Potassium deficiency in agricultural soils is a largely unrecognized but potentially significant threat to global food security if left unaddressed, finds new research involving researchers at UCL, University of Edinburgh and the UK Center for Ecology & Hydrology.
There is still plenty of potassium its just about cost of extraction and shipping.
The phosphorus supply is much more concentrated mostly in morrocco & western sahara , we high graded the low contaminant stuff already and are getting nastier P with more heavy metals. Africa is almost wholly P deficient and population is supposed to rise by 3+billion, yet they have the highest fertilizer costs in the world because supply chains and transport dont penetrate cost effectively with roadblocks every 100km across much of the continent that require bribes. so paradoxically the continent with like 80% of global P reserves and the most desperate need gets the least. Even governments and corporations doing land grabs have had trouble getting production up to standard and the costs of inputs in africa .