NPK fertilization and sowing time for castor plant. I - production and yield components

The objective of this work, was to investigate the production and yield components of castor bean cultivars submitted to mineral fertilizer, sowing times and locations. The experiments were conducted at the CCA/UFC in Pentecoste and the CENTEC in Limoeiro do Norte, Ceara Brazil. Were used four criteria for fertilizer recommendation of mineral fertilizer 0-0-0; 40-25-15; 80-50-30 and 120-75-45 kg ha(-1) of N-P2O5-K2O, two varieties of castor bean (BRS Nordestina and Mirante 10); two sowing times (early sowing and dry sowing) and two locations (Pentecoste and Limoeiro do Norte). The experimental design was arranged in a randomized block, factorial 4x2(3), with four replications. In general, the NPK fertilizer provided varied results, largely due to good soil fertility in the two localities studied, and the water availability, was the factor that caused the greatest effect on productivity of cultivars. The mass of racemes increased in plants fertilized with NPK and water supplementation in early sowing, helping to increase the mass of seed and grain yield and oil. The largest increases were observed in the variables studied in the town of Pentecoste, regardless of cultivars and sowing systems evaluated, due to the longer time of soil moisture from inadequate drainage.