MECAR - Metodologia para a estimativa de água de rega em Portugal | MECAR - Methodology to estimate the irrigation water consumption in Portugal

Under the European system of agri-environmental indicators, the Council of the European Union recognized the need for comparable data on agricultural activities, especially with regard to farm management practices and use of agricultural inputs, including the use of irrigation water, having been enshrined this principle in the Regulation (EC) 1166/2008. To meet this legal requirement, established a partnership between the INE and ISA / CENTROP to develop the MECAR - Methodology for Estimating Irrigation Water in Portugal. After the comparative approach of different methodologies, it was considered that the use of estimation models based on water balance would be the best approach to achieve these objectives. The methodology was based on soil water balance, which is done by the mathematical model ISAREG (Teixeira and Pereira, 1992 and Teixeira, 1994), which is based on the procedure of the FAO (Doorenbos and Pruit, 1977 and Doorenbos and Kassam, 1979) determining the water requirements of crops, which apply correction factors for loss of efficiency that stem from the characteristics of irrigation systems used and the conditions of irrigation, particularly in their management of their respective owners. The validation of results produced by MECAR, to prove that the volumes obtained by simulation were located close to the actual values, it was considered satisfactory. However, it is recommended that a second validation be performed, comparing the annual simulated data recorded by the irrigation farmers associations and individual farmers for the same period. The application of MECAR to actual data from IE 2007 is an operational test of this solution is adequate as it allowed to obtain reliable information and consistent with the requirements of the regulation.