Agricultural Research for Development in the Tropics: Caught between Energy Demands and Food Needs

摘要

The use of plant biomass for fuel is almost as old as mankind. However, a continuously growing population and the increasingly rapid exploitation of both fossil fuels and natural resources such as soil, water and biodiversity, have stimulated a debateof how to balance the needs and demands for food, feed, non-food raw materials and most recently energy in agricultural systems. Against the background of the current population growth, mankind faces the problem that the global system is closed and theavailable resources are finite. Energy is the only resource constantly supplied to the system from outside. All energy resources available on earth are in one way or the other transformations of one of the four following: a) solar energy - which can be exploited directly, is transformed into biomass by photosynthesis, and drives the global wind and water cyle, b) tidal force owing to gravitational pull between earth and moon, c) the earth's internal heat exploited as geothermic energy and d) nuclear energy. Of these, solar, tidal and geothermic energy are energy sources, which are not finite in time periods humans can still grasp. Based on data on fossil fuel reserves and consumption figures from the BP Statistical Review of Energy 2008 (BP, 2008), MACHANIK (2009) calculated the time when fossil fuel expires as 2208 at constant consumption, about 2082 at an energy consumption growth rate of 2.4% per annum, which was the growth rate from 2006 -2007, and at about 2057 at a more progressive growth of energy consumption of 5% per annum. There is therefore an urgent need to invest in research and development for the exploitation of renewable energy sources, on the other hand we face the situation, that for whatever reason it does not seem possible at themoment to tap fully fledged into the energy resources listed above.