Investigation and mapping of risk areas for harmful boron content and the relationship to salt and sodium content in soils of Soke Plain, Aydin, Turkey

Abstract

In the Great Meandros Basin, the boron content of irrigation water is considerable, up to 21.1 mg L⁻¹. This results in boron accumulation in soils of Soke Plain over an area of ∼25 000 ha. This study aimed to determine soil boron levels and map risk areas in Soke Plain for boron content. Large-scale soil maps were used. Soil sampling points were determined by visual interpretation of LANDSAT5-TM satellite views. One hundred soil samples were taken from a depth of 0–30 cm. Analysis showed that soil boron content ranged between 1.92 and 31.04 mg kg⁻¹. Soil boron contents were interpolated to create risk distribution maps for soil boron levels in Soke Plain. Furthermore, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite views were used to monitor restrictions in plant growth due to the high boron contents. A geographic information system (GIS) database of the area was established. Ninety-six percent of the study area had high to toxic boron levels. Positive correlations between soil boron content and salt and sodium contents indicate that soil management needs to consider the strong influence of the Mediterranean climate and irrigation water quality on the decline in soil fertility due to high soil boron content.

Keywords:

• boron toxicity
• boron risk mapping
• geographic information system