3s.

Most available K,to the crop, is in the Exchangeable K pool, with only 1 to 10 ppm K being in soil solution. The book tells us only 1% to 2% of the total K pool is in this Exchangeable Pool. This pool holds this K pool to the clay particles by electron attraction and mechanically by the clay platelets. The cations held by electron attraction are fairly available but the mechanically held cations are less available to the plant, but are reported by the soil testing chemistry.

So far so good?

A complication that is beyond me is the calcium and magnesium with their two positive electrons, while K has one. This is also a high pH soil with more than 10% free lime, possibly 20% free lime. I would think magnesium and calcium would hog all the electron attraction points on the clay surfaces, leaving no room for potassium.
Is it possible potassium held within the clay, is more available than I assumed?

The only thing I do know for sure is, I really do require 2 to 3 times the amount of potassium that is generally assumed to be adequate levels of K.
I do wish some agency would or has done replicated plots on similar soils and have the results measured down to the micro level. Something I do not have the time, energy, or competence to attempt.

Again opinions, comments and corrections are welcome.