Silvicultural production systems and nutrient requirements of Jatropha curcas in prospect and retrospect
silvicultural production systems and nutrient requirements of Jatropha curcas which can be summarized as below: • What are the best management techniques (planting practices, spacing, etc.) to promote the optimum growth of Jatropha to optimize for instance nut production? • What types of edaphic factors, climatic conditions provide best for Jatropha curcas, both from the perspective of fruit and biomass? What is the ideal rotation age for nuts and the plant? What varieties, including non-toxic varieties perform better in southern Africa? • How can Jatropha curcas plantations by themselves or in agro-forestry combinations (climatic conditions and management practices) alleviate problems of devegetation and soil erosion and improve, the environment. • Available biological control/IPM techniques to control of pests and diseases of Jatropha. 1.2 Jatropha curcas as an Energy Source 1.2.1 Oil from Jatropha curcas Jatropha oil is an important product from the plant for meeting the cooking and lighting needs of the rural population, boiler fuel for industrial purposes or as a viable substitute for diesel. Substitution of firewood by plant oil for household cooking in rural areas will not only alleviate the problems of deforestation but also improve the health of rural women who are subjected to the indoor smoke pollution from cooking by inefficient fuel and stoves in poorly ventilated space. Jatropha oil performs very satisfactorily when burnt using a conventional (paraffin) wick after some simple design changes in the physical configuration of the lamp. About one-third of the energy in the fruit of Jatropha can be extracted as an oil that has a similar energy value to diesel fuel. Jatropha oil can be used directly in diesel engines added to diesel fuel as an extender or trans-esterised to a bio-diesel fuel. In theory, a diesel substitute can be produced from locally grown Jatropha plants, thus providing these areas with the possibility of becoming self sufficient in fuel for motive power. There are technical problems to using straight Jatropha oil in diesel engines that have yet to be completely overcome. Moreover, the cost of producing Jatropha oil as a diesel substitute is currently higher than the cost of diesel itself that is either subsidized or not priced at "full cost" because of misconceived and distorted national energy policies. Nevertheless the environmental benefits of substituting plant oils for diesel provides for make highly desirable goals. In 1995, the Rockefeller Foundation (RF) and the German Government’s Technical Assistance Programme (GTZ) joined together to evaluate the use of plant oil as a renewable fuel source for rural development in three of the countries -- Brazil, Nepal and Zimbabwe. Since species whose cultivation would not displace other agricultural crops nor compete for land with greater opportunity for other applications were being considered, Jatropha curcas emerged as a prime plant for investigation. This workshop builds on the earlier work of this initiative and examines rural development and generation of employment in southern Africa to determine the issues, need and prospects for further research and development. The workshop will therefore discuss various issues including: • Status of ongoing and potential research focusing on the applicability of Jatropha oil to meet the cooking and lighting needs of rural households and its competitiveness in substituting diesel in various stationary and mobile applications • Economic feasibility of Jatropha oil in meeting the energy services needs; • Available technology and products to meet the above mentioned needs and status of technological research; • Role of the private sector and government policies in commercialization of Jatropha curcas products. 1.2.2. Other products of Jatropha curcas Although ability to control land degradation and oil production are most important environmental uses of Jatropha, its products provide numerous other benefits that would additionally improve the living conditions of the rural people and offer greater income opportunities through enhanced rural employment. For instance, the Jatropha oil can be used for soap production and cosmetics production in rural areas and all parts of the plant have traditional medicinal uses (both human and veterinary purposes) that are being scientifically investigated. The oil is a strong purgative, widely used as an antiseptic for cough, skin diseases, and as a pain reliever from rheumatism. Jatropha latex can heal wounds and also has anti-microbial properties. Jatropha oil has been used commercially as a raw material for soap manufacture for decades, both by large and small industrial producers. Soap from Jatropha oil is being made by small informal industries in rural areas in both Zimbabwe and Mali. A large manufacturer is interested in using Jatropha oil to substitute tallow in commercial soap making. The monthly requirement of this industry alone is 2,000 liters of oil. To supply this demand would require between 18,000-22,000 ha of Jatropha plantation or 30,000-40,000 km. Of Jatropha hedges or a combination of the two. Currently tallow fetches higher price than diesel in Zimbabwe. What are the possibilities of using commercial interest as above to create a capacity for Jatropha oil to address issues of rural energy equity and employment generation? The oil cake cannot be directly used as animal feed because of its toxicity, but it is valuable as a fertilizer having a nitrogen content comparable to chicken manure and castorbean seed cake. The toxicity of the seeds is because of curcin (a toxic protein) and diterpene esters. Apparently seeds of Mexican origin have less toxic content and with proper processing they can be eaten. Although there are laboratory studies indicating detoxification, its feasibility and profitability on a large scale is yet to be investigated.