Oil Crops

The intrinsic characteristics of the oil crops which can potentially be grown in a given area are the main factor for the choice of the best suited species for that area. The oil palms (Elaeis spp.) comprise two species of the Arecaceae family, grown in commercial plantations for the production of edible oil since a long time; more recently, they are being dedicated to biodiesel production. Plants are monoecious, their fruits being drupes; they seldom are more than 8-10 m high in crop fields. The palm oil cycle starts with a long establishment phase, without any fruit yield for a few years. A modern palm plantation can yield more than 20 t/ha of fruits, which means almost 5 t of palm oil, plus additional kernel oil (around 60% of palm oil yield). Other palm species for oil production include the Macaúba or macaw palm (Acrocomia aculeata (Jacq.) Lodd. ex Mart.), which is raising a certain interest in Brazil, and the coconut palm (Cocos nucifera L.), which is grown throughout the tropics for food and industrial uses. Jatropha (Jatropha curcas L.) is a perennial, semi-evergreen shrub with glabrous, ascending branches, growing in tropical and subtropical regions, tolerating drought. The plant is poisonous, since it contains a toxin; the seed contains 27-40% of non-edible oil, which can be extracted to be directly used or further processed into biodiesel. Castorbean (Ricinus communis L.) is a fast-growing, suckering perennial shrub which can reach the size of a small tree. In the tropics, castorbean is perennial, whereas in temperate regions it cannot survive winter temperatures and is grown as an annual crop. The seed contains 40-60% of oil which is rich in unsaturated fatty acids. Sunflower (Helianthus annuus L.) is an annual herbaceous oil seed species. The plant is cropped in many warm regions of the world. It grows in the warm season, but is quite tolerant to low temperatures. At maturity, the dry fruit (achene) contains 40-50% oil. After oil pressing, the residual meal is rich in protein (about 30%), having a high value as animal feed. Soybean (Glycine max (L.) Merryl) is a leguminous species native to East Asia. Soybean is a short-day plant. Successful growth requires warm weather: optimum conditions are temperatures of 20 to 30 °C. The seed mainly contains protein (40%) and oil (20%) on a dry weight basis. The seed is normally processed into a vegetable oil, and in a defatted soybean meal which is a primary source of protein for animal nutrition. Oilseed rape (Brassica napus L. var. oleifera d.C.), is a yellow flowering member of the Brassicaceae family. Oilseed rape is typical of temperate-cold climate; in Central Europe and in the U.S. it is normally sown in the early autumn or in the early spring; the crop cycle ends in June or July. The seed is globose, small and contains about 40-45% of oil (dry weight basis) and 20-25% of protein.