Cauliflower, Broccoli, and Brussels Sprouts Responses to Concentrated Superphosphate and Potassium Chloride Fertilization

Abstract

Abstract Cauliflower (Brassica oleracea var. botrytis L. ‘Imperial 10-6’), broccoli (Brassica oleracea var. italica Plenck ‘El Centro’), and brussels sprouts (Brassica oleracea var. gemmifera Zenk. ‘Jade Cross’) were grown at 0, 84, 336, and 1344 kg of concentrated superphosphate (CSP) (0, 17.5, 70, and 280 kg P) and 0, 67, 268, and 1072 kg of potassium chloride (KC1) (0, 35, 140, 560 kg K) fertilizers per hectare, per application in a long-term plant nutrition experiment. Increasing the rate of CSP increased the concentrations of P, Ca and Mg but decreased K and Zn in leaf blades at midseason. Increasing the rate of KC1 increased the concentrations of K and Zn but decreased Ca and Mg in leaf blades. Increasing the rates of CSP and KC1 hastened maturity and increased yields of cauliflower and broccoli in harvest sequences, whereas brussels sprouts were less responsive to CSP or KC1 at one harvest. High rates of CSP without KC1 reduced the yield of cauliflower compared to the lower rates. Increasing the rate of KC1 increased the incidence of hollow stem, a quality defect, in cauliflower and broccoli. Best production of uniform maturity and yield was obtained with a combination of the CSP at 336 kg·ha−1 and KC1 at 268 to 1072 kg·ha−1 per application in a long-term rotation.