Vol. 112 No. 1 (2018)
Research Papers

Water productivity analysis of sand dams irrigation farming in northern Ethiopia

Lorenzo Villani
Università degli Studi di Firenze, Firenze, Italy
Giulio Castelli
Department of Agricultural, Food and Forestry Systems (GESAAF), Università degli Studi di Firenze, Firenze, Italy
Eyasu Yazew Hagos
Institute for Water and Environment, Mekelle University, Mekelle, Ethiopia
Elena Bresci
Department of Agricultural, Food and Forestry Systems (GESAAF), Università degli Studi di Firenze, Firenze, Italy
1981: "camp of refugees from Ogaden (Ethiopia) in Ali Sabieh (Rep. of Djibouti)". Photo: A. Giordano
Published June 28, 2018
How to Cite
Villani, L., Castelli, G., Hagos, E. Y., & Bresci, E. (2018). Water productivity analysis of sand dams irrigation farming in northern Ethiopia. Journal of Agriculture and Environment for International Development (JAEID), 112(1), 139-160. https://doi.org/10.12895/jaeid.20181.726

Abstract

Water scarcity in drylands is the main problem that has to be tackled by farmers and practitioners that work in these areas. Climate change and increased and wealthier population are expected to put additional stress on the water resource. A large number of studies is calling to focus efforts to enhance water productivity (WP), and one of the most promising option is represented by water harvesting, the collection and storage of runoff water to be used for beneficially uses. Among the available technologies, sand dams are experiencing a renovated interest because of their relative simplicity and their potential. This research aims to deepen the knowledge about WP of water harvesting systems studying a sand dam irrigation system in Tigray, north Ethiopia, where farmers are getting used to this new technology. The research was carried out in the period March-April 2017, when farmers use sand dams water to irrigate off-season maize. We analysed a representative plot irrigated through a shallow well drilled in the sand dam aquifer, in terms of yield, Crop Water Productivity (CWP), Crop Water Productivity based on Evapotranspiration (CWP(ET)) and Economic Water Productivity (EWP), through field data analysis and a validated Aquacrop model. CWP(ET) was found to be low (1.12 kg of grain per m3 of evapotranspired water), due by both inefficient water application and low soil fertility. Aquacrop model results showed that changing the irrigation schedule can increase CWP(ET) up to 1.35 kg/m3 and EWP up to 3.94 birr/m3, but yield gap is mainly due to the low soil fertility. Interventions on soil fertility can raise yields from the original 3.3 up to 8.5 kg/ha, and thus CWP(ET) and EWP up to 2.94 kg/m3 and 9.54 birr/m3 respectively. To enhance the effect of sand dams in northern Ethiopia, a set of measures, including conservation agriculture, is then proposed.