Evaluación de la calidad del agua freática para su uso en riego mediante los índices ras, salinidad y de restricción de uso en la zona de san José de Poaló

Abstract

The Llanganates National Park is presented as an area that stores water bodies for agricultural use by the community of Sam Jose de Poaló. For this reason, the present investigation analysed the quality of water for irrigation, using the Sodium Absorption Ratio (RAS) index as the leading indicator and thus determine whether or not it is suitable for crop irrigation, taking as a reference the national environmental regulations and international regulations such as FAO, belonging to the United Nations Organization for Food and Agriculture and Riverside Standards. A simple and compound-type sampling for water was carried out in 7 strategic points, four at groundwater levels within the Llanganates National Park and three at surface levels in the agricultural sector of the community. Subsequently, analyses of physical parameters (pH, OD, T ⁰, Ce, groundwater levels), cations (K, Mg, Al, Na, Ca), anions (SO₃, P0₄, N0₃), and salinity indices. All the water parameters complied with the national regulations and, to a large extent, with the recommendations of the FAO, except for the anion levels. According to the Unified Text of Secondary Environmental Legislation, in Annex V of the Ecuadorian environmental regulations, the water had moderate-severe restrictions since it presented a salinity risk due to the low level of conductivity. Regarding the classification of the FAO, the water presents a moderate restriction since the water is suitable with precautions for irrigation. This area presents variations in precipitation and has a higher flow, which contributes significantly to the reduction of conductivity and sodium concentration. Therefore, dissemination to farmers and competent authorities is recommended to carry out semi-annual analyses prior to use in irrigation.