Evaluation of Irrigation Efficiency in the Boghol Valley, Rural Commune of Dabaga, Aïr Massif, Niger

The Aïr Massif is located in northern Niger. It is characterized by an arid climate that makes rain-fed agriculture impossible. To adapt, the population has developed irrigation from alluvial aquifers. The latter are dependent on rain and have a recurrent drying out. This results in the loss of crops or even abandonment of vegetable gardens leading to a subsequent decrease in production. In this context of aridity, the rational use of water is essential and necessarily involves knowledge of the water needs of crops and those delivered to these crops. The objective of this study is to assess the efficiency of irrigation water use in the Boghol Valley. The methodological approach is based on the calculation of water needs of crops using cropwat 8.0 software which required an inventory of soils, crops and areas they occupy according to the season. Then, the volume of water delivered at local scale was quantified using a volumetric meter. Finally, a comparison of the needs and quantities delivered at the valley level was made after extrapolation of data from the local scale. The results of the study show that irrigation is mainly carried out by gravity throughout the year. The quantities of water delivered are for all crops exceeding their needs. Overall irrigation efficiency of 71.07% was recorded. However, there are disparities with values of 80.75% and 49.70 % in the cold dry season and hot dry season respectively. This reflects considerable water losses in this arid environment. It is therefore necessary to improve efficiency by diagnosing irrigation practices.