I found only few literature about the fertilizer requirement of Chokeberry. There is a huge difference in their recommendation among these papers. Thus, I am looking for more references or advice in this regard.
I'm not a specialist, but meybe this will be useful:
K. Skupień, J. Oszmiański 2007; The effect of mineral fertilization on nutritive value and biological activity of chokeberry fruit, "Agricultural and Food Science", 16(1): 46-55.
http://www.mtt.fi/afs/pdf/mtt-afs-v16n1p46.pdf
K. Skupień, I. Ochmian, J. Grajkowski 2008; Influence of mineral fertilization on selected physical features and chemical composition of aronia fruit, "Acta Agrophysica", 11(1): 213-226.
A. Kokotkiewicz, Z. Jaremicz, M. Luczkiewicz 2010; Aronia plants: a review of traditional use, biological activities, and perspectives for modern medicine, "Journal of Medicinal Food", 13(2): 255-269.