The Jatropha curcas as a substitute for Ricinus communis in biodiesel production in the semi-arid region of Brazil

In Brazil, public policies have been promoting the use of renewable energies, with a particular emphasis on biofuels, as well as research for the replacement of fossil fuels, among which biodiesel stands out. The primary species used for biodiesel production is castor bean (Ricinus communis), widely disseminated in the semi-arid region due to its resistance to long dry periods and its requirement for highly fertile soils. However, another crop is emerging in this process: the Jatropha curcas L. This species, native to Brazil and belonging to the Euphorbiaceae family, the same as castor bean, requires strong sunlight and is also highly drought-resistant. Additionally, it can tolerate increased rainfall and soils with poor chemical characteristics. This study presents the results of three years of cultivation of Jatropha curcas and castor bean at the Rio Seco Experimental Station (Amélia Rodrigues, Bahia, Brazil), a region located on the marginal zone of the semi-arid area, which is also hot but has a higher rainfall index and chemically poor soils, comparing their productivity and respective edaphoclimatic aptitudes. It was observed that castor bean has a significant restriction concerning humidity, as its cultivation and development showed low production, frequently associated with fungal action due to humidity and low yield due to the type of soil, resulting in non-viability for biofuel production in this region. However, Jatropha curcas showed better results, indicating greater adaptability. Nevertheless, Jatropha curcas is still a little-known plant, both in its productive cycle and productivity, requiring further studies to efficiently monitor its phenological cycle and the duration of its productive cycle.