Increasing water productivity through deficit irrigation: evidence from the Indus plains of Pakistan

✍ Scribed by Asad Sarwar; Chris Perry

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 65 KB
• Volume: 51
• Category: Article
• ISSN: 1531-0353
• DOI: 10.1002/ird.39

✦ Synopsis

Abstract

Water shortage shifts attention from the traditional concept of crop yield—production per unit of land—to the productivity of water—production per unit of water. Whether this parameter is best increased through responsive, sophisticated irrigation scheduling or through predetermined schedules, providing limited water, has been a contentious issue for some years. This paper brings together modelling studies from Pakistan that address this issue, as well as raising the question of whether deficit irrigation threatens sustainability through the build‐up of salts in the soil profile.

It is shown that under conditions of plentiful water, highest productivity is achieved when irrigation is precisely scheduled to meet crop needs. However, when water is short its productivity is substantially increased (by almost 50%) by deficit irrigation. No salt problem occurs as long as amount of water applied through irrigation is sufficient to meet 80% of the total crop evapotranspiration. Under limited water conditions, the productivity achieved is little affected by setting predetermined irrigation schedules, allowing the operating agency to concentrate on reliability of service. Finally, it is also shown that the salt build‐up is independent of irrigation scheduling. Copyright © 2002 John Wiley & Sons, Ltd.