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

Abstract

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