IRRIGATION WATER QUALITY IN ALENTEJO (PORTUGAL) STUDY OF THE IRRIGATION PERIMETER OF THE RESERVOIR OF ROXO

The aim of this study was evaluate the quality of water resulting from the monitoring carried out during 2014/2015 in the hydraulic system and in the drainage network of the irrigation perimeter of Roxo's reservoir to be made a more sustainable management of irrigated area. The main conclusions were as follows: i) the water of the irrigation channel and drainage network show a mild to moderate degree of salinity risk; ii) doesn't show characteristics to modify the soil infiltration conditions; iii) indicates degree of restriction slight to moderate due to the amounts of Na+ and Cl-; iv) the drainage network presents toxicity due the chlorides and boron; v) the ammonia nitrogen and nitrate values were low. [...]we must keep in mind the decline and the collapse of many irrigation perimeters along the history resulting in the loss of the cultures production and in an increasing regional desertification so difficult to stop and to invert (Oliveira, 2012; Annetta and Colonna, 2004). In the origin of this situation are several ways of soil degradation and specially those related to the irrigation water quality deterioration (Oliveira, 2012). The aim of this study was: i) to evaluate the quality of water resulting from the monitoring carried out during 2014/2015 in Roxo hydro-agricultural holding (irrigation channel and drainage network); ii) to constitute a database for further comparison with the water quality resulting from the mixture after the connection to the Alqueva Multipurpose Project (AMP) in order to provide the implantation and maintenance of irrigation cultures...