Options for improving irrigation water allocation and use

This study investigates cropping system options in relation to irrigation water scarcity by improving water allocation in an attempt to maximize Net Economic Return (NER) and calorific production. Crop Water Requirement (CWR) and Irrigation Water Requirement (IWR) are estimated for common crops in a case study base in the Hari Rod river basin of Afghanisatn using the CROPWAT model. The current field situation considering water availability and farmer agricultural management practices is quantified in term of demand and supply of water, and compared to actual crop water requirement. Furthermore a simple optimization model is developed using linear programming to identify the cropping system options, through the maximization of NER and calorific production. Findings indicate that planting the full range of common crops with deficit irrigation result in high calorific production. However, restricting crops to those that are more water demanding significantly increases the Net Economic Return.