Análise técnica e econômica da adubação mineral e orgânica sob o cultivo da mamona e do pinhão manso.

Abstract

The oil extracted from seeds of the castor bean (Ricinus communis L.) and Jatropha (Jatropha curcas L.) has many industrial applications. However, today has given emphasis to its use in biodiesel production that covers these oilseed of great economic importance and environmental. Thus, two experiments were conducted during the years 2007, 2008 and 2009 with the aim of evaluating the effects of different sources of fertilizers on vegetative growth, yield and quality of the castor beans (Ricinus communis L.) and physic nut (Jatropha curcas L.) in the field and upland in Jacaré farm in the municipality of Remigio-PB. The experiments were conducted in a randomized block design with three replications and five treatments (nutrient sources), they were: absolute control (F1), compost alone (F2), compost enriched with post rock (F3) manuring (F4) and bovine manure (F5). It was found in the first experiment (Ricinus communis), which in both production cycles, the plants fertilized with organic sources had the highest average growth and production. In the second cycle, the castor pruned showed low survival rate and decreased productivity. In the second experiment (Jatropha curcas), no significant influence of the sources of fertilizer on the growth variables in almost all periods. However, with the use of renewable organic plants have issued the highest number of inflorescences and promoted the highest yield. In both experiments, the highest oil yields were obtained to composting plants with the source F2. But regardless of the source of fertilizer used, the oil content in castor seeds of jatropha surpassed. Under conditions in which the experiment was conducted, regardless of source of fertilizer used and the year of cultivation, exploitation of the Jatropha curcas castor proved to be economically unfeasible.