ABSTRACT
Food production statistics indicate that approximately 30% of the world’s food supply is produced by irrigated agriculture and that this percentage will increase in future. As such, irrigated agriculture has an important role to play in meeting the world’s future food demand. Irrigated agriculture is practiced in humid areas to supplement rainfall, particularly during droughts, and in arid and semi-arid areas of the world as the sole water supply during crop production. Recent statistics compiled by the International Commission on Irrigation and Drainage (ICID) for 97 member countries of the Commission show there are approximately 271.1 Mha of irrigated land.[1]
However, there are no statistics to indicate what percentage of this irrigated area requires drainage. The most recent statistics on irrigation methods show that about 6% (15 Mha) of this irrigated area is irrigated by either sprinkler or micro-irrigation implying that the remainder of the area is irrigated with some other method, most probably using surface irrigation techniques. This is significant, since surface irrigation methods used on 94% of the world’s irrigated area are generally considered to be less efficient than sprinkler or micro-irrigation. Areas where inefficient irrigation takes place are more likely to require artificial drainage to sustain crop production.
