Abstract

LOSINNO, Beatriz N et al. Potential impact of irrigation with groundwater on soils of Pergamino stream basin, Buenos Aires Province, Argentina. Ecol. austral [online]. 2002, vol.12, n.1, pp.55-63. ISSN 1667-782X.

The analysis of the potential impact that complementary irrigation may have on salinization and sodification of soils is based on the knowledge of groundwater and soil background features. The objective of this work was to study the influence that electrical conductivity and depth of free groundwater may have on soil conductivity, and to perform a joint analysis of soil and water potentially used for irrigation to obtain the current situation in order to prevent soil degradation. Taking into account the spatial variability of aquifer properties shown in previous results, geostatistical methods were used to analyse the data resulting from soil and water sampling. A mapping of soil electrical conductivity was made using the kriging interpolation. Maximum values were found at the low topographic zones and some of them are in agreement with areas of high conductivity of free groundwater, at the left margin of Pergamino stream. Depth of the water table had a moderate negative geostatistical correlation with soil electrical conductivity only at the left margin, where a moderate correlation of soil and water electrical conductivity was also found. Electrical conductivity and exchangeable sodium percentage of soils were plotted against the conductivity and sodium adsorption relation of water from developing wells, respectively. A group of sites with moderate risk of salinization was determined, and 40% of the sites showed high risk of sodification. The influence of free groundwater on soils was not strictly associated with topography. The potential impact of complementary irrigation on soils was strongly dependent on the geographic location, and sites with a gentle topographical slope had higher risk of salinization and sodification.

Keywords : Aquifers; Degradation; Soil; Water quality.

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