BORON NUTRITION OF BROCCOLI, BRUSSELS SPROUTS, AND CAULIFLOWER GROWN ON PRINCE EDWARD ISLAND SOILS

Broccoli (Brassica oleracea L. ssp. italica Plenck., cult Waltham 29), Brussels sprouts (Brassica oleracea L. ssp. gemmifera, cult Jade Cross), and cauliflower (Brassica oleracea L. ssp. botrytis, cult Snowball Y) were grown at four locations on Prince Edward Island with five levels of applied B at each location. The levels of applied B were: 0, 0.56, 1.12, 2.24, and 4.48 kg B/ha. No B deficiency symptoms, with the exception of hollow stem in cauliflower and broccoli, were noted. The incidence of hollow stem in these crops was not affected by applied B. The B concentration of tissues of all three crops was generally lower late in the growing season than earlier. Boron levels in the first tissue samplings were 13–70, 13–101, and 8–97 ppm in broccoli, Brussels sprouts, and cauliflower, respectively, and were found to be in the sufficiency range. A hot-water-soluble B content of 0.34–0.49 ppm in soil was sufficient for optimum growth of the crops. No B toxicity was observed even when the rate of applied B wa...