Efficient management of water resources is especially important in the dry areas of CWANA, where water scarcity is severe. ICARDA's research has recently demonstrated that supplemental irrigation at sowing can considerably increase wheat grain yield. Even greater gains can be made if deficit supplemental irrigation is applied as the crop grows. This gives a maximum grain yield only slightly lower than that obtained by full supplemental irrigation, while simultaneously allowing a larger area of land to be irrigated with the same volume of water.

Improving wheat production through supplemental irrigation in Central Anatolia, Turkey

Since 1998, ICARDA has been conducting joint trials at the Ankara Research Institute for Rural Services. These four-year trials follow-up earlier joint modeling work, which indicated that supplemental irrigation has the potential to greatly benefit central Anatolia's highland agro-ecology. The results of the more recent trials show that limited supplemental irrigation may double rainfed wheat's grain yield.

much more in the following spring than plants which germinate later. In most years, the first rainfalls sufficient to germinate the seeds occur later than October, the optimal emergence date. Because of this, unirrigated wheat plant stands are small when the first frost stops their growth in early December. In the trials, supplemental irrigation at sowing allowed wheat plants to emerge early and stand for the optimal time before they were subjected to the frosts of early winter. This allowed the maximum yield to be achieved.
     The trials also revealed that supplemental irrigation given later in the spring and early summer further increased grain yield, but involved a lower rate of water-use efficiency. Applying enough water to fully satisfy the crop's requirements further increased the yield by1t/ha, to over 6.2 t/ha.
     However, applying deficit irrigation at the rate of one-third of the amount used in full irrigation (a water saving of 67%) reduced yield by less than 10%. This confirms the result of earlier research, conducted in Syria and already published by ICARDA, which showed that deficit supplemental irrigation is much more efficient in terms of water-use than full supplemental irrigation.
     Moreover, in areas where water resources are scarce and more limiting than land, the water saved as a result of deficit irrigation can be used to irrigate new lands (so increasing water productivity). Using this strategy, total farm production can be increased by over 30%, as was shown in farmers' fields in northern Syria. Adopting such a strategy can help farmers cope with increased water scarcity in the dry areas.