Bioenergy and Agricultural Research for Development

Abstract

Converting agriculture to produce energy as well as food has become an important and well-funded global research goal as petroleum reserves fall and fuel prices rise. But the use of crop biomass-both grain and other plant parts-as a raw material for bioenergy production may compete with food and feed supplies and remove valuable plant residues that help sustain soil productivity and structure and avoid erosion. Agricultural research can mitigate these trade-offs by enhancing the biomass traits of dual-purpose food crops, developing new biomass crops for marginal lands where there is less competition with food crops, and developing sustainable livestock management systems that are less dependent on biomass residuals for feeds. Agronomists will need to define the minimum thresholds of crop residues for sustainable production in particular farming systems, especially in low-yield rainfed systems (that produce less than 5-6 metric tons of grain and straw per hectare), and to establish the level of additional residues that may be removed for other purposes, including biofuel production. Enhanced root growth offers another avenue for maintaining soil organic matter. Agricultural research can also help improve the energy efficiency of biomass crops, enhancing their value as renewable energy sources with low net carbon emissions. CROP-BREEDING OPTIONS TO ADDRESS BIOFUEL NEEDSAgricultural biofuels are currently based on the generation of ethanol from sucrose or starch derived from vegetative biomass or grain, on biodiesel from the more direct use of vegetable oils and animal fats. Ethanol has a high octane rating and can be blended in low proportions with gasoline for direct use in normal internal combustion engines.Further down the line, there is enormous potential to develop cellulose-based bioenergy systems. Plant biomass is an abundant and renewable source of hydrocarbons, and crops can generate more cellulose per hectare than sucrose or starch. Plant breeders should aim for high-density biomass production (for example, 15 tons per hectare in maize) rather than competing with crop residues or forest production for supplying materials to cellulosic biorefineries. Preliminary research shows significant genetic variation among maize and sorghum (brown midrib mutants) cultivars for cellulose and lignin content, suggesting that breeders can select for the increased quality of maize and sorghum stover for ethanol conversion. Breeders can also develop cultivars whose biomass lends itself readily to breakdown by fungi, improving ethanol production efficiency.Breeders can increase cellulose or hemicellulose production by making photosynthesis or nitrogen metabolism more efficient, but they must also select for enhanced water-and nutrient-use efficiency under resource-conserving systems that provide an overall energy savings and cut emissions of carbon dioxide and pollutants. Growing biofuel crops on lands not suitable for food production-for example, those affected by drought, salt, or temperature stresses-would substantially...

The EU–Africa Energy Partnership: Towards a mutually beneficial renewable transport energy alliance?

“…For example, apart from a few large farms owned by wealthy elites in Nigeria, farm sizes are becoming smaller as land is taken through the land-use decree of 1979 for urban development, roads and industry. At the same time, the oil, gas and mobile phone tower industry is growing rapidly owing to a favourable regulatory climate that captures scale economies (Ortiz et al, 2006). As a result, small-scale production, when contrasted against large-scale processing, is the direction that the future seems to hold for biofuels in sub-Saharan Africa.…”