The study of Water Productivity and Yield Gap of Wheat, Barley and Maize in Qazvin Province

Determination of water productivity gap is very important for planning and accomplishing water productivity improvement and strategies. This study has been carried out in Qazvin province based on GYGA protocols, which is an international methodology in yield gap analysis. Water and crop data gathering, climate and soil classification with GIS and crop modeling with Aqua Crop model version 5 were used for this purpose. Yield gap of wheat, barley and maize were determined to be 5.4, 5.5 and 6.7 ton/ha, respectively. Also, water productivity gap of wheat, barley and maize was 0.82, 0.47 and 1.22 kg/m3, respectively. The Yield gap and water productivity gap were varied in different climate zones and water productivity was varied in different years. The mean relative water productivity index (the ratio of current to potential water productivity) for wheat, barley and maize were estimated 0.38, 0.54 and 0.39%, respectively. From this viewpoint, barely crop has had better status among the proposed crops. The high water productivity gaps between the current and potential water productivity show that there are considerable weak points in agricultural production and irrigation management. In addition, there are high opportunities for enhancing water productivity and food security and decreasing pressure on water resources.