engleski

Soil salinity risk assessment in the lowland Neretva river valley

Soil salinization caused by natural or human- induced processes is a worldwide environmental hazard impacting more than 100 countries. In Europe this problem is most pronounced in the Mediterranean basin region including the costal region of Croatia where seawater intrudes through porous media into calcareous aquifers and salinizes both ground and surface water. This is especially evident in the Neretva River Valley, important agricultural region for citrus and leafy vegetable production which is becoming more affected by periodical or occasional soil and water salinization. The research was carried out in floodplain of the Neretva River Valley in the Mediterranean part of Croatia (43°00ʹN, 17°30ʹE) covering 5, 216 ha of agricultural land. The topsoil samples were taken using regular rectangular grid with a 500-m distance between the points, and from boreholes with a 1, 000-m distance between the points. A probabilistic approach, based on multivariate geostatistics was used to model the spatial variation of soil salinization risk at the landscape scale and to delineate the areas at high risk.The method requires indicator coding, which transforms measured data values into a binary variable according to critical thresholds. These latter were set to: 2 dS m−1 for ECe and 350 mg l-1 for Cl-. To determine the probability of exceeding these critical values. Factorial kriging was also applied to identify one regionalized factor that summarizes the effects of the selected variables on soil salinization. Maps of each soil indicator and regionalized factor were produced to show the areas at risk of salinization. The results are valuable for planning the management of salinity. The result considering land resources surveys showed that the degree of salinisation is strongly related to characteristics of the soils and their location in the catchments area. Salinity of soils within the root zone can be highly variable and in order to estimate the risk of salinisation it is important to examine soil salinity as a function of depth.

soil salinity; risk assessment; soil degradation; soil quality; mapping

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