Planting time and irrigation management for castor plant. I - effect on yield components

Abstract

The early planting of castor plant associated with irrigation, especially under conditions of high vapor pressure deficit can further increase productivity. The purpose of this study was to investigate the effect of several different sowing times and supplemental irrigation on growth and yield of castor oil plant. The experiment was carried out at the experimental farm of the Universidade Federal do Ceará, at Pentecoste, Ceará, Brazil. Standard cultural practices of soil preparation and fertilization were used. Seeds of castor bean cv. BRS Nordestina were planted with spacing of 1.5 m x 1.0 m, with one plant per hill. The experimental design was arranged in a randomized block with eight treatments and four replications. Treatments were composed of four sowing times and different irrigation managements. Seed yield was highest in plants sowed in January. Water supply was more efficient when applied at the beginning than at the end of the plant life cycle. The oil yield was closed related to the seed yield. The number of internodes was positively correlated with the earliness of the castor bean and the oil yield was closed related to the seed yield. The secondary racemes had the highest contribution for the total seed yield.