Isotopic and Conventional Techniques to Improve the Irrigation Practice in Order to Enhance Agriculture Production under Water Limiting Conditions in Morocco

摘要

Sound and efficient irrigation practices are important for achieving sustainable management of water resources for agriculture in arid and semi-arid regions. An experiment was conducted to monitor seasonal water consumption of citrus plants irrigated bya drip irrigation system at the Agafay station in the middle of Morocco. For this purpose, an eddy-covariance (EC) system, a meteorological station and a fluxmeter were employed, as well as measurements of soil moisture and temperature which were made available continuously during the experimental period. The oxygen-18 stable isotope was used to partition evapotranspiration (ET) fluxes, i.e. a Keeling Plot with data from five layers inside a mandarin orchard being generated to assess ecosystem isotopicflux. The results suggest that loss by percolation constituted about 38 percent of the cumulative amounts of irrigation and rainfall. Partitioning of ET showed that transpiration dominated the evaporation during the two sampling days. This result confirms that the method of irrigation applied by the farmer was very appropriate for conditions in the orchard, but that it is necessary to re-examine both the amount and timing of water applied through irrigation to minimize losses by percolation.