Economic and Environmental Evaluation of Different Irrigation Systems for Date Palm Farming System in the GCC Countries: Case of Oman

Abstract

In the frame of the ICARDA project “Development of sustainable date palm production systems in the GCC countries of the Arabian Peninsula”, researchers succeeded to introduce one promising technology (subsurface drip irrigation - SDI) in the date palm farming system in the Gulf region, defined as the poorest in the world in terms of water resources The objective to introduce this new technologies is to provide water application strategies that maximize yield and minimize water loss for a range of irrigation system designs and applied for date palm farmers in the GCC countries. In the light of these challenges, the main objective of this study is to evaluate the effect of the irrigation water volumes on the date palm productivity and water use efficiency under several conventional and improved irrigations systems. The examination of the performance of bubbler irrigation (BI) and SDI systems were conducted at Al Kamil and Al Wafi Agricultural Research Station – South Sharqiya, Sultanate of Oman. The performance of both systems was evaluated in terms of water use efficiency (WUE), economic performance, and yield of date palms (variety Khalas). Three intervention levels on SDI have been used: at the rate of 60% 40% and 20% of water requirement. Results of this experimental study showed that SDI under the three intervention/options uses water more efficient in comparison to BI. Indeed, a considerable quantity of water for about 3545.554, 5726.45, and 7565.473 m3/ha could be saved by using SDI at the rate of 20%, 40 and 60% of water requirements, respectively. Thus, the WUE indicator is for about 2.0, 2.7, and 4.7 kg/m3 , respectively. These figures are much higher when are compared to BI system where WUE is around 1.3 kgm-3. The economic evaluation and comparison between both systems suggest a considerable effect of the used irrigation method on the water cost, total return and net profit. Indeed, under BI system, the total return, total variable costs, water costs and net profit were 20211.36, 5857.81, 1224.29, and 13129.25 $ ha-1, respectively. From another hand, by using SDI at the rate of 60% of water requirements, we note a slight difference in net profit when using this irrigation system, which is about US$12825.02/ha. Economic findings suggest that using SDI method versus BI method have additional cost but is economical at the long term as the SDI found to sustain the date palm farming system in this region where arid conditions acts as natural constraints for expansive agriculture. Therefore, this sustainability of SDI in comparison to the BI could be reached if SDI system is well designed, maintained and used properly. Finally, findings suggest that SDI for date palms is an effective and practical method for irrigating date palms where, a noticeable volume of water could be saved due to the elimination of evaporation water compared to other irrigation systems including the BI. In addition, under the arid and semiarid climates conditions, where rainfall is minimal and the air temperature is high, this will result in high increase in evaporation rate from soil surface that result in salt accumulation in the top layer of the soil where active roots concentrate which in turn lead to yield reduction, the use of SDI system could eliminate the weed growth around the tree and prevent salt accumulation on the soil surface.