Plants require 12 mineral nutrients that are essential for their growth and development. A shortage of any one element will result at best in stunted and poor growth. The plant however needs the various minerals in differing amounts. Phosphorus, together with Nitrogen and Potassium, being consumed in relatively large amounts, is considered one of the macro elements.
#phosphorus occurs in nature and is crucial for growth. As Walter Reeves,#MG Cooperative Extension master gardener teacher at the Atlanta Botanical Garden, taught us, here's how to read a fertilizer bag:
N P K "UP, Down, AllAround":
N=Nitrogen which greens plants UP, gives them top leaf/stem growth for more photosynthesis so they can feed themselves...
P=phosphorus, which plants need to go DOWN with root development to survive drought, provide a strong foundation for top growth and for bloom development...
and K=potassium, which is crucial to ALLAROUND vascular growth.
I'm no soil scientist. "UP-DOWN-ALLAROUND" is single most important thing I learned in MG training.
The finer points of how addding highly concentrated phosphorus fertilizer to alkaline soil creates a concrete-like farming disaster in developing countries and elsewhere, I learned from Bill Mollison in training to be a certified #permaculture designer.
Most important sentence of the article is last, of course (Peek at the happy ending first!)
"It may be well worth your while conducting a soil test before amending your soil. If you are in doubt, it would be best to rely on organic matter only, excluding chemical fertilizer altogether."