Improving Quantity and Quality of Castor Bean Oil for Biofuel Growing under Severe Conditions in Egypt

Castor bean (Ricinus communis) has emerged as a biofuel crop with potential for its production in marginal land with application of treated sewage water. Some projects in different scales are established to produce castor bean seeds, but additional research is needed to develop the optimal management programs, including the nutrients which help plants to resist the severe conditions such as marginal (bad) soil and the irrigation by treated waste water, reaching to the effect on the produced oil. A field experiment was conducted in El-Gabal El-Asfer Farm, Cairo, Egypt, during 2012 and 2013 growing seasons to evaluate the effect of two rates of foliar K-Amino fertilizer on the productivity as well as the quality characteristics of castor bean oil irrigated by three water regimes of secondary treated sewage water. Results indicated that the maximum seed yield (1026.68 kg fed.−1, one feddan equals 4200 m2) was obtained from spraying plants by 100% of K-amino rate under the irrigation with 75% of the calculated Etc. Castor oil properties indicate low pour points which make this biofuel a good alternative in winter conditions or in the low temperature. The produced oil under 75% of Etc (recommended evapotranspiration) water regime showed good flow properties. It indicates that castor oil biofuel also could be used as petroleum diesel additive improving both environmental and flow behaviour of the mineral fuel. Generally, producing castor bean oil by spraying of K-amino fertilizer under the irrigation of 75% and/or 100% of Etc water regime is more appropriate to produce biofuel.