The effects of boron fertilization on yield of broccoli, cauliflower and cabbage were evaluated through a field experiment carried out on a sandy soil low in available boron. Five boron levels (0; 2; 4; 6; and 8 kg ha-1 B as borax) were applied in broccoli, cauliflower and cabbage using a factorial scheme and a randomized block design with three replicates. Organic manure and chemical fertilizers, including borax, were applied in the planting furrow before seedlings transplant and plants were harvested 63 to 93 days after planting date. The yield intervals obtained with broccoli, cauliflower and cabbage varied according to the following intervals: 16.9 to 20.5 t ha-1, 21.6 to 29.6 t ha-1 and 40.5 to 46.3 t ha-1, respectively. The increase in production observed in broccoli and cabbage yield was linear with boron levels and the boron effect on cauliflower yield was quadratic. For maximum cauliflower yield (30 t ha-1) 5,1 kg ha-1 of B were necessary. Broccoli and cabbage were less sensible than cauliflower to boron deficiency and toxicity. Quality of the curds decreased when 2 or 6 kg ha-1 B were applied in cauliflower fertilization.
Brassica oleracea var. italica; B. oleracea var. botrytis; B. oleracea var. capitata; micronutrient; leaf diagnosis; yield
