Options for improving irrigation water allocation and use : A case study in hari rod river basin, Afghanistan

Faisal Basiri Ahmad. 2009. Options for improving irrigation water allocation and use : A case study in hari rod river basin, Afghanistan. Bangkok : AIT, 97 p. Mémoire MSc : Water engineering and management : Asian Institute of Technology

Résumé : This study investigates cropping system options in context of irrigation water scarcity. It aims at improving irrigation water allocation with the objectives of maximizing net economic return and calories production, and minimizing selected production factors. CWR and IWR for all practiced crops are estimated for the case study area based on local climatic and cropping system information. Current field situation, as per farmers¿ practices and water availability, is quantified in terms of demand and supply, and compared with the actual crop water needs. Different scenarios are tested including different possible cropping systems under optimal and sub-optimal water supply. CROPWAT model was used for calculating CWR, IWR, and for developing irrigation scheduling, to quantify the yield reduction for the practiced crops during water shortages time. The gross irrigation requirement is calculated on the basis of different irrigation efficiencies with 10-day time step in the study area for all practiced crops. Results show that 10% improvement in irrigation efficiency will result in saving of average 21.4% gross irrigation requirement (GIR) for each practiced crop in the study area. Further, based on relative water supply (RWS) calculation, July, August, and September are the months during which crops are suffering from water shortage, with deficit amounting to 60, 70 and 50% respectively, compared to what is required. Simple optimization model is developed using linear programming with various constraints, to identify the cropping system options, through the maximization of net economic return (NER) and calorie production, and minimization of fertilizer and crop labor requirements. The results show that eliminating crops that consume more water and provide less economic and energy outputs is the most suitable option, and may highly improve over all benefits. Current farmers¿ strategy proves only suitable for maximizing calorie output. The overall finding of this study can be used to support the decision making and result demonstrate good guidelines for the planners; it can be helpful for farmer to take decision on adjustment of their cropping system according to their demand (Max NER, Max Cal). Study shows that deficit irrigation and area reduction are not the best options which are currently adopted by farmers based on lower NER, but to keep all crops with deficit irrigation shows a higher calorie output which, obviously help for food security. The study provides a good opinion of achieving higher NER, optimal irrigation supply for selective cropping system and less diversification with the limited water availability. Understanding of CWR, IWR, and the irrigation scheduling during the shortage months help farmers to take the right decision for preventing any yield reduction in their farm.

Mots-clés Agrovoc : irrigation

Mots-clés géographiques Agrovoc : Afghanistan

Classification Agris : F06 - Irrigation
P10 - Ressources en eau et leur gestion

Auteurs et affiliations

• Faisal Basiri Ahmad, AIT (THA)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/549843/)

Métriques

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