Journal des sciences de la Terre et du changement climatique

Abstrait

Spatial and Temporal Zoning of Some Chemical Properties of Orumieh Lake Coastal Soils

Mohammad Hassan Biglouei  

In recent years, the effects of microgrids and wind erosion on the salt beds of Lake Urmia have affected its coastal lands. Therefore, the spatial and temporal zonation of some of the chemical properties of the coastal soils of the lake were determined in the Makookandi area, which is located in the WindRose direction of the lake. For this purpose, in September 2016 and June 2017, 36 soil samples were collected from 0 cm to 20 cm and 20 cm to 40 cm depths of the study area and then electrical conductivity of soil saturation extract (ECe), Total Dissolved Solids (TDS), acidity (pH) and Sodium Adsorption Ratio (SAR) all of them were determined. Land zoning maps were prepared based on ECe and SAR values using ArcMap software. The land zoning maps over the past two years have shown that ECe and SAR soils in the area have changed dramatically and their surface coverage has expanded. The highest values of ECe and SAR variations were observed in the proximity of the lake shore (boundary between land and dry lake bed). Six interpolation methods were used in the production of zoning maps and the conventional Kriging method was selected as the most appropriate method with the least amount of error compared to other methods. Also the results showed that the land area with ECe more than 20 dS/m in the layer of 20 cm to 40 cm and with SAR more than 93 mmol/l in the layer of zero to 20 cm of soil in 2017 compared to 2016 increased by 35.31% and 23.77%, respectively. Therefore, changes in the percentage of land area based on salinity and alkalinity of different soil layers in terms of temporal increase and spatial distribution were significant, which is a major threat to agricultural and environmental production