Yes this is the affect of an inorganic like Potash, but I'm trying to reconcile what is assumed happens at the soil level contrasted with its use in foliar.
My basic point is you want organics to be not water soluble. You want the microbes to break them down and chelate the ions with organic acids or aminos as it reduces the amount pf energy the plant needs to convert those elements into plants
You want the soil to act kinda like the stomach pf the plant...digesting and doing part of the work for the plant. Its the energy trade...the plant provides energy to the microbes which, in turn, provide minerals in a form that saves the plant energy. Soluble ions short circuit that relationship
I even believe you can get insolubles into the plant via foliar if you micronize them. Leaf bacteria will make them available in chelated form.
Also why you want mannitol in your kelp...for the chelation.
Albrecht said it in the 40s...not soluble but available.