An Introduction to Agricultural Water Accounting by Estimating Crop Water Consumption

Abstract

"Water accounting" is an approach to organise the information on water supply and analyse its socio-economic values in different sectors of the country. The estimation of the volume of water required for the national agricultural productions in the framework of product-based water accounting can be investigated. The key question is: what is the share of water consumption for the production of main crops in the country? In this study, using the net crop water requirement database of 2014-2015, and assuming an irrigation application efficiency of 44.7%, the water consumption of the selected crops in the country was estimated. Results show the maximum volume of water consumption by main crops is 78.6 billion m3, where 16.9 m3 is allocated to wheat production including 18.3% of the total water consumption for crops in the country. Comparing the net water consumption of wheat with other crops over 620 plains indicates that wheat, after barley, has the lowest net water consumption equal to 3562 m3/ha. Therefore, the volume of water consumption for wheat production is mainly affected by the cultivation area of irrigated wheat in the country (2.4 million hectares). Improving water productivity reduces the volume of water consumption in main crop production. The socio-economic values of main crop production could take precedence over its costs.

Keywords

• water accounting
• virtual water
• strategic products
• net irrigation requirement
• water consumption