The article mentioned that in most soils P and K levels are adequate for blueberry and do not require further amendment. I've found that lawn fertilizers with most of the N coming from ammonium sulphate and various urea compounds works well. These fertilizers often have low levels of P and K. Many states and municipalities have outlawed the use of P for homeowner lawn fertilizer, algae blooms. K is most likely to be deficient on sandy soils.

Sulphur is also added to the lawn fertilizer blend I use and helps maintain low pH. My soil is naturally acidic and ideal for blueberries but my irrigation water is neutral.

My bushes are field planted not container culture. I suppose soil less container culture may require more attention to nutrients other than N.

Also if you are really pushing those bushes for max yield year after year more inputs will eventually be required.