We are using high quality oil seeds both for growing plants and also for extraction of oils such as Jatropha oil to produce Biodiesel. After extracting oil from the seeds the remaining matter that is left behind as byproduct is oil cake. These oil cakes such as Jatropha oil, Pongamia oil and castor oil cakes are rich in nutrients and can be used for a wide variety of applications. Jatropha oil cakes contains all the micro and macro nutrients like Nitrogen, Phosphorus, Potassium, Calcium, Magnesium, Zinc, Iron, Copper, Manganese, Boron and Sulfur thus has high nutritive value. In this way, the cake is an excellent medium to reduce the dependence on chemical fertilizers and can be used as organic manure. The cake can also be used for biogas before composting and both these processes will improve the domestic energy status and nutrient availability as fertilizer to the crops. It has both insecticidal and molluscicidal properties.
Castor oil cakes have many uses like its use as an organic fertilizer when supplemented with ammonium sulfate can be used for rice, banana, tomato, potato, tobacco, wheat/barley, maize, jute, sugarcane crops and when it is mixed with urea in equal amounts can be used as a nematicide.
Pongamia seeds have about 30-35% oil and up to 27-28% oil can be expelled by crusher and most of the physical and chemical properties of the oil is almost similar to those of the diesel. Oil is also used as a lubricant, water paint binder, pesticide and in soap making and tanning industries. It is also a drought resistant plant. Oil cakes are good organic fertilizer and bears nitrogen 4%, phosphorous 1% and potassium 1%, which is better than vermicompost. Root nodules formation due to Rhizobium strains in nursery and in fields is common by which nitrogen is replenished in soil. Dense network of lateral roots of Pongamia control soil erosion. Leaves also act as good manure.
