Changes induced in the thermal properties of Galizian soils by the heating in laboratory conditions
The soil properties can be strongly affected by wildfires, causing direct effects on ecosystem productivity and sustainability. These effects depend, among other things, on the soil type and on the temperature reached during the fire. The variations of thermal properties of several Galizian soils heated in an oven in laboratory conditions at different temperatures (200–500 °C) during 15 min have been examined in this study. The measured properties are heat of combustion of soil organic matter, ignition temperature, specific heat and mass loss, determined using DSC 2920 TA Instruments and a TGA 7 Perkin Elmer under dry air gas flow. In agreement with other authors, this study establishes three temperature intervals with different effects on the soil: up to 200 °C, low intensity heating, with no significant changes in thermal properties; between 200 and 350 °C, medium intensity heating, with losses of organic matter up to 50%; and high intensity heating to temperature higher than 350 °C, with harmful effects on the soil organic matter. On the other hand and taking into account that the sampled soils had been affected by forest fires, the variations of thermal soil properties with the laboratory heating temperatures allowed for an estimation of the temperature reached by the soil in the real fire.
KeywordsForest fires Enthalpy of combustion Ignition temperature Maximum temperature Organic matter content Soil specific heat
- 1.MMA 2006. Los incendios forestales en España: 1996–2005.Google Scholar
- 2.Rodríguez Trejo DA. Incendios forestales. Mundi-Prensa México; 1996.Google Scholar
- 3.Porrero Rodríguez MA. Incendios forestales. Investigación de causas, Mundi-Prensa Madrid; 2001.Google Scholar
- 10.Solari P, Siccardi F. Soil degradation and erosion in small Mediterranean watersheds: non-lineal interaction between forest fires and extreme rainfall processes. In: Proceedings of III International Conference on Forest Fire Research, vol. II, Luso, Portugal; 1998. p. 1333.Google Scholar
- 11.Carballas M, Acea MJ, Cabaneiro A, Trasar MC, Villar MC, Díaz-Raviña M, Fernández I, Prieto A, Saa A, Vázquez FJ, Zëhner R, Carballas T. Organic matter, nitrogen, phosphorus and microbial population evolution in forest humiferous acid soils after wildfires. In: Trabaud L, Prodon P, editors. Fire in Mediterranean ecosystems. Commission of the European Countries, Ecosystems Research Series, Report 5. Brussels, Belgium; 1994. p. 379–85.Google Scholar
- 14.Chandler C, Cheney P, Thomas P, Trabaud L, Williams D. Fire in forestry. Forest fire management and organizations. New York: Wiley; 1991.Google Scholar
- 23.Lu L, Qin Z, Zhao C, Li W, Gao M. Effects of vegetation indices to the spatial changes of desert environment using EOS/MODIS data: a case study of Sangong inland arid ecosystem. Proc SPIE. 2006. doi:10.1117/12.689413.
- 24.Guitián Ojea F, Carballas Fernández T. Técnicas de Análisis de Suelos. Ed. Pico Sacro. Santiago de Compostela, Spain; 1976.Google Scholar
- 25.Dodd JW, Tonge K. Thermal methods. Chaps 2 and 4. London: Wiley-Interscience; 1987.Google Scholar
- 27.Giovannini G, Luchesi S, Giachetti M. Beneficial and detrimental effects of heating on soil quality. In: Fire in ecosystem dynamics: Mediterranean and northern perspectives. Proceedings of the Third International Symposium on Fire Ecology, Freiburg. The Hague, Netherlands: Academic Publishing; 1990.Google Scholar