ReseaRch PaPeR Journal of Agricultural and Marine Sciences Vol. 22 (1): 87–91 DOI: 10.24200/jams.vol22iss1pp87-91 Reveived 15 Aug. 2016 Accepted 19 Dec. 2016 Increasing water productivity enhances water saving for date palm cultivation in Oman Y. A. Al-Mulla1* and H. M. Al-Gheilani2 *1 Yasseen Al-Mulla ( ) 1Department of Soils Water and Agricul- tural Engineering, P.O. Box 34, Al-Khod 123, College of Agricultural and Marine Sciences, Sultan Qaboos University, Sultanate of Oman. Email:yalmula@squ.edu.om. 2Ministry of Agriculture and Fisheries, P.O. Box 467, Al-Khwair 113, Muscat, Sultanate of Oman Introduction One total area of the Sultanate of Oman is 30.95 million hectares, where around 4.8%, i.e. 1.5 million hectares, of this area is considered suitable for growing crops. Only 4.4% of these available arable lands, i.e. 0.21% of the total country area, are currently cultivated covering an area of 65967 hectares (World Bank, 2015; MAF, 2014). There are 7.6 million date palm trees currently plant- ed in the farms in Oman covering an area of 23241 hect- ares or 35% of total agricultural area in the Sultanate in addition to 0.9 million palm trees planted in homes or for landscaping in public parks and beside the roads. Hence, date palm is considered as plant number one in the country. The total production of date palm trees in 2014 was 317 million kg of dates. Around 54% of these dates (Fig. 1) were consumed by people locally whereas 24% and 19%of the dates were used for industry and as forage for animals, respectively, and 3% of them were ex- ported outside the country (MAF, 2015). The total production of date palm trees and the pro- duction per tree in the Sultanate from 1998 to 2014 are زايدة إنتاجية املياه يعزز من توفري املياه من زراعة أشجار النخيل يف سلطنة عمان ياسني بن أمحد املال و محد الغيالين Abstract. The total amount of water consumption needed to irrigate the cultivated lands in the Sultanate Oman is 1487 Mm3. There are 7.6 million date palm trees currently planted in the farms in Oman covering an area of 23241 hectares or 35% of total agricultural area in the Sultanate in addition to 0.9 million palm trees planted in homes or for landscaping in public parks and beside the roads. Hence, among all cultivated crops in Oman, date palms are the major water consuming plants. They consume 558 Mm3 that is 38% of total irrigation water and 31% of groundwater recharge that suffers an annual water deficit estimated at 316 Mm3. These findings framed the main objectives of this study: (1) to describe the current status of date palm tree cultivation in the Sultanate; (2) to suggest solutions to reduce high consumption of water while improve dates production; and (3) to explore how irrigation water can be saved through increasing water productivity through alternative date palm cultivation and irrigation practices. The water saving rec- ommendation in this study was based on the collected from different sources in addition to the investigation on the water loss during irrigation practices. We found that it is possible to save a total of 396 Mm3 of irrigation water by for instance reducing the cultivation of low quality/value date palm varieties and switching to modern over traditional irrigation systems. It is also important to determine the quality and value of the date palm cultivars to be planted in the proposed reduced area which will then contribute to an increased financial return for the farmers and thus to the country through increasing the water productivity by 64% of these new plots. Keywords: Water productivity; irrigation water; economical return; date palm trees; Oman. امللخــص: امجــايل كميــة امليــاه الالزمــة لــري األراضــي املزروعــة يف ســلطنة عمــان هــو 1487 مليــون مــر مكعــب. ويبلــغ عــدد أشــجار النخليــل املوزرعــة يف عمــان حاليــا 7.6 مليــون شــجرة خنيــل تغطــي مســاحة قدرهــا 23241 هكتــار أي 35٪ مــن إمجــايل املســاحة الزراعيــة يف الســلطنة باإلضافــة إىل 0.9 مليــون شــجرة خنيــل مزروعــة يف البيــوت و احلدائــق العامــة وجبــوار الطــرق . وبالتــايل، مــن بــني مجيــع احملاصيــل املزروعــة يف عمــان، تعتــر النخيــل هــي النباتــات األكثــر اســتهالكا للميــاه. إهنــا تســتهلك 558 مليــون مــر مكعــب مــن امليــاه أي 38٪ مــن إمجــايل ميــاه الــري و 31٪ مــن امليــاه اجلوفيــة الــي تعــاين مــن عجــز مائــي ســنوي يقــدر بـــ 316 مليــون مــر مكعب.علــى ضــوء هــذه الــدالالت مت تأطــر األهــداف الرئيســية هلــذه الدراســة: )1( لوصــف الوضــع الراهــن لزراعــة شــجرة النخيــل يف الســلطنة. )2( لوضــع اقراحــات مــن شــأهنا تســاهم يف اجيــاد احللــول للحــد مــن اســتهالك الكميــات الكبــرة مــن امليــاه مــع حتســني إنتاجيــة التمــور. و )3( إلستكشــاف آليــة متكــن مــن ترشــيد ميــاه الــري مــن خــالل زيــادة إنتاجيــة امليــاه عــن طريــق اجيــاد بدائــل أخــرى ملمارســات زراعــة النخيــل وعمليــات ري هــذه األشــجار. اســتندت هــذه الدراســة علــى بيانــات مت مجعهــا مــن مصــادر خمتلفــة باإلضافــة إىل اســتقصاءات حــول فقــدان امليــاه مــن خــالل ممارســات الــري املختلفــة. لقــد وجدنــا أنــه مــن املمكــن توفــر مــا جمموعــه 396 مليــون مــر مكعــب مــن ميــاه الــري مــن خــالل علــى ســبيل املثــال احلــد مــن زراعــة أصنــاف النخيــل املنخفضــة اجلــودة / القيمــة والتحــول إىل أنظمــة الــري احلديثــة. ومــن املهــم أيضــا حتديــد األصنــاف اجليــدة مــن النخيــل ذات القيمــة العاليــة لزراعتهــا يف املســاحات املقرحــة والــذي سيســاهم يف زيــادة العائــد االقتصــادي ألصحــاب املــزارع والدولــة بشــكل عــام مــن خــالل زيــادة إنتاجيــة امليــاه بنســبة 64٪ مــن امليــاه املســتخدمة لــري هــذه النباتــات. الكلمات املفتاحيه: :إنتاجية املياه، أشجار النخيل، مياه الري، العائد االقتصادي، عمان 88 SQU Journal of Agricultural and Marine Sciences, 2015, Volume 19, Issue 1 Increasing water productivity enhances water saving for date palm cultivation presented in (Fig. 2) (Kamoonpuri, 2014; MAF, 2014, MAF; 2010, MAF, 2007; MAF, 2004a; MAF, 1999) whereas (Table 1) presents the annual production of top cultivars of date palm trees. These cultivars produce 44% of total dates production in Oman (MAF, 2010, 2013, 2015). From this table, it can be noticed that the five most productive date palm trees in the Sultanate are “Neghal”, “Khesab”, “Fard”, “Khalas”, and “Um silla”, with production percentages of 12%, 9.8%, 7.6%, 7.3%, and 7.1% of total dates production. Each hectare planted with date palm trees produce an average of 6075 kg of dates with an average income of 1065 OMR. The water recharge in the Sultanate of Oman is es- timated at 1267 million m3 per year. Additional water recharge comes from treated wastewater with amount of 42 million m3 and from desalination with an amount of 196 million m3. From the available water resources 1487 million m3 is used for agricultural purposes, whereas, 158 million m3 is used for domestic, commercial, mu- nicipal, and industrial purposes (Al Shibli, 2014, Al- Jabri, 2013, FAO, 2009, Al-Hattaly, 2005 and McDonald, 2004). The water deficit in Oman, however, is estimated at 316 million m3 i.e. 31% of total recharge because of groundwater out flowing due to storage depletion and sea water intrusion (Al Shibli, 2014, FAO, 2009). The total amount of water consumption needed to irrigate the cultivated lands in the Sultanate is 1487 mil- lion m3. Wells are the dominating source of irrigation providing 1204 million m3 followed by Aflaj (single fa- laj, which is an ancient canal based water distribution system) providing 164 million m3 and springs providing 119 million m3 of irrigation water (Fluet et al., 2009; Al- Mamari, 2001; MAF, 2014). Around 907 million m3 of the irrigation water is consumed by the farming prac- tices applying traditional irrigation systems whereas around 580 million m3 of water is consumed by modern irrigation systems (MAF, 2014). Among all cultivated crops in Oman, date palms are the major water consuming plants followed by rhodes grass and alfalfa and then by other fruits and vegeta- bles. The date palm trees consume 558 million m3 (Fig. 3) that represent 38% of total irrigation water and 31% of groundwater recharge for an annual water deficit estimated at 316 million m3. Rhodes grass and alfalfa on other hand consume 457 and 117 million m3 of ir- rigation water respectively while the remaining water for irrigation around 342 million m3 is used to irrigate the other fruits and vegetables (MAF 2014, MAF, 2015; Al-Hattaly, 2005, McDonald, 2004). Besides the fact of predominating the irrigation water consumption, 84% of date palm trees are irrigated by flooding an irrigation Export Food Forage Industry 0 20 40 Date consumption (%) S ec to r Figure 1. Dates consumption in 2014 by different sectors in Oman. 0 100 200 300 2000 2005 2010 2015 Year A nn ua l D at e P ro du ct io n (k To n) Figure 2. Annual dates prodution (Mkg) in Oman. Table 1. Date cultivars annual production (Mkg) in Oman. Date Cultivar 2008 2009 2010 2011 2012 2013 2014 Naghal 24.6 24.9 24.1 28.0 29.7 33.3 37.8 Khussab 27.9 25.4 26.4 26.2 26.1 27.9 30.9 Fardh 20.5 15.8 20.9 16.4 16.9 20.9 24.1 Khallass 12.7 16.9 20.5 20.3 22.4 24.8 23.0 Um Silla 35.2 27.5 29.1 26.3 28.9 31.0 22.4 Mabsali 31.2 19.4 14.7 19.4 19.9 19.5 18.9 Shahel 12.6 16.9 19.7 16.6 17.4 19.1 18.4 Khunaizi 11.3 15.8 15.8 13.7 15.6 17.2 14.9 Qash NA 8.3 9.9 7.0 8.5 9.1 7.8 89Research Article Al-Mulla , Al-Geilani system that causes a loss of half of supplied water (MAF, 2004b). Based on the fact that the water productivity of the date palm trees (Table 2) does not go beyond 0.57 kg of yield/m3 of consumed water and 0.23 OMR revenue/ m3 of consumed water (MAF, 1999; MAF 2014). There are around 300 varieties of date palm trees in Oman (Al- Al-Ruqaishi, 2009) but some of these trees are of low quality and give very low production yet they are planted in large areas while others which are of high quality, are planted in small areas but give high production. Other planted date palms trees in Oman are not productive at all due mainly to salinity problems and also some of them are male type of trees. Although people in Oman prefer Khalas dates they also consume other good quality dates like Nighal, Khessab, Khenaizi and others while the consumption of low quality dates is almost negligible. These ground based information have led to a fact that only one half of planted date palm trees are producing high value dates (Al-Yahyai and Khan, 2015; Al-Mamari, 2001). These findings focused the main objectives of this study which were (1) to evaluate the current status of date palm tree cultivation in the Sultanate; (2) to sug- gest solutions for reducing high consumption of water and improving dates production at same time; and (3). to explore how irrigation water can be saved through in- creasing water productivity by finding alternative date palm cultivation and irrigation practices. Methodology All data related to date palm trees in the Sultanate of Oman were collected and used as a base for this study. These data included scientific studies that determine the country’s groundwater recharge amount accord- ing to FAO (2009), Al-Hattaly (2005) and McDonald (2004). We also included data from agricultural census conducted by the Ministry of Agriculture and Fisheries Wealth which determined the date palm trees planted areas, water consumption, total and per tree production, and their different cultivars (MAF, 2014; MAF, 2004a). Another data set used were those related to dates pro- duction per hectare of land in addition to the technical and economical returns of these dates and water pro- ductivity (MAF, 2004b), historic date production data (MAF, 2015; MAF, 2013; MAF, 2004a and MAF, 1999) and data related to different cultivars of date palm trees in the Sultanate and what are the most productive culti- vars among them (MAF, 2015; MAF, 2000). The dataset indicated that only 50% of planted date palm trees were producing high value dates. Hence, water consumption of the other 50% of lower quality date palm trees can be considered as water loss and removing these types of trees will result in water saving by 50% of total date palm water consumption which is 38% of total irri- gation water. Furthermore, 84% of date pam cultivations are under traditional irrigation systems which consume around 468 million m3 of irrigation water. According to reported water saving using modern irrigation systems over traditional methods (e.g. Reilly, 2005), around 50% of the water cunsumption could be saved if switching to modern irrigation systems. Water productivity of the proposed changes on date palm cultivations is based on above data and analysis that is calculated in terms of the drop per crop (yield) and the economic return (revenues) using the following two equations: WP y = Y W (1) WP e = R W (2) Where WPy is the water productivity based on yield (crop per drop) in kg·m-3, WPe is water productivity based on economic return in OMR·m-3 , Y is date palm tree yield in kg, W is amount of irrigation water con- sumed to irrigate the palm tree in m3 , and R is the reve- nue in Omani Rials (OMR). Results and discussion As mentioned earlier date palm trees consume 38%, i.e. 558 Mm3 of the irrigation water in Oman, hence, the water loss due to planting of low value date palm trees accounts for (0.5 x 38 = 19%), i.e. (0.5 x 558 = 279 mil- lion m3) of irrigation water. This means that out of 1487 million m3 of total irrigation water, only 279 million m3 will be used to irrigate the date palm trees while the remaining 279 million m3 could be saved for other wa- ter usage after removing low quality types of date palm trees. By replacing the traditional irrigation systems which are applied in 84% of the proposed reduced date palm cultivation, this means about (0.5 x 0.84 x 279 =117) an 0 200 400 Alfalfa Date Palm Rhodes Grass Vegetables Crop W at er c on su m pt io n ( M m 3 yr −1 ) Figure 3. Dates consumption in 2014 by different sectors in Oman. 90 SQU Journal of Agricultural and Marine Sciences, 2015, Volume 19, Issue 1 Increasing water productivity enhances water saving for date palm cultivation additional 117 million m3 of irrigation water could be saved for other water consumption purposes and only (279 - 117 =) 162 million m3 will actually be needed to irrigate the high quality types of date palm trees. By combining both practices of avoiding planting low quality date palm trees and introducing modern irriga- tion systems, the total water saving can reach up to (279 +117 = 396) 396 million m3 that can be used in reducing the groundwater recharge deficit and increasing water productivity. These practices will encourage planting other types of crops of high quality and value which will contribute in increasing the economical return to the farmers and to the country. The water productivity, after introducing the pro- posed changes mentioned above of the cultivation and irrigation practices of date palm trees, can be calculated using equations 1 and 2. We showed above that the total production of date palm trees in 2014 was 317 million kg of dates and that only 50% of planted dates tress should be kept to account for high quality and production trees while the other 50% should be removed as it consists of low quality, low productive, or non-productive types of date palm trees. If we we assume that high quality and yield dates have contributed to total production in 2014 by as much as 80%, i.e. with a production of (0.8 x 317 =), the produc- tion of these “good quality” trees was 253.6 million kg. We also showed above that by replacing traditional irrigation with modern systems would reduce irrigation water consumption to 162 million m3 to irrigate the high quality types of date palm trees. If we consider that the average price of dates was 0.400 OMR per kg, the water productivity based on eco- nomic return can be obtained as [(0.400 OMR x 253.6M kg) / 162M m3] = 0.63 OMR/m3, while the water produc- tivity based on yield (crop per drop) can be obtained as (253.6M kg / 162M m3 = 1.56 kg/m3). Therefore, introducing the above mentioned changes of the cultivation and irrigation practices of date palm trees will increase the water productivity by 64% from 0.57  kg·m-3 to 1.56  kg·m-3 and from 0.23  OMR·m-3 to 0.63 OMR·m-3. Conclusion Date palm trees consume 558 million m3 that is 38% of total irrigation water and 38% of groundwater recharge. The water saving recommendation in this study was based on the above mentioned data in addition to the in- vestigation on the water loss during irrigation practices. 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