Assessment of deficit irrigation efficiency. Case study: Middle Sebou and Innaouene downstream

Abstract

Abstract Future projection shows that the availability of freshwater per capita will decrease to 560 m3/year by 2030 in Morocco. In this realm of adopting efficient irrigation, alternatives become a priority to overcome water shortage. The presented study aims to investigate theoretically the likelihood of improving irrigation efficiency at the plot level of the Middle Sebou and Innaouene downstream perimeter using 75% of the total irrigation water requirement (IWR), based on the successful results obtained by the Moroccan National Institute for Agronomic Research. The methodology consists of the extraction of monthly evaporation data from MODIS16A2 and process it under Google Earth Engine (GEE); data that are used in the second part of the study, which aims to assess the efficiency of deficit irrigation on a plot of 2,500 olive tree, using three main indexes; olive three height (cm), Stomatal conductance (mmol H2O m−2 s−1), and olive tree growth (cm). The results show that 0.75 of full irrigation could save 17% of the total water used, reducing the water irrigation supply by an average of 5 Mm3, with a slight decreasing of the olive production, estimated as 0.5 t/ha. Furthermore, water use efficiency and water productivity have been enhanced under deficit irrigation by respectively 0.25 kg/m3 and 0.54 Dh/m3. In economic terms, the result shows that with deficit irrigation, the decision-maker, or the farmer, could save about 5 million m3 per year, which is a boost to the global economy if the method is transposed and applied to other Moroccan regions and also a support for the new agricultural strategy called Generation Green.