ICARDA CARAVAN 11

As if severe drought was not enough, what little water is available for crops in the world's driest areas is being badly managed, turning a serious difficulty into a
desperate problem. Many solutions to the challenge of getting more production per unit of water are being explored and found, but sharing ideas through colla-boration is essential to get success in farmers' fields.

Water-use efficiency in cereal growing systems can be improved markedly by replacing traditional fallows with legumes, including vetches. These make better use of the scarce available water and  provide ideal grazing for livestock. There are further benefits for the soil in improved nitrogen and organic matter content.

or millions of resource-poor dryland farmers in sub-Saharan Africa (SSA) and Central and West Asia and North Africa (CWANA), small total rainfall and its erratic, unreliable distribution constrain the achievement of stable, sustainable production systems which would provide them with satisfactory, low-risk livelihoods.
High population growth rates in arid and semi-arid regions increase the demand for food, feed, and other agricultural products.
          At the same time, production increases from fertile lands are known to be declining, forcing people to use also marginal lands. Thus, both marginal and fertile lands are currently suffering from various forms of degradation, including nutrient depletion, soil acidification, soil erosion, and reduced soil water retention.
          Effective soil, water, and nutrient management requires actions not only at the farm level, but also at community, regional, and national levels. The agricultural priority across all dry-area farming systems in sub-Saharan Africa and CWANA is to increase biological and economic yield per unit of water.

OSWU Consortium
One of ICARDA's activities directed at improving the productivity of water use in dry areas taps into knowledge and expertise from countries as far apart as Iran and South Africa, despite distinct differences, among other things, in rainfall distribution.
          ICARDA is, together with the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) and the national research organization of South Africa (ARC-SCW), co-convener of the Optimizing Soil Water-use (OSWU) Consortium. This is a constituent of the CGIAR System-wide Soil, Water, and Nutrient Management Program (SWNMP). The overall goal of the consortium is sustainable and profitable agricultural production in dry areas, based upon the optimal use of the available water.
          It brings together two international agricultural research centers (IARC) and 12 national agricultural research and extension systems (NARES) in Burkina Faso, Egypt, Iran, Jordan, Kenya, Mali, Morocco, Niger, South Africa, Syria, Turkey, and Zimbabwe. By bringing together researchers and farmers from different environments, the OSWU Consortium promotes fruitful exchange of ideas, experience and, most important, practical techniques to combat the effects of water scarcity, and to sustainably improve production, security, and livelihood of the farmers in dry areas of WANA and SSA.
           An important achievement is a compendium of the state-of-the-art of research in the 12 member countries. Future outputs include generic tools that can be used by the other consortia and relevant eco-regional programs as well. It is OSWU's strategy to build on existing scientific knowledge and indigenous practices of soil and water conservation.
           Exchange of scientific and indigenous knowledge and technologies between countries and regions is a key element in the Consortium's approach. Therefore, linkages among and partnerships with NARES, international agricultural research centers, advanced research organizations, non-governmental organizations, and local farming communities play key roles in OSWU's strategy. These linkages increase and facilitate the spread of knowledge about the very specific techniques required to boost agricultural production in the varying ecosystems found in dry areas. In rainfed fields, improvement is possible only by conserving rainfall water in the root zone of crops (including shrubs and trees), and by managing the field and the crops to use this water more efficiently.
           However, actual water-use efficiency in current farming systems in the drought-prone countries of CWANA and SSA is often very low, and a surprisingly small proportion of the available water is actually transpired by the crop. The water losses at the field-level include surface runoff, percolation below the rooting zone, evaporation from the soil surface, seepage in deep cracks, and transpiration by weeds, but vary according to site- and situation-specific conditions and are often not well quantified.
              Viable farm-level techniques, such as those developed by ICARDA and ICRISAT for their mandate areas, are applicable in many other dry countries to reduce these losses and to increase the capture and retention of incoming water as well as maximize the proportion of water that is productively transpired by the crop. The development of water-efficient cultivars is one way to achieve this. Such new varieties, which are often developed by national programs from ICARDA-sourced germplasm, usually require improved soil, crop and cropping system management.

Improving productivity
Recent agricultural research by ICARDA and other international and national centers has enabled farmers to overcome many of the constraints previously limiting their crop yields. However, in most rainfed farming systems, the major constraint that farmers cannot influence remains low and erratic rainfall. The technologies required to increase outputs and input-use efficiencies (e.g. water- and nutrient-use efficiencies), must fit the land-use system of resource-poor farmers, and must conserve the natural resource base.
        The main agronomic strategies to intensify crop production systems are (i) soil and water management, and (ii) cropping system management, with strong emphasis on soil fertility management. Soil and water management recommendations to improve the productivity of scarce and erratic rainfall can be grouped under three main headings: improved tillage practices, different water harvesting techniques, and erosion control measures. Cropping systems management to improve water productivity is first concerned with the type and sequence of crops grown. The choice of appropriate rotations, intercropping or relay cropping determines to a great extent the productivity of rainfed farming systems.
          In CWANA, introducing legume crops in place of a fallow period can increase a production system's water-use efficiency considerably in many dry areas. A number of national programs have taken pasture and forage legume germplasm from ICARDA to develop appropriate varieties of vetch, chicklings or medics.
           About 30 million hectares of land is left fallow in CWANA every year. If only 70% of this land could be sown to forage legumes, it would produce enough feed for 80 million sheep. Moreover, there would be an influx of 1.4 million tonnes of nitrogen from symbiotic nitrogen fixation per year.
          Use of medic and vetches in the cereal-based rotation over a period of 10 years in ICARDA trials showed a significant increase in total nitrogen and organic matter in the soil, when compared with cereal monocropping or cereal/fallow rotations. These changes improved soil physical properties and fertility, thereby increasing the productivity of cereals following legumes. These rotations also broke the disease and insect pest cycles that had built up in mono-cropping.
           Of course, identifying appropriate crop varieties with optimum physiology, morphology, and phenology to match local environmental conditions and, especially, the pattern of water availability is one of the important areas  of research within cropping systems management for improved water-use efficiency.
           ICARDA's recent success in rain-fed areas has been with 'Arta,' an improved barley landrace developed by the center from germplasm collected in Syria. Compared with most local landraces, 'Arta' averaged about 70% greater yield on-farm. Further drought-tolerant barley and wheat cultivars have been selected and are being tested under stress conditions in a number of CWANA and SSA countries.
          Lentil varieties better adapted to low rainfall areas       were adopted by farmers in Egypt where the lentil area declined steadily in the 1980s and 1990s until ICARDA developed new lines able to withstand drought stress more readily. In another collaboration with ICRISAT, ICARDA produced the first drought-tolerant kabuli chickpea lines for a Mediterranean environment.
When these and other lines emerge as varieties suitable for planting by farmers in combination with the various improved technologies to optimize soil water use, the scope for improving the livelihood of the farmers will be greatly increased.

Dr Christoph Studer is Plant Water Soil Specialist with ICARDA; Dr Mustafa Pala is Cropping Systems Agronomist; Niek van Duivenbooden is Land-Use Systems Specialist with ICRISAT in Niamey, Niger.

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