Variability and distribution of salinity and sodicity levels in fine-textured soils adjacent to brine shrimp farming in inland freshwater areas of Thailand

Abstract

Although several studies have focused on the relationship between brine shrimp farming and surface water contamination, much less is known about the effects of brine shrimp in inland freshwater areas on the vertical variability and distribution of soil salinity and sodicity levels. To provide a better understanding, fifty-eight soil samples in the areas adjacent to brine shrimp cultivation were collected at depths of 0-15, 15-30, 30-60, and 60-90 cm twice in August 2017 and February 2018 to determine soil salinity levels upon electrical conductivity (ECe), and soil sodicity levels upon sodium adsorption ratio (SAR). The spatial distribution of soil salinity and sodicity levels was estimated using inverse distance weighting (IDW) technique. The results revealed that soil ECe values at various depths collected from two periods varied from 0.18-13.63 dS m-1 ( x ˜ = 2.06 dS m-1). Spatial distribution of salinity levels based on IDW estimation exhibited similar patterns among soil depths in both August and February. These suggest no clear impacts of brine shrimp farming on vertical variability and spatial distribution of soil salinity levels in adjacent areas. Soil SAR values at various depths collected from two periods varied considerably, ranging from 4-69 ( x ˜ = 25), with the highest values at 0-15 cm depth. Spatially distributed patterns of SAR upon IDW appeared to display greater values in February than in August. These findings suggest explicit influences of brine shrimp aquaculture on vertical variability and spatial distribution of sodicity levels in fine-textured soils.