Responses to phosphorus and potassium fertilizers are not always noticeable in the year of application. However, some phosphorus and potassium are removed with the bean crop. The recommended broadcast rates of phosphate and potash are given in the nutrient recommendation table. If applied as a starter, the recommended placement of the fertilizer is in a band 2 inches to the side and 2 inches below the seed. Zinc deficiency can be intensified if phosphate is applied as a starter, so some zinc should also be added to the starter fertilizer to prevent such a possibility.
Dry bean is very susceptible to fertilizer salt injury.
The application of approximately 20 pounds of P2O5 per acre will increase the Olsen phosphorus test by 1. Likewise, the application of 5 pounds of K2O per acre will increase the potassium soil test level by one, except in sandy soils within the beach area, where potassium fertilization of each crop is a better option. Coarse, sandy textured soils cannot be economically fertilized to raise potassium levels because of leaching. Suspect areas are generally limited to sandy soil, especially if high calcium carbonate levels extend to the surface, and low organic matter areas where top-soil has been removed such as in leveling for irrigation and drainage ditches. Some edible dry bean varieties also are more susceptible than others to zinc deficiency.