Assessing the Water Productivity of Durum Wheat in Tunisian Semi-Arid Conditions

In semi-arid Mediterranean countries where crop yield is primarily water-limited, the topic of increasing productivity and water use efficiency is of great concern. The focus on water productivity of main crops is an imperative imposed by the critical situation of water resources as well as an ever-growing demand. However, there are still some gaps with respect to crop water use efficiency and productivity. The scope of this report is to establish the state of knowledge on water use efficiency and to help identify the possible margins of progress in terms of water productivity of wheat conducted in rainfed and irrigated conditions. Moreover, the inter relationship between crop yield, water use and water use efficiency were determined for Durum Wheat grown in Tunisian semi-arid conditions. The relationships have important implications for achieving efficient use of water resources in water-scarce areas. The methodology was mainly based on long-term simulations using the STICS crop model. The simulations were performed assuming a long-term weather database and representative soil types of the study area, chosen on the basis of their available soil water in the root zone. The analysis suggested that, under limited water resource conditions, full supplemental irrigation should be replaced with a level of deficit irrigation that should maximize water use efficiency.