ABSTRACT
There is growing pressure on agriculture for enhanced efficiency and productivity. This pressure stems from growing competition among agricultural, urban and environmental water users for more efficient use of increasingly scarce water resources. As the world population is increasing, so is the need for additional food and fibre. Moreover, the growing urban sector of society requires ever-increasing water supplies, fuelling ever-increasing conflict and competition for water. The world population is projected to cross the 7 billion mark by 2013, 8 billion by 2028, 9 billion by 2054 and 10 billion by 2183 (United Nations, 1999). The problem is multiplied when coupled with reduced water for agriculture, increased demand for food and fibre, and enhanced life-expectancy as the standard of living improves worldwide, while expecting higher production levels per unit area of land or unit volume of water.
