Taha - role of biosaline agriculture
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    Taha - role of biosaline agriculture Taha - role of biosaline agriculture Document Transcript

    • THE ROLE OF BIOSALINE AGRICULTURE TO COPE WITH WATER SCARCITY IN THE WANA REGION Faisal Taha and Shoaib Ismail International Center for Biosaline Agriculture, Dubai, United Arab EmiratesWater Scarcity and ManagementThe allocation of the valuable fresh water resource vis-à-vis the demands has become acritical issue for the last two decades. The prioritization of different water-use sectors, theinclusion of new water use sectors and the availablity of limited water resources had a directimpact on the agriculture sector that uses 70-80% of the fresh water worldwide, and 80-90%in the WANA region. Many water-scarce countries have been tapping the shallow- and deep-aquifers (non-renewable) to meet their growing demand for water. This water has beenused for all the sectors to meet the deficit and as a result un-controlled abstraction has ledto intrusion of sea water and other marginal water in the aquifers. Thus, the quality of thewater has deteriorated significantly. Furthermore, as this water becomes more and moresalinized, the impact on conventional agricultural production becomes more and moreevident in terms of reduced quantity and quality of agricultural commodities.Available renewable water resources per capita across North Africa, the Middle East, andSouth/Central Asia are the lowest in the world and will decrease further with continuingstrong economic and population growth in the region (Figure 1). The West Asia and NorthAfrica (WANA) region are currently at 1,100 m3 per year and projected to further drop byhalf by 2050. Aus/NZ LAC N America ECA SSA EAP W Europe SA WANA 0 5 15 10 20 25 30 35 1000 m3 / year Figure 1. Annual renewable water resources worldwide. (Source: FAO Aquastat)In order to have a balance between the water resources available and the water-use sectors,it is imperative to (i) prioritize the water needs sector-wise; and (ii) look for additional ornew water resources. The latter will include ‘marginal water’ or poor-quality water,including saline/brackish water and wastewater that can be either (i) supplemented withfresh quality water; and/or (ii) replace the fresh water for growing certain crops/productionsystems.This paper will focus on marginal quality water and land resources, and their contribution toreducing the demands on fresh water for agriculture in the water-scarce WANA region.Clearly there is a need to re-think the ways in which saline water can be used for irrigationF. Taha and S. Ismail, 2011 WANA Forum Consultation 1 Medenine, Tunis, February 2011
    • and to develop appropriate technical and policy options for productive use in aridenvironment.Biosaline agriculture and its potential under water scarce conditionSalinity has been known to significantly reduce agricultural production worldwide.Significant portion of arable land have been salinized to different extent because of watermanagement issues, whether that is linked to irrigation practices or inefficient drainagesystems. Five percent of world’s cultivated lands are salt affected (Suarez, 2010; Taha andIsmail, 2010; Ghassemi et al., 1995). In addition, about 20% of land within the irrigated areais affected by salinity problems with over 30% decrease in productivity. Furthermore 2 m.haof irrigated land are lost annually due to salinization (Postel, 1997).The International Center for Biosaline Agriculture (ICBA) mandated to work in 56 countries,most of them being in the arid and semi-arid regions has been emphasizing the inventory ofmarginal (mainly saline) water resources in WANA. The target regions have been the WANA/CWANA, GCC, SEA and the CAC regions. In its attempt to look at the potential of usingsaline/brackish water for agricultural production systems, it undertook a study (ICBA, 2003;Stenhouse and Kijne, 2006) to investigate the saline water resources in some WANAcountries (Table 1). The study showed that approximately 14% of the irrigated area in thetarget countries has the potential to be used for ‘biosaline agriculture’, where the salinity ofthe groundwater ranged from 3000-16,000 ppm (~ 4 – 23 dS.m-1).Biosaline agriculture is a specialized form of agriculture whereby crops and croppingpatterns are adjusted to the prevailing conditions of saline/brackish water and land amdhence the system has minimal, is any use of fresh water and hence the system has minimal,if any use of fresh water. In addition to having conventional/non-conventional/specializedcrops/plants, an important component is the management of land and water resources tooptimize the production and make it environmentally safe. This leads to three importantfactors, the given scenarios of climate change, the prevailing land and water quality, thetargeted production system (the crops to be grown and the market for the crops).Biosaline agriculture focuses on the development and propagation of sustainable vegetativealternatives for salt-affected lands that are deemed unsuitable for conventional farming,including: (i) more effective soil/water management and improved crop salt-tolerance, and(ii) the domestication of halophytes for commercial and/or environmental cultivation. Theultimate goal of this discipline is to help provide food and water security for futuregenerations by conserving and rehabilitating scarce resources (water and arable land) ,substituting them for more abundant saline ones in newly emerging agro-ecosystems.Two approaches have been associated with the concept of improving agricultural productionsystems; (i) improving/developing high yielding crops/varieties – these are usually lesstolerant to environmental stresses; and (ii) developing/adapting crops and systems to theprevailing stress conditions. It is widely accepted that the first approach may be feasible upto certain extent of stress (salinity) levels, since most of the crops (glycophytes) have agenetic make-up that has been pushed up to its maximum threshold for salinity tolerance.The threshold salinity level only in case of some species have made a real progress,otherwise for most of the species, the increase in tolerance limit has not been significant(Table 2). Flowers and Yeo (1995) suggested options to develop salt tolerant crops in termsof priorities: (1) develop halophytes as alternative crops; (2) use inter-specific hybridizationto raise the tolerance of current crops; (3) use the variation already present in existing crops;(4) generate variation within existing crops by using recurrent selection, mutagenesis ortissue culture, and (5) breed for yield rather than tolerance.F. Taha and S. Ismail, 2011 WANA Forum Consultation 2 Medenine, Tunis, February 2011
    • Table 1. Availability of brackish water resources in some of the WANA countries.Country Usable Brackish Salinity Range Basin(s) Equivalent Fresh Potential Land for Total Irrigated Percent Potential 1 2 3 4 Land for Biosaline Water Resources Water Volume Biosaline Agriculture Area (1990) Agriculture of Total Irrigated Area 3 3 (million m /year) (ppm) (million m /year) (Hectares) (Hectares) Col. 1 Col. 2 Col. 3 Col. 4 Col. 5 (1-LR)x Col. 1 Col. 1/WR Col. 3/ Col. 4Jordan 246 3,000 - 10,000 Jordan Valley, 197 25,900 63,000 41% Wadi Araba, Southern GhorsSyria 768 4,000 - 8,000 Palmyra, Sewwanah 640 74,600 693,000 11%Oman 320 6,000 - 15,000 Najd, Central 256 25,200 58,000 43% RegionYemen 300 3,000 - 8,000 Tihama Plain 250 38,500 348,000 11%Algeria 470 4,000 - 16,000 Souf Valley, 392 87,000 384,000 23% Ouargla Basin, Oued Rhir ValleyLibya 208 > 5,000 Ghadames Area 173 33,000 470,000 7%Tunisia 333 5,000 - > 7,500 South and Central 278 47,600 300,000 16% RegionsTotal 2,645 3,000 - 16,000 2,185 331,800 2,316,000 14%1 Calculated as follows: ICBA, 2003; Stenhouse and Kijne, 2006 Source: Jordan: 225 million non renewable from Sandstone aquifers, 20 million Jordan Valley Zerqa group, 1 million Wadi Araba Alluvium Syria: 750 million annual recharge for various aquifers, 18 million Palmyra, Sewwanah areas Oman: 260 million annual rechargeto improving agricultural production within regions. Another approach for Al Batinah and Salalah, 60 million for Najd and Central the context of biosaline Yemen: 250 annual recharge for varioustowards the environment-based strategies where crops are agriculture is to move aquifers, 50 million in Wadi Tuban Delta Algeria: drainage water estimated as 10 percent of total water used for irrigation in the South selected/developed based on specific site criteria’s. This has become more important since Libya: estimated as return water, 10 % of total water applied for irrigation Tunisia: 194 million drainage water fromis farRejim Maatoug, the development of 85 million renewable(conventional the increase in salinity Jerid, rapid than Tozeur, Kebili, and Gabes, crops/species South and crops). In general, most of unused deep aquifers Central phreatic aquifers, 54 million the irrigated areas that have turned saline either are newly saline23 areas (EC: 4-10 dS.m-1) or that and gone %) depending on salinity range Leaching requirement (LR) varies between 0.2 (20 %) has0.25 (25 through the process of secondary salinization, with Average annual water requirements (WR) are: 0.95 m for Jordan, 1.03 m for Syria, 1.27 m for Oman, 0.78 m for Yemen, 0.54 m for Algeria, 0.63 m for Libya, salinity ranges between 10-25 dS m-1). There also exist areas where salinity is more than 25 and 0.70 m for Tunisia. These factors were taken from IWMI Research Report 19 (1998). -1 IWMI Researchm and only limited type of agricultural production systems can be practiced successfully. dS Report 19 (1998).4 Crops and production systems can be placed into different categories based on the genetic make-up of the plants and the salinity tolerance levels. These include food, feed/forage, fuel, oil, fiber crops, landscaping, etc. Most of the horticultural crops fail to grow economically beyond 5-6 dS m-1, whereas, a number of glycophytic crops can grow up to 10 dS m-1 salinity level. The latter group still requires land and water managements to avoid any salinity build-up over period of time. At salinities of 10-25 dS m-1, the major categories of production system includes forage and landscaping plants (few glycophytes and mostly halophytes), whereas, at higher salinities of >25 dS m-1, only halophytes can support forage, fuel and coastal rehabilitation systems. Sea-water based production systems are very few. A number of studies have been undertaken looking at the potential of ‘using salt-affected lands and saline irrigation water’ for agriculture, or in other cases are ‘practicing’ agriculture under saline conditions (since no other alternatives are present). The following section will give a brief of recent biosaline agriculture work, and more specifically in the WANA region (where ICBA has been working with partner countries). F. Taha and S. Ismail, 2011 WANA Forum Consultation 3 Medenine, Tunis, February 2011
    • Table 2.Salt tolerance of some of the crop species. Maas and Hoffman, 1977 Maas, 1986 Anonymous, 2003Plant Species Threshold (dS/ Slope (% Threshold Slope (% Threshold Slope (% m) dS/m) (dS/m) dS/m) (dS/m) dS/m)Festuca eliator 3.9 5.3 3.9 5.6(Tall Fecsue)Glycine max 5.0 20.0 5.0 20.0(Soybean)Helianthus 4.8 5.0 5.5 25.0annuus(Sunflower)Hordeum 6.0 7.1 7.4 9.6vulgare(Barley forage)Lycopersicon 2.5 9.9 2.3 18.9lycopersicum(Tomato)Oryza sativa 3.0 12.0 3.8 5.1(Rice)Sorghum 6.8 16.0 7.4 8.4bicolor(Sorghum)Trifolium 1.5 5.7 2 10.3alexandrinum(Berseem)Development of Biosaline Agriculture in the WANA region:With increase in salinity levels of water and soil, it becomes less economical to grow alfalafa,maize and other conventional forage grasses, because of high water needs and relativelylower yield (being low to moderately salt tolerant). In some cases, more salt tolerant plantspecies are available but their water requirements are still very high (e.g. Rhodes grass).Alternate forage production systems are therefore essential to be introduced under suchsalinity conditions. These plant species needs to be salt tolerant, have a high water useefficiency, should have a good forage quality (in terms of digestibility an palatability), shouldnot have any negative environmental impact and should make the whole systemeconomically viable.These ‘alternative production systems’ could be categorized into two; (i) the conventionalforages (including dual purpose crops and other salt tolerant glycophytic forages); and (ii)non-conventional forages (including salt tolerant grasses, shrubs, trees and halophytes).The conventional forage that has been tested by ICBA in WANA region and introduced infarming system mainly include, barley, sorghum, pearl millet, triticale, sugar beet. Legumesmainly include, Sesbania and Leuceana. Studies have shown that a number of accessions ofLeuceana studies have shown a large variation in dry matter productivity. The species L.collinsii, L. lanceolata, L. lempirana, L. macrophylla, L. magnifica, L. shannonii andL. trichoides all had high dry matter digestibility (>65%), low levels of non-digestible fiber(<26%) and low concentrations (<1.5%) of condensed tannins (Dalzell et al., 1998). Barley,sorghum and pearl millet have shown an excellent potential in many regions, from CentralAsia to the Mediterrneian region, both in terms of high yield and good forage quality atsalinity levels ranging from 8-15 dS/m (ICBA, 2007, 2008).The non-conventional forages have been widely screened, developed and introduced indifferent farming production systems. The most common species includes the grasses(Distichlis, Sporobolus, Paspalum, Leptochloa, Chloris, Lollium, Festuca, etc.) studiedworldwide (Taha and Ismail, 2010; Suyama etc al., 2007; Alhadrami et al., 2005). ProductivityF. Taha and S. Ismail, 2011 WANA Forum Consultation 4 Medenine, Tunis, February 2011
    • ranges vary from low to high (10-40 tons dry matter.ha-1.yr-1) depending upon climate, soiltexture and salinity, irrigation water quality and quantity, and management practicesapplied.Salt tolerant tree legumes and other fast growing tree species has received a lot of attentionfor forge production and rehabilitation of degraded saline wastelands. Among them, Acaciaand Prosopis species have been most extensively studied, especially under dry and salineconditions, both for yield and nutrient values (Craig, et al., 1991). For most of the speciesstudied the in vitro dry matter digestibility (IVDMD) was >40% with crude protein rangingbetween 8-17% of dry matter.Acacia ampliceps is reported to grow in different salinity ranges, with 40%-60% survival innorthern Queensland at ECe up to 20 dS.m-1 or higher (House et al. 1998); under dry arid andsemi-arid conditions of the UAE, with > 95% survival, irrigated with water of salinity rangingbetween ECiw 30 and 35 dS.m-I (lCBA 2006, 2007); and in the Central Kyzylkum desert ofUzbekistan, grown with drainage water salinities ranging between ECiw 12.5 and 18.1dS m-I(Toderich et al., 2009). Ismail et al., (2007) has reported various responses of the A.ampliceps seedlings when grown on lighter soils in UAE, Jordan, Syria, Oman, and Tunisia,with > 95% survival after 4-years at ECe of 10-25dS m-1.ICBA have initiated many multi-countries project activities with the National AgriculturalResearch (NAR’s) program for (i) testing different alternate production systems; (ii)implementing integrated management program of land, water, crops and livestock; (iii) localseed production of salt tolerant crops, forages and halophytes.The IFAD supported ‘Forage project’ looked at the potential of growing forage using salinewater in seven countries (Jordan, Oman, Syria, Pakistan, Palestine, Tunisia and United ArabEmirates). The project focused on four important factors; (i) eradicating poverty and hunger;(ii) promoting gender equality; (iii) ensuring environmental sustainability; and (iv) developingglobal partnership. The initial focus was to identify, evaluate and introduce salt tolerantforage (both conventional and non-conventional) species, under saline conditions, in thepartner countries through the national agricultural system. The second phase was to selectthe successful genotype of the different species, multiply them and upscale activities infarmer’s field. As a result of this, many genotypes of sorghum, pearl millet, alfalfa, brassica,canola, fodder beet among conventional forage have been identified and propagated.Grasses from the genus Cenchrus, Panicum, Paspalum, Sporobolus, Distichlis; shrubsincluding Atriplex spp.; and tree species of Acacia ampliceps have been introduced on largescale in the salt-affected farmer’s fields.The Oman Salinity Strategy (OSS) project looks at developing both short- and long-termstrategies for improving agricultural production in the Sultanate of Oman. Most of thecurrent agricultural areas are facing soil and water salinity problems and there is a decline inthe yield of its major crops. The strategy looks from an ‘integrated approach’ of the availableland and water (both quality and quantity) resources and present scenarios for continuingand/or changing the currently practiced agricultural production systems. This would bebased on hydrology of the areas and the sustainability of aquifers; the abstraction of groundwater related to the intrusion of sea water leading to increased salinity problems; thecurrent state of agricultural production; and the socio-economic factors. Based on theanalyses, the strategy would provide a guideline to (i) improve the management practices –site specific related to salinity problems; (ii) improved genotypes of crops required toimprove production under prevailing salinity conditions; (iii) mitigation efforts to reduce theprocess of salinization, especially the secondary salinization as a result of irrigation practices;and (iv) the impacts of the current agricultural practices on the socio-economy of farmersand on the environment – and vice versa.F. Taha and S. Ismail, 2011 WANA Forum Consultation 5 Medenine, Tunis, February 2011
    • ICBA in collaboration with European and Asian partners are part of the BIOSAFOR project tolook into the potential of salt tolerant plans for biomass – bioenergy. The project is fundedby the European Union Commission. The project looks into the whole approach of applyingbiosaline agroforestry (for bioenergy) on a local, regional and global perspective related tothe different type of salinity conditions. The project provided the baseline information on:A number of tree species/varieties/accession was identified through screening (up to 40dS.m-1) and case-study areas to look at the regional and global potential of using thewastelands with least management to make it economical. Description and categorization ofbrackish water resources for biosaline (agro) forestry production has been prepared to lookat the potential areas in the world where susch system can be economically viable.Other activities included the potential role of ‘saline-produced water’ (water from oilindustry) which after cleaning and removal of hydrocarbons, heavy metals and otherpollutants can be used for non food-chain agricultural production systems (including wood,fiber, landscaping etc.). The process involving phytoremediation through water managementinvolves the degradation of pollutants through microbial activities, has been demonstratedby ICAB in Nimr, Sultanate of Oman. The ‘produced water’ (~10-16 dS.m-1) was used to growsalt tolerant tree-based production systems.The use of ‘returned seawater’ (seawater from prawn farms) at the facility of the NationalPrawn Company (NPC) in Kingdom of Saudi Arabia is another example of using the highlymineralized sea water for halophytic forage production system. The facility located at thecoast of Red Sea produces return water @ of 80 m3.s-1. This water was used with/withoutdilution to initially irrigate wind breaks (Conocarpus and Salvadora) followed by foragegrasses (Sporobolus virginicus and Distichlis spicata).Conclusions:Biosaline agriculture will play an important role in the future of agriculture in many arid andsemi-arid countries and present an excellent opportunity to relief pressure from dwindlingfresh water resources. . All further expansion and/or sustaining the current agricultural areaswill largely depend on how marginal and saline land/water are used for improving food, feedand fuel demands. Improvement in genetic makeup through conventional breeding,biotechnology, etc will remain focussed for high value crops, whereas, forage and fuelproduction sector will eventually be limited to use of the marginalized land and waterresources. Effective management practices and better genotypes (selected from wide rangeof wild species) followed by on-farm optimization for yield, will be the key to provideimmediate relieve to the farmers as short-term strategy. In spite of all the development, along-term planning for agriculture (other than food) represnets a major challenge to theprofessionals and others to come with feasible solutions for sustainable production systemsusing marginal resources.F. Taha and S. Ismail, 2011 WANA Forum Consultation 6 Medenine, Tunis, February 2011
    • References:Alhadrami, G.A., S.A. Al-Shorepy, and A.J. Dakheel. 2005. Effect of feeding long-term Sprorobolus grass hay on growth performance of Awassi sheep. In: 6th Annual UAE University Research Conference, CITI-51-55.Anonymous. 1997. Salinity management handbook. 214 pp., Department of Natural Resources, Queensland, Australia.Craig, G.F., D.T.Bell and C.A. Atkins. 1991. Nutritional characteristics of selected species of Acacia growing in saline areas of Western Australia. Aust. J. Exp. Agriculture., 31 : 341-345.Dalzell, S.A., J.L. Stewart, A. Tolera, and D.M. McNeill. 1998. Chemical composition of Leucaena and implications for forage quality. In Leucaena - Adaptation, Quality and Farming Systems: Workshop 9-14 February 1998. (H.M. Shelton, R.C. Gutteridge, B.F. Mullen, R.A. Bray, Eds.), Vol. 86. pp. 227-246. Australian Centre for International Agricultural Research: Canberra.Flowers, T.J. and A.R. Yeo. 1995. Breeding for salinity resistance in crop plants - where next? Australian Journal of Plant Physiology 22, 875-884.Ghassemi, I., A.J. Jakeman and H.A. Nix. 1995. Salinization of land and water resources. Univrsity of New South Wales Press Ltd., Sydney, 526 pp,ICBA. 2003. Assessment of brackish and saline groundwater availability in selected countries in the West Asia North Africa region. 22 pp. IFAD sponsored short term project report.ICBA. 2006. Annual Report. Dubai: International Centre for Biosaline Agriculture.ICBA. 2007. Annual Report. Dubai: International Centre for Biosaline Agriculture.ICBA. 2008. Annual Report. Dubai: International Centre for Biosaline Agriculture.Ismail, S., F. Taha, K.U. Rehman and N. Akhand. 2007. Potential use of brackish/saline ground water for agriculture and bio-energy in the GCC countries. 2nd Scientiic Conference on water issues in GCC, pp. 26-44. Geographical Society of the GCC countries, Kuwait.Maas, E.V. 1986. Salt tolerance of plants. App. Agric. Res., 1 : 12-26Maas, E.V. and G.J. Hoffman. 1977. Crop salt tolerance: Current assessment. J. Irrig. Drainage Div., Am. Soc. Civ. Eng. 103:115–134Postel, S. 1999. Last Oasis : Facing water scar city. W.W. Norton & Company, New York.Stenhouse, J. and J. Kijne. 2006. Prospects for productive use of saline water in West Asia and North Africa. Comprehensive Assessment Research Report No. 11. Colombo, Sri Lanka, 42 pp.Suarez, D.L. 2010. Extent of global salinization and management options for sustainable crop production. In: Proc. Int. Conf. On Soil and Groundwater Salinization in Arid Countries, 1-7, Sultan Qaboos University.Suyama, H., S.E.Benes, P.H. Robinson, S.R. Grattan, C.M. Grieve and G. Getachew. 2007. Forage yield and quality under irrigation with saline-sodic drainage water: Greenhouse evaluation. Agric. Water Manag., 88 : 159-172.Taha, F. and S. Ismail. 2010. Potential of marginal land and water resources : Challenges and opportunities. In: Proc. Int. Conf. On Soil and Groundwater Salinization in Arid Countries, 99-104, Sultan Qaboos University.Toderich, K.N., E.V. Shuyskaya and S. Ismail. 2009. Phytogenic resources of halophytes of Central Asia and their role for rehabilitation of sandy desert degraded rangelands. Land Degradation and Development 20: 386-396.F. Taha and S. Ismail, 2011 WANA Forum Consultation 7 Medenine, Tunis, February 2011