Soil thermal, physical, and chemical responses to low-rank coal amendment in saline-sodic conditions: biomass outcomes

Soil salinization is a major constraint to agricultural productivity in the Caribbean region of Colombia. Low-rank coals (LRC), characterized by their high humic acid content, have been proposed as amendments capable of improving the physical and chemical conditions of degraded soils; however, their influence on soil thermal conductivity, a key property governing heat flow, soil microclimate, and plant performance, remains poorly understood. This study assessed the thermal, physical, and chemical responses of saline-sodic soils in Cesar following LRC application. A field experiment was conducted using three LRC application rates: 0, 2, and 4 t ha⁻¹. Measurements included thermal conductivity, soil physical and chemical properties, and plant biomass. Based on the results, LRC significantly decreased soil thermal conductivity by 36%, from 1.25 to 0.60 W m-1 K-1 (P