Supplemental irrigation in Iran: Increasing and stabilizing wheat yield in rainfed highlands

Abstract

Wheat is the most important food crop in Central and West Asia and North Africa. In Iran, although rainfed wheat occupies the majority of the cultivable lands, irrigated agriculture contributes most of the wheat production. While rainfed wheat occupied about 4 and 3 million ha in 1998 and 2000, respectively, yields in the two years ranged from 1094 to 701 kg/ha compared to 3423 and 2787 kg/ha for irrigated areas. However, studies have shown that rainfed wheat in Iran has a higher yield potential.

ICARDA initiated collaborative research with the Agricultural Research and Extension Organization (AREO) of Iran, which was implemented by the Dryland Agricultural Research Institute (DARI) in the highlands of northwestern Iran. The program focused on the sustainable management of scarce water resources for increased agricultural production in rainfed areas.

The research program aimed at increasing and stabilizing wheat rainfed production using supplemental irrigation (SI) where water resources are available. Specific objectives were to: • assess the impact of SI on the yield and water-use efficiency of wheat, • determine the optimal sowing period of rainfed wheat with SI, and • evaluate the response of some wheat cultivars to levels of nitrogen and SI.

Three field experiments were conducted starting in 1995 in various DARI-mandated environments and stations of the highlands to address the above issues. A summary of the results and conclusions of the research is presented in this report.