MORINGA BIOFUELS RESEARCH
The world, with emphasis on Africa, is faced with an increasing demand for energy and pressure for high potential agricultural land. Energy is a major economic factor in production, processing and transportation of agricultural crops which form the staple diet of a large proportion of our people. Therefore, fossil fuel oil reserves will deplete in time and carbon tax, imposed world wide on fossil fuels, will increase the cost of these fuels. The search for alternative fuels which promise energy conservation, efficiency, environmental protection and sustainable development is subsequently on.
Biofuel production from agricultural crops has increased more than threefold from 2000 to 2007 (FAO, 2008). It now covers nearly two per cent of the world's consumption of transport fuels and is continuing to grow. Reporting this, the UN Food and Agriculture Organisation (FAO), has called for an urgent review of both biofuels and farm subsidies to preserve food security, sustain the environment and protect poor farmers (FAO, 2008).
Land used for the production of biofuels and their by-products is projected by the International Energy Agency (IEA) to expand three-to-four fold at global level, depending on the policies pursued, over the next few decades, and even more rapidly in Europe and North America (IEA, 2007; FAO, 2008). In South Africa, areas of high potential land are reserved for food crops, as conventional biofuel crops pose a threat to food security. This has resulted in the motivation to explore alternative land for production of biofuel such as marginal soil along with food crops and for rehabilitated mines. Also, South Africa consists of sufficient amount of high to medium potential soil which is available for development. This land could be explored for production of biofuel as it lies between rural settlements and is fallow or not cultivated profitably. Conversely, a major climatic factor that could pose a threat to biofuels land expansion is South Africa’s water shortage.
The nature and extent of biofuel production impacting water, soils and greenhouse gas emissions is dependant on factors such as the land type selected, land-management practices, scale of production, type of feedstock, cultivation practices as well as product and by-product processing procedures. Many annual crops currently used for biofuel production have relatively high water requirements and nutrient demands as well as intensive pest and disease management practices for optimal yield production which could lead to excess nutrient run-off, ground water pollution and soil erosion. It is therefore imperative to investigate perennial crops that could produce sustainable yields (fuel/feed/fodder) under sub-optimal growing conditions with low input and management costs and then again secure food resources.
In South Africa a multi-purpose crop is needed which will benefit several industries. Moringa oleifera fits the criteria in all aspects. This “miracle tree” would benefit the rural communities of South Africa in which large scale plantations will provide plenty of employment opportunities and provide a sustainable income as Moringa can be consumed and sold as a food source and contribute to an improved quality of the rural water supply. Moringa seed will also benefit the biofuel industry as its oil has already been found to be suitable for the production of biodiesel (Rashid et al., 2008).
This tree is a suitable candidate as it grows worldwide in the tropics and sub-tropics, but will tolerate higher temperature extremes and can survive a light frost. It also tolerates a wide range of soil and rainfall conditions. Presence of a long taproot makes it resistant to periods of drought.
Moringa seedlings and small trees
Two Moringa orchards with different treatments were established at the experimental farm of the University of Pretoria in 2004. Since then field and glasshouse trials have been conducted to improve the cultivation practices of Moringa oleifera. The following research areas have been carried out on Moringa under the supervision of Prof Elsa S du Toit in the Department of Plant Production and Soil Science during the past five years:
- · Seed germination
- · Seedling growth
- · Vegetative propagation via cuttings
- · Temperature and growth regulator effects on growth and flowering
- · Water use at different irrigation levels
- · Plant growth performance under different planting densities and growing conditions
- · Phenological and physiological growth stages and water use
- · Measurements of tree water use
- · Sap flow measurements using the Heat Pulse Velocity system
Moringa orchard at the Hatfield Experimental Farm
Many studies have been carried out on the nutritional and medicinal values of Moringa oleifera for both humans and animals. Its importance in the purification of water has also been a subject of research for long. However, this tree species is still undomesticated, basic agronomic/horticultural properties are not thoroughly understood and the environmental effects on growth and seed development have not been investigated. As a result, the developmental seed morphology and anatomy of Moringa has not been researched, especially with regards to the accumulation of protein, carbohydrates and oil bodies. Electron/light microscopy in conjunction with staining techniques would give detailed information concerning the development of cell contents within the seed from embryo stage to the mature seed.
To guarantee the sustainability and feasibility of trees as bio-fuel crops, one needs to develop a suitable clone and continue optimizing production practices. Several research projects of above focused areas have been completed or are currently running at the experimental farm of University of Pretoria. No similar research work has been conducted at any other research institute in South Africa. Research results from other countries are also not always useful for South African conditions. Thus far there is a lack of knowledge on oil biosynthesis in Moringa seeds and how oil characteristics varies under certain growing conditions and the genes involved in this process. Considerable phenotypic variation relating to yield has however been observed in the Moringa oleifera plantation on the experimental farm of the University of Pretoria. Limited information is available regarding the genetic diversity of Moringa oleifera, and to date only a few studies on the genetic diversity were reported. Studies relied on AFLP to detect genetic variation and were focused on the identification of germplasm origin and conservation.
Also, seed longevity and oil durability over time is in question due to a lack of knowledge on optimal post- harvest practices. Specifically, the effects of the storage conditions on the seed viability, oil content and oil quality have not yet been investigated. Current research projects hope to provide standards for the optimum seed storage conditions, which is of vital importance for the development and commercialization of this potential oilseed crop.