Increasing water scarcity and changing weather patterns in Central Asia worry policymakers and scientists alike. So much research in the region is focused on ways to cope with the emerging environmental challenges. Scientists are breeding more resilient crop varieties and offering water-efficient technologies to farmers and other land users.
Two problems, however, call special attention. First, most staple crops cultivated in the region require lots of water. Locally-grown potato varieties, for example, need between 3,500 and 8,000 m3 of water per ha. This can be as much as 8,000-9,000 m3 per ha for winter wheat, although only about 60 per cent of the total water consumption comes from irrigation and the rest from rainfall. Second, irrigation practices are far from best, and indiscriminate use of water causes problems. As Dr Jumanazar Ruzimov, of Urgench State University in Uzbekistan, notes, a surplus of 2,500 m3 of water per ha can bring 1,250 kg of salt to the field and increase the water table by 1 m.
Improving the situation is high on the national and regional research agendas. Together with research partners in Central Asian countries, the CGIAR Regional Program for Central Asia and the Caucasus, a consortium of national and international research institutions, also contributes to resolving water-related problems in the region. And this work was at the center of a recent meeting in Tashkent, Uzbekistan, to discuss measures to increase water use efficiency within the framework of the CGIAR Research Program on Dryland Systems. Some 20 scientists from national and international research institutions met on 10 June 2014 to look at how water-efficient crop varieties and technologies can help. Participants agreed that improved crop varieties boost water productivity. For example, some early-maturing legumes grown in June-September need watering only once or twice. Dr Ravza Mavlyanova, of AVRDC - The World Vegetable Center, singles out mungbean as one of the water-efficient crops, which also improves soil fertility. And it can be used as a catch crop. In Uzbekistan, a number of improved varieties like 'Zilola', 'Marjon', 'Durdona' and 'Turon' have been released to date. Another crop is potato. Mr Kahramon Jumaboev, of the International Water Management Institute (IWMI), says that potato yields can go up by as much as 40 per cent if stress-tolerant varieties are cultivated and water-saving technologies used. To that end, IWMI and CIP, an international potato research center, have carried out a series of field trials since 2012 to study the effect of different irrigation practices on yields of the varieties 'Sarnav' and 'Sante' in the Fergana Valley, Uzbekistan. And the results have been submitted in a paper to Irrigation and Drainage, the official journal of the International Commission on Irrigation and Drainage, and published in booklets and brochures for practical use by farmers.
There are various approaches and technologies that can help to save water. Prof Abduhalil Kayimov, of Tashkent State Agrarian University, and Dr Muhabbat Turdieva, Regional Project Coordinator at Bioversity International, point out that agroforestry practices also have potential for increasing water productivity. It is well established that trees and shrubs enhance ecosystems. By growing trees with crops, it is possible to improve yields, reduce soil loss, conserve soil moisture and reduce the effects of agriculture on the environment. For example, cotton fields protected by tree stands require less water due to soil moisture and water conservation. Trees and shrubs can also serve as windbreaks. In some cases they reduce wind speed by as much as 60-80 per cent compared with open areas, which saves soil moisture and crops from lodging. Furthermore, relative humidity in such areas is higher by 10-20 per cent and air temperature is lower by 10-25 per cent. In agriculture, the amount of water, fertilizers and other resources used also depends on field levelling. So the advent of laser-controlled land levelling equipment was a significant advance in surface irrigation. Laser-levelled fields help to achieve substantial water savings and an increase in crop yield and quality. By contrast, traditional land levelling results in increased irrigation, leading to higher salinity levels. Dr Oybek Egamberdiev, of the Khorezm Rural Advisory Support Service, a not-for-profit organization at Urgench State University, says that if the slope of a field, that is the ratio of the difference in height between two points in a field to the horizontal distance between these two points, is 5 cm, then some 500 m3 of additional water is used per ha, bringing 250 kg per ha of additional salt into the field and increasing the groundwater level by 0.2 m. The slope is, however, 1-3 cm if a field is levelled with laser-controlled equipment. According to Dr Egamberdiev, the results of laser land levelling experiments in several districts in Khorezm Region of Uzbekistan proved encouraging. A comparison of traditional land levelling and laser land levelling effects on winter wheat and cotton in 2010 showed that a water saving of 1,500 m3 per ha can be achieved for winter wheat and 2,000 m3 for cotton. More importantly, yields were higher: 4 tons per ha with traditional land levelling and 4.4 tons per ha with laser land levelling for winter wheat, and 2.5 tons per ha and 2.75 tons per ha respectively for cotton. Dr Egamberdiev adds that because irrigated agriculture accounts for about 90 per cent of the total crop production in Uzbekistan, benefits of this technology could be enormous. Scientists also propose conservation agriculture as another way to cut down on irrigation. Conservation agriculture is a set of soil management practices that minimize the disruption of soil structure, composition and natural biodiversity. One of its main benefits is water conservation as this approach requires much less water due to increased infiltration and enhanced water-holding capacity from crop residues left on the soil surface. Mulches also protect the soil surface from extreme temperatures and greatly reduce surface evaporation. By some estimates, water savings can be as much as 20-25 per cent.
Researchers agree that there is enough to offer to farmers and other land users in the region. But uptake is lagging for various reasons, including lack of knowledge and skills. So there is continued effort on training and development, and knowledge is shared through various events involving specialists and farmers. Much is also being done by the CGIAR Regional Program. For example, the International Center for Agricultural Research in the Dry Areas and national partners organized a series of training courses in Azerbaijan, Kazakhstan and Uzbekistan in the past few years under an FAO-funded project to promote conservation agriculture practices in irrigated areas. Some 150 people have been trained since 2013. CIP and IWMI have been helping farmers and agronomists to learn best practices in potato cultivation and irrigation under a three-year BMZ/GIZ-funded project. As part of this initiative, 35 people from Fergana and Andijan regions took part in a training course on 14 June 2014 in Markhamat District of Andijan Region, Uzbekistan.
National governments are committed to boosting the adoption rates of water-saving technologies. In Uzbekistan changes were made in 2013 to the Tax Code, exempting farms using drip irrigation from the single land tax for five years. And Kazakhstan has been implementing policies, including an equipment subsidy program, to promote conservation agriculture. But many technologies are still thin on the ground in the region. Conservation agriculture is slowly taking off in some countries, while other approaches and technologies are finding their way into agricultural production. Scientists fret that there is still a way to go to achieve large-scale adoption of water-saving technologies. As Dr Shukhrat Mukhamedjanov, senior researcher at the Scientific Information Center of the Interstate Coordination Water Commission of Central Asia, notes, it is necessary to develop a system for transfer of innovative technologies to Water User Associations (WUAs) and farms. He points out that efficient water use is hindered by such issues as weak water management mechanisms at WUAs, low qualifications of WUA specialists and lack of appropriate water accounting procedures. Breeding new varieties and developing water-efficient technologies is a lengthy process, but making farmers and other land users in the region adopt them often takes even more time. It is hoped that farmers will soon learn the knowledge developed by science, and policymakers will do more to make this happen sooner rather than later. Water is a finite resource, after all.