In your article by Susan Patterson, Maaster (sic) Gardener "Deformed Beets: Reasons Why Beets Are Too Small Or Deformed" it is suggested that adding phosphorus to gardening soils can lead to better beet root development. Where does this recommendation originate and how does it stand when tested against the advice in a series of articles on Horticultural Myths, by Linda Chalker Scott, found at the following link? See articles under "Fertilizers" at: https://puyallup.wsu.edu/lcs/
Is Phosphorus Really Good for Beet Root Development?
Phosphorus is known to stimulate root growth; however, most soils have adequate levels of phosphorus. I'm with you: if a soil test doesn't show deficiency, then adding phosphorus isn't necessary and is potentially harmful when it runs off into water sources. It also moves very slowly through the soil. Topdressing with phosphorus will not help the current season's crop.