In soils that can range in pH from the low 4's to 7, depending on the location and liming history, deficiency of Zn, B, and Mo coupled with the soil acidity complex of Mn toxicity had been previously identified as severe limiting factors in producing quality Brassica crops. Fertility studies on fall and spring planted Brassicas focused on the effect of including/not including micronutrients during various phases of growth when NPK preplant fertilizer was reduced. Differential responses to reduction in preplant NPK and applications of micronutrients was found to be dependent on planting time (fall or spring), species of Brassica planted and cultivar. Nutrient uptake in leaf blades and petioles was followed. In broccoli timing of micronutrient applications significantly affected the harvest period length. Broccoli final yields of the B, Zn and Mg treatments were found to contribute ≈75% to 80% of the final yield of a full range micronutrient solution.
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