ENERGY IN IRRIGATION IN DEVELOPING COUNTRIES : AN ANALYSIS OF ENERGY FACTORS TO BE INCLUDED IN A NATIONAL FOOD POLICY

The authors find that developing groundwater supplies entails twice the energy costs of developing surface water supplies, and that the latter can be more efficiently manufactured, installed, and operated in developing countries. In determining the amount of energy needed to manufacture, install, and operate various irrigation systems, it is found that sprinkler and trickler systems are competitive only when pumping lifts are very high (100 meters). Discussion of renewable energy sources covers biomass systems such as direct combustion and gasification, as well as solar and wind sources. Currently, agricultural production of biomass fuel is a problem due to the fuel/food conflict in developing countries. The potential of solar power, e.g., photovoltaic cells, is also discussed. Unfortunately, solar costs remain high. Finally, wind energy was found to be technically more suitable for developing countries than biomass and solar sources. The impact of energy alternatives on the food production effectiveness of irrigation systems is also assessed, with stress laid on the importance of providing water at crop-critical times -- a point of essential importance for systems such as windmills. Energy is best saved by eliminating water losses, although upgrading poorly designed irrigation systems can also save water and energy supplies. Recommendations, in their order of priority, are: reduce water losses in watercourses and water distribution systems; improve on-farm irrigation practices; maintain irrigation pumps; water crops only in accordance with their needs; and use surface water sources when available. It is also recommended that research concentrate on improving on-farm water management systems and that governments realistically assess their irrigation systems" energy needs in light of food needs. Tables, graphs, appendices, and a 83-item bibliography (1954-80) are provided.