The optimal combination between row spacing and plant population can lead to the economic maximization of castor bean yield. This study aimed to analyze the production cost and profitability per hectare of two castor bean cultivars (IAC 2028 and FCA-PB), under eight different plant arrangements, in the summer of 2007/2008 and 2008/2009, in Botucatu, São Paulo State, Brazil. The best economic results were obtained when using narrower row spacing (0.45 m). The highest production cost occurred in 2007/2008, for the 70,000 plants ha-1 population, due to the use of a higher amount of seeds and fungicide applications, when compared to 2008/2009. The FCA-PB cultivar showed the highest profitability index (27.46%), with the combination of 0.45 m row spacing and 55,000 plants ha-1, in 2007/2008, with operational profit of US$ 655.47 ha-1.
Ricinus communis L.; economic analysis; plant population
