“…The USA, Canada, and Poland are countries where highbush blueberries are widely cultivated, therefore advanced experience has been accumulated there. The researchers from these countries (Haynes & Swift, 1985;Sanderson, Carterl, & Ivany, 1995;Ochmian, Grajkowski, Mikiciuk, Ostrowska, & Chelpinski, 2009) consider that the optimal soil reaction pH KCl for highbush blueberries is 4.2-4.8. In very low pH KCl environment (lower than 3.4), plants suffer from Ca deficiency; if reaction becomes less acid (pH KCl 3.4-3.8), plants gradually recover but productivity (yield of berries) is very low (Hart, Strik, White, & Yang, 2006;Hancock, 2009).…”