The role of limited irrigation and advanced management on improving water productivity of rainfed wheat at semi-cold region of upper Karkheh River Basin, Iran
Authors:
In order to evaluate the role of a limited irrigation (LI) and agronomic management on
improving rain water productivity, a field study was conducted during 2005-08 winter cropping
seasons of wheat at multiple farms across benchmark watershed of Honam (Lorestan Province) in
the upper Karkheh River Basin (KRB), Iran. limited irrigation consist of four treatments; single
irrigation (SI) at planting time, single irrigation at spring time, two times irrigation (planting time and
spring) and Rainfed, and so agronomic management practices consist of two treatments: traditional
and advanced management (TM and AM), were evaluated. The results of this study showed that
under rainfed conditions, wheat grain yield of AM (2321 kg ha-1) increased by 34.5% as compared to
TM (1726 kg ha-1). At Honam site, the optimum program was obtained by a combination of advanced
agronomic management package with SI options (irrigation at planting time/spring time), in which the
maximum water productivity and net benefit were obtained. The advanced agronomic management
(AM) had better performance as compared to traditional management. At rainfed conditions, WP of
traditional management (0.35 kg m-3) increased by 28.6% as compared to advanced management
(0.45 kg m-3). The results of this study showed that a single irrigation application at sowing or spring
time (during heading to flowering stage) increased total water productivity (TWP) of wheat to a range
of 0.57 to 0.63 kg m-3 during average three seasons. The average irrigation water productivity (IWP)
of wheat reached a range of 2.15-3.26 kg m-3 by using single irrigation at sowing or spring time. Low
WP (and yield) in farmers’ practices of rainfed conditions, were mainly due to suboptimal agronomic
management practices. These preliminary results confirm the potential of single irrigation and
early/normal planting as an effective method to enhance productivity.