ABSTRACT
Abstract The value of water conservation to irrigated agriculture can be linked to the capital investment required for improved irrigation water management, or costs associated with loss in yield due to smaller annual water applications. In this study, we consider the value of water attributable to loss in alfalfa yield in the Imperial Valley, California resulting from reducing the frequency of irrigation during peak evapotranspiration demand periods, and use of a cut-off time border irrigation method that eliminates tail-water runoff. Reducing the number of annual water applications by two, four and seven times as compared to an optimally watered control resulted in yield losses of 1530, 3840 and 5230 kg/ha, or an annual water saving of 53, 362, and 627 mm/ha, respectively. At a market value of $0.11/kg ($ 100/ton), the average value of each increment of water saved for the progressively fewer annual irrigations was $3308, $1194 and $940 /ha-m, respectively. Following reduced irrigation treatments, salt leaching was required to restore satisfactory soil conditions. The cut-off time irrigation method resulted in similar annual water savings (108 mm/ha), yield losses (1431 kg/ha) and slightly smaller water values ($538 /ha-m) but incurred only limited salinization at the low end of the fields after one year. Keywords: Water conservation, soil salinity clay soils, irrigation management, crop yield
Water: Economics, Management and Demand. Edited by Melvyn Kay, Tom Franks and Laurence Smith. Published in 1997 by E & FN Spon. ISBN 0 419 21840 8.
