Response of castor bean cultivar BRS 188 Paraguaçu to application of nitrogen, phosphorus and potassium

Abstract

The present study was carried out aiming to evaluate the effects of nitrogen, phosphorus and potassium on the growth and production of seeds of castor bean (Ricinus communis L.). Three experiments were conducted in a greenhouse, in Campina Grande, Paraiba State, Brazil. The experimental design was a completely randomized with three replications and five treatments, with reference dose of 40:90:60 kg ha^-1 of N:P₂O₅:K₂O, respectively.  A single castor bean plant, cultivar BRS 188 - Paraguaçu, was cultivated in each experimental unit. The treatments of the first, second and third experiment consisted of application of five N levels (40 to 200 kg ha^-1), five P₂O₅ levels (30 to 150 kg ha^-1) and five K₂O levels (30 to 150 kg ha^-1). Plant height, stem diameter, number and length of leaves were measured at 20, 40, 60, 80, 100, 120 and 140 days after planting (DAP). The unbalanced fertilization affected the development and seed production of castor bean, and the best response of the plants was observed at levels of 200 kg ha^-1 de N; 120 kg ha^-1 de P₂O₅ and 150 kg ha^-1 de K₂O.