The effect of volcanic ashes of Cordon Caulle on soil physical quality parameters in agricultural soils of southern Chile

Abstract

Chile is exposed to the constant activity of their volcanoes, which during the eruptions released ashes that had formed soils of south-central Chile (Andisols) during the holocene. The last June of 2011, Cordon Caulle volcano recorded eruptive activity, releasing a great quantity of volcanic materials that were deposited on soils under different land uses, generating environmental problems and uncertainties among farmers for its handling. The aim of this study was to evaluate the effect of the incorporation of these ashes on some physical quality indicators in 6 soil series of southern Chile (five Andisols and one Ultisol). For this, mixes of soil/ashes were used (regarding loads of 0, 5 and 10 cm of ashes height) to assemble soil cores of 230 cm³. The organic matter content (MO), particle density (Dr), soil texture, pF curve and air conductivity (kl) were determined. As ashes concentration increased, the sand content increased and, the clay and organic matter contents decreased, inducing an increase in soil particle density. The plant available water increased with the ashes incorporation, which is related to the associated textural changes. kl increased in all soil series due to incorporation of volcanic ashes, with the exception of the Cudico Series, which suggest the analyses of the effect of wetting and drying cycles on soil structure after the incorporation of volcanic ashes.