Efficient soil water use: The key to sustainable crop production in dry areas of West Asia and North and Sub-Saharan Africa: proceedings of the 1998 (Niger) and 1999 (Jordan) Workshops of the Optimizing Soil Water Use (OSWU) Consortium

Abstract

Within the next 30 years, the world's population will rise to 7-8 billion, bringing in its wake an urgent need to double the existing levels of world food production. Agenda 21 of the 1992 United Nations Rio Earth Summit makes a specific call for an improved knowledge base for sustainable production, coupled with the ability to make better long-term predictions and build extra-scientific capacity with clear research priorities at the national, regional, and global levels. Sustainable agriculture has, therefore, become a key component of production systems all over the world, given the evolution of certain important factors: increasing concern about the degradation of the natural resource base; low commodity prices leading to low-input systems; and an increasing concern about food quality and improving the welfare of the rural life. Sustainable agricultural systems are designed to make optimal use of existing natural resources to produce food and feed which are both nutritious and safe. International studies estimate that nearly a quarter of the world's agricultural, pasture, and forest land has been degraded in the last SO years. Soil quality, fertility, and water supplies need to be managed effectively and conserved through the husbandry of natural resources and land-improving investments. Effective soil, water, and nutrient management (SWNM) require action not only at the farm level, but also at the community, watershed, regional, and national levels.

Within the framework of the CGIAR System-wide Initiative on Soil, Water, and Nutrient Management (SWNM), four consortia are adopting this approach: managing soil erosion, acid soils, soil nutrients, and soil water. The Optimizing Soil Water Use (OSWU) Consortium is convened by ICARDA and ICRISAT, with the Institut d'~conomie Rurale (IER) of Mali as their National Agricultural Research System (NARS) partner. Given the ever-growing populations of the world's arid and semi-arid regions, the erratic and variable rainfall in these regions, and the limited possibilities of increasing the area cultivated, the agricultural priority across all dry area farming systems in Sub-Saharan Africa (SSA), and West Asia and North Africa (WANA) are to increase the biological and economic yield per unit of water.

Actual water-use efficiency in current farming systems in the drought-prone countries of WANA and SSA is often low. Therefore, the challenge is to devise effective and practicable solutions for resource-poor farmers in the context of local biophysical and socioeconomic constraints and of the uncertainties of applying the classical principles of soil-crop-water relations in rainfed and marginal environments. It is only by fostering technologies integrating both improved soil water use and nutrient availability to crops, that production can be increased in a sustainable way, and the risk of crop failure minimized for farmers in the dry areas of SSA and WANA. Within the above-mentioned constraints in both ecoregions, the long-term goal of OSWU is to attain sustainable and profitable agricultural production in dry areas based upon the optimal use of the available water