Jatropha - As a Diesel substitude

The potential of Jatropha oil as a diesel substitute has already been recognized by Indian scientists, and several landowners in India have even started plantations of this tree. It is however still a very low yielding wild plant, yielding on an average about 200 to 500 kg seed per acre. In fact, this is true of most of the oil-bearing tree species in India. Most of them do not yield more than about 100 to 250 kg of oil per acre. The species of oil-bearing plants that are raised as field crops have been subjected to intense plant breeding input, and therefore yield at least four times as much oil. I agree that Jatropha is a plant that can survive under adverse conditions, but under poor agronomic conditions, the yield would be even lower. And there are many other species, that would give more money per unit area than Jatropha, even on waste land.
The oil plant Jatropha curcas (L) (Jatropha) or physic nut is a multipurpose and drought resistant large shrub or small tree. Although a native of tropical America, it now thrives throughout Africa and Asia. It grows in a number of climatic zones in tropical and sub-tropical regions of the world and can be grown in areas of low rainfall and problematical sites. Jatropha is easy to establish, grows relatively quickly and is hardy. Being drought tolerant, it can be used to reclaim eroded areas, be grown as a boundary fence or live hedge in the arid/semi-arid areas.
The wood and fruit of Jatropha can be used for numerous purposes including fuel. The seeds of Jatropha contains (. 50% by weight) viscous oil, which can be used for manufacture of candles and soap, in the cosmetics industry, for cooking and lighting by itself or as a diesel/paraffin substitute or extender. This latter use has important implications for meeting the demand for rural energy services and also exploring practical substitutes for fossil fuels to counter greenhouse gas accumulation in the atmosphere.
These characteristics along with its versatility make it of vital importance to developing countries subjected to decreasing tree cover and soil fertility because of increasing population and development pressures. Nearly half the world’s poorest people live on marginal lands with the number expected to increase from 500 million to 800 million by 2020. These areas are by definition isolated and fragile, with soils susceptible to erosion and subjected to environmental stresses of deforestation, prolonged droughts, and decreasing soil and ground water. Although southern Africa is rich in biodiversity and production potential, large areas are under semiarid and arid conditions with a moderate-to-high risk of drought. Plants species like Jatropha that can grow on lands not usually attractive for agriculture and supply raw material for industry, fuels for basic energy services and improve environment are therefore an obvious choice that needs to be assessed carefully and comprehensively.