Thermography to assess evaporative fluxes on organic amended water repellent soils

Abstract

Soil water repellency (SWR) is natural phenomenon occurring in soils throughout the world. It is a surface property associated with the organic composition in soils that reduces the affinity of soil for water. Its impact on ecosystems services are influenced at multiple temporal and spatial scales. Thermography shows promise to detect and track the temporal and spatial dynamics of soil water repellency. In lab experiments, it has been demonstrated that there was a huge potential for thermography in SWR mapping to detect high levels of soil water repellency. However, the technique has a number of limitations. One major drawback was its poor performance to detect low or subcritical levels of water repellency which is often present in the environment. Another issue is the induction of a temperature gradient to reveal SWR, which can change the repellent nature of soil and the evaporative fluxes from soil. The objective of this study is to improve characterization of soil water repellency by examining the change in evaporative fluxes in water repellent soils using thermography. The results from a field experiment with soils amended with organic waste material to increase the level of soil water repellency will be presented. The aim of this study is to distinguish the link between thermal regime, evaporative flux, soil water content and soil water repellency generated by the amendment. Through this approach, we will be able detect difference in evaporative fluxes under organic amended soils and determine the relationship with soil water repellency. This will improve the management of water and soil resources within water repellent soils by understating its effect on water dynamics.