CRANBERRY NUTRITION: ZINC

Zinc response of cranberries (Vaccinium macroncarpon Ait.) was studied in nutrient solution cultures under greenhouse conditions. Two techniques were used for the study: (1) rooted cuttings were grown for 10 weeks in cultures with zinc concentrations ranging from 0 to 0.4 ppm, (2) rooted cuttings were grown for 8 weeks in complete nutrient solutions containing 0.05 ppm zinc, after which they were transferred to solutions minus zinc.

Shoot growth increased rapidly with an increase in shoot zinc concentration from 7 to 15 ppm, with no further increase in yield as concentration increased to approximately 50 ppm. These data support a critical zinc concentration of 13 ppm in cranberry shoot tissue.

Normal growing cranberry plants developed zinc deficiency symptoms about 2 weeks after transfer to minus zinc nutrient solutions. These symptoms appeared as a reddening of the newly developed leaves and stem with an occastional red streaking in older leaves. The symptoms became more severe with time.