Benchmarking for performance assessment of small and large irrigation schemes along the Senegal Valley in Mauritania

► Yield and technical efficiency are extremely variable in Mauritania. ► Large schemes do not perform worse than small schemes. ► Small schemes show greater variability and margin for improvement. ► Data envelopment analysis identified reference schemes for each inefficient scheme. Degradation of irrigation schemes, low and variable land productivity, and inefficient use of production inputs are major concerns in Mauritania. That prompted this benchmarking analysis of 17 small and 3 large irrigation schemes located along the River Senegal. The objectives were to establish benchmarks for both productivity and performance of irrigation schemes along the valley, and to inquire whether small schemes function better than large schemes. Cluster and data envelopment analyses enabled, respectively, grouping and ranking of irrigation schemes according to a set of pre-determined performance indicators: viz. energy costs, relative irrigation supply, irrigation intensity related to irrigable and equipped area, adequacy, and land productivity. Land productivity, which was highly variable, was compared to simulated land productivity for non-limiting conditions in order to determine yield gap variations. Few early sown crops were close to the simulated yield frontier of 10.6tha−1 and the mean yield was similar for large and small schemes (3.50tha−1 and 3.77tha−1, respectively). The analysis of the indicators revealed that, on average, large schemes performed similarly to small-scale schemes, but small schemes were more variable, particularly in input-use efficiency. Analysis of clusters identified three groups of irrigation schemes: viz. consuming and productive, precarious, and productive and economic. According to data envelopment analysis, four irrigation schemes were identified as technically efficient. Their average land productivity was relatively high (4.75tha−1) and energy costs were contained (59€ha−1). Data envelopment analysis also identified the particular efficient schemes that should be taken as reference for improvement of each inefficient scheme.