Low Cost Irrigation: Experience from the Past

Artificial drainage is usually an essential component of irrigated farming in low rainfall areas, but it is expensive. This article looks at a system without artificial drainage that was used in ancient Mesopotamia for thousands of years. Its three elements were a two-year rotation of winter cereals with a fallow of deep-rooted leguminous weeds, mixed farming with animals grazing the fallow, and a thorough wetting of the soil before the first ploughing. Although there was a high water table the system minimized the threat of salinity and provided nutrients for the cereal crops. Eventually the soils became saline, the possible causes of which are discussed. The principles of the system may have applications to the present day where large capital investment is not appropriate.