ICARDA CARAVAN 11

Diamonds, gold, oil, land, even spices, have all led to conflict of one kind or another. Yet a simple molecular combination--H2O-- may provide the new century with its most persistent source of cross-border disagreement.

t's not just that most of our body comprises water and we each need a vital daily intake. For more than 5,000 years water has been managed to maximize its role in agriculture; many of those techniques were adopted and spread usefully in Europe, West Asia and North Africa (WANA), thanks to the influence of Imperial Rome.
         Even if the Romans weren't the first plumbers, they were certainly instrumental in introducing civic baths, central heating, drains and rudimentary water closets to European, African and West Asian countries within their control. Their enduring legacy is a priority allocation of water for urban use and a decline in its availability for agriculture.
         The rapid expansion of population in many already-stressed developing countries is generating yet more demand for fresh drinking water. World Bank estimates (1996) suggest that by 2025 around 3 billion people in 52 countries will face either periodic shortages of water or a chronic scarcity.
          The historians of two millennia ago record that much of what is today regarded as arid land in ICARDA's mandate region flourished with field crops and productive orchards. It is likely that the Mesopotamians were the first engineers to harness the waters of the major rivers--in their case, the Tigris and Euphrates--for grand agricultural irrigation schemes.
         However, water engineering on a grand scale always seems to turn up victims - human or environmental - as well as beneficiaries. Few individuals fully welcome being shifted permanently from homes and land in favor of dam and other storage projects, however great the advantages these schemes bring on a wider scale.
         No clear international law exists to govern cross-border disputes over water flow. The World Water Convention, coordinated by the World Water Council, is keen to develop a statement for each of the different regions of the world. This will be based on how countries in those regions see water issues developing over the next 25 years. From the information to be collected it will be possible to develop advance warning scenarios for crisis management and for sustainability.
        The United Nations Environment Programme (UNEP) has already come up with a 'water exploitation index' to measure the amount of water used by a country as a percentage of its renewable water resources such as rainfall and river flows. By this measurement, an index of more than 50% indicates potential future difficulties. Tunisia, Egypt, and Libya, for example, all far exceed 50%, and Morocco and Algeria are expected to follow suit as they increase water use to supply their rapidly expanding populations.
         For the moment, only a few riparian neighbors have been able to settle differences on water extraction. India and Bangladesh argue over the Ganges while Iraq, Syria and Turkey discuss the Euphrates but have no formal treaty arrangement on either the volume or quality of water leaving Turkey for its more southerly downstream neighbors.
          There are exceptions. Sudan and Egypt now have an agreement on the level of extraction each may make from the Nile.
         Working with the Syrian national program, ICARDA has been able to more than double wheat yields in Syria by improved irrigation management. Despite this and other advances in water use efficiency, Dr Theib Oweis, who is a water management and supplemental irrigation specialist at ICARDA, sees the potential for disagreement between upstream and downstream countries in providing water to their burgeoning populations. "Some countries are starting to feel they can't manage their agriculture and food security programs, and provide enough waterfor drinking with the supply they have available," he says.
         "These countries may then start to look at shared water resources such as the major rivers that extend beyond their borders."
         Water quality in turn becomes an issue when technically-proficient farmers in the upstream country install extra irrigation to improve crop yields. Most open systems suffer from evapotranspiration leaving a steadily increasing legacy of salt which enters the soil profile before being leached out.
          The resulting saline drainage waters may have to be pumped back into the river supply to further fuel discontent among downstream users. Egypt is able to dump unwanted high saline drainage water in the sea but this is not an option for countries bordering the Tigris and Euphrates.
         The cards remain stacked, therefore, in favor of the upstream countries. Like their neighbors they face competing demands from indigenous industry, agriculture and urban development. In theory, surplus water that Turkey now dumps in the Mediterranean could be diverted to cater for the needs of agriculture and urban areas over much of the Middle East.
         Dr Oweis believes countries will eventually be forced to sit around the conference table as water becomes scarcer. He points to Jordan's plan to pump ground aquifer water 350 km from the south of the country to Amman. With an elevation difference of 1,000 meters between source and destination, this will be a remarkable feat of engineering at an estimated cost of around $1 per cu meter. Source water from elsewhere at 50 cents per cu meter and you have a worthwhile alternative. Provided, that is, society accepts the premise that some subsidy will continue to be needed for sectors such as agriculture.
         It is a brave government indeed that proposes putting anything like a real monetary value on the cost of water. In many countries with a significant dry area, water is regarded as a gift from God. Few governments charge consumers for little beyond the cost of operating the system that delivers water for domestic or agricultural consumption. Persuading society that it should be paying to subsidize vital food production requires a major change in collective thinking.
      There is, however, much that is being done to make best use of water at present levels of supply and demand. Agriculture may still take 75% of available water in the Middle East and North Africa but it is steadily losing out to domestic requirements. Scientists such as Dr Oweis and his ICARDA colleagues are working to ensure the efficiency of water use for food production is kept high in many ingenious ways, particularly in those dry regions around the Mediterranean.
           Where rain does fall erratically, it is frequently spread so thinly it either evaporates or is of little lasting benefit for crops and vegetation. Water harvesting concentrates rain water from very localized areas or up to

several hundred square kilometers by building barriers and channels to guide runoff into ponds, reservoirs or lakes. In essence, an achievement not all that different from the Romans and their predecessors who likewise collected rainfall and stream water for use where it does the most good.
         Rainfed wheat yield in the WANA region averages about 1 tonne/ha, in a range from 0.5-2 t/ha depending on rainfall pattern as well as fertility and crop variety, but always well short of the potential of 5-6 t/ha achievable from well-watered sites. In the dry areas, farm production performance is now evaluated in terms of water-use efficiency (WUE), not yield per unit area, since it is now clear that water is the greatest limiting factor.
         By this reckoning, the average output of wheat in WANA is about 0.35 kg grain per cu meter of rain. Good management and enough seasonal rain at the right time takes this up to 1 kg/cu m. Supplemental irrigation using harvested rainwater or surface water can dramatically increase WUE by more than 2.5 kg/cu m over rainfed production. This is done by ensuring that extra--albeit limited-- water is available to alleviate severe moisture stress when the wheat plants reach their most critical growth and ear filling stages.
          This supplemental irrigation (see p14) makes considerably more efficient use of water than in fully irrigated areas where the rainfall contribution is so exceeded as to have little effect on yield.
          Quite simply, many farmers currently use too much scarce water, and that applies both to full irrigation and supplemental management systems needing a third to two-thirds less, says Dr Oweis. It comes back, in part at least, to that low cost of water. Where there is a charge imposed it is often just a few cents per hectare, irrespective of how much water is actually used. This encourages unsupervised over-extraction. The energy cost of pumping is usually then the only constraint on enthusiastic farmers.
         Dr Oweis estimates at least one-third of the full irrigation requirement could be saved without any loss in wheat productivity. ICARDA has developed recommendations for farmers to determine the correct level of supplemental irrigation for given rainfall zones, seasons and level of inputs such as nitrogen fertilizer.
         This is also giving plant breeders more work. They have had considerable success in transferring genes which confer drought stress resistance from wild species into cultivated varieties of wheat and barley. Now they are selecting varieties, which can also show the greatest response to additional water.

        Water-use efficiency can also be stepped up for crops other than wheat both through improved management and plant breeding. Biotechnology tools have allowed ICARDA scientists to identify genes for cold tolerance as well as drought resistance. As a result, varieties of lentil and chickpea--both traditional spring crops--are being developed for winter sowing when the newly established plant will have the advantage of a ready supply of moisture.
         Less dramatically, bringing plant-ing date forward by a week or two can be enough to increase plant survival. Tillage practices that conserve soil moisture are often overlooked by growers with a fixed management approach until the effects of extra yield are physically demonstrated.
        On both micro- and macro-scales, there are improvements in water use to be gained from blending water of varying qualities to produce a standard acceptable to individual crops. This can be done at farm level with mixtures of surface and borehole water or on a national scale as in Egypt. The Al Salam Canal will take 10-15 cu m a second of mostly drainage water from the Nile Valley under the Suez Canal to Sinai for blending with groundwater.
          Super-efficient trickle irrigation is now being used extensively, particularly in water-hungry Jordan, but it is only economic when used on higher value cash crops such as vegetables. The cost of installation is currently too high to make it worthwhile even for major strategic crops such as cereals and other small grains, which have a much lower cash value.
           All this successful application of science and technology is aimed at releasing more water for agricultural production, says Dr Oweis. "By releasing this additional water, we reduce the level of scarcity, and indirectly reduce the potential for conflict."