A Methodological Approach to Mapping Acid Sulfate Soils, the Spatial Variability of Acidity and Salinity, and Hazards at the Field Scale in a Sector of the Sinu River Floodplain, Colombia

摘要

There is currently no comprehensive acid sulfate soil (ASS) hazard mapping in Colombia. This study aims to create reliable prediction surfaces to estimate the types and subtypes of inland ASS, spatial variability of acidity and salinity, and acidification and salinization hazards. We used a combination of factor analysis, geostatistical tools with ordinary and indicator kriging, and Geographic Information System utilities to design a spatial prediction model. The studied variables were soil reaction, redox potential, and electrical conductivity at the A and B horizons obtained from a detailed systematic sampling in a sector of the Sinu River floodplain, Colombia. Two factors were identified; the first allowed us to delimit the homogeneous behavior of acidity as well as the types and subtypes of inland ASS precisely while the second facilitated the identification of ASS subtypes. Our findings indicate that 82% of the area reports very high and high to moderate acidification hazards in active ASS. A high salinization hazard exists in 26% of active ASS and 74% of both active and post-active ASS. These findings suggest serious acidification and salinization hazards and the need for urgent appropriate economic and environmental management. The approach applied here can be implemented at a field scale to improve understanding of the activity and behavior of ASS based on the acidity and salinity, which can facilitate a more reliable mapping of acidification and salinization hazards.