|Irrigation-Induced Salinity - A Growing Problem for Development and the Environment (World Bank, 1993)|
Irrigation has contributed significantly growth in agricultural production in many developing countries during the last century. However, irrigation-induced salinity is an increasing problem in several of these countries, threatening the productivity of agricultural lands. FAO (1990) reports that about 20 to 30 million hectares are severely affected by salinity and an additional 60 to 80 million hectares are affected to some extent. In some regions, the impact of salinity is felt across international borders. This report reviews the extent of the problem in various countries and examines the technical, economic, social, and institutional factors contributing to the onset of irrigation-induced salinity. It subsequently reviews the array of strategies that can be pursued to ameliorate the problem. The report finds that poor water management (e.g. over application by farmers, excessive seepage throughout the irrigation system, absence of or inadequacy of drainage infrastructures) is the primary cause of irrigation-induced salinity. Although salinity is a technical problem, it is also the product of several other factors. Distortive government policies contribute to inefficient water use, and poor project planning and implementation leads to the rapid deterioration of infrastructures. In some cases, the lack of or weak understanding of the problem or the lack of or weak commitment to environmental protection by public officials and policy-makers contributed to the spreading problem of salinity.
The battle against salinity has to be launched in three fronts. Governments have to commit to a policy of sound water management and to the fostering of an economic environment that promotes efficient water resource use, e.g. appropriate pricing of irrigation water. At the same time, country agricultural strategies should incorporate measures to promote the adoption of environmentally sound production methods, particularly efficient water-use among farmers. Greater effort also has to be directed towards the analysis of the environmental impact of projects that involve water resource use and development to ensure that only economically and environmentally sound projects are undertaken.