Coffee plantation soil characterization using a multi-method approach near the Volcano Nevado del Ruiz, Colombian Central Cordillera/Caracterizacion de suelos cercanos al Volcan Nevado del Ruiz, Cordillera Central de Colombia, con tecnicas multiherramientas

The presence of iron oxides may provide a sensitive indicator of the effects of cropping practices on coffee plantations. Authors characterized the mineral phases present in soil A horizons at three different farms located in the Department of Tolima within the regions of Libano and Villahermosa. Our analysis includes X-ray diffraction, Mossbauer spectroscopy, and remote sensing to discriminate the distribution of the different magnetic mineral phases. X-ray diffraction was used to identify the mineralogical properties of iron oxide such as hematite, goethite, and ferrihydrite (Fh), as well as tectosilicate minerals such as albite and sanidine. Mossbauer spectroscopy results for samples taken at room temperature indicate the presence of [Fe.sup.2+] and [Fe.sup.3+] mineral phases, which possibly correspond to ilmenite or magnetite. Finally, Sentinel-2A multi-spectral imager (MSI) data was used to map the distribution of iron oxides and study the influence of their distribution throughout the study area. A high correlation between Mossbauer spectroscopy and Sentinel-2A MSI data exists throughout the study area. The results suggest that farms close to the main Nevado del Ruiz Volcano have a more significant mineralogical variability. In contrast, more distant farms are characterized by soils with more iron oxides, the product of weathering, erosion, and human activities. Keywords: iron oxide; magnetic soil; Mossbauer spectroscopy; X-ray diffraction; Sentinel-2; La identification de oxidos de hierro puede proporcionar un indicador sensible para determinar los efectos de diferentes practicas de cultivos en plantaciones de cafe. Por tal razon, en la presente investigation se analiza el suelo de tres fincas ubicadas en el Departamento del Tolima. Se caracterizaron las fases minerales con hierro a lo largo de la capa productiva (horizonte A) de los suelos en las regiones de El Libano y Villahermosa. Se utilizo difraccion de rayos X, espectroscopia de Mossbauer y teledeteccion para discriminar la distribution de las diferentes fases minerales magneticas. La difraccion de rayos X se utilizo para identificar las propiedades mineralogicas del oxido de hierro como la hematita, la goethita y la ferrihidrita (Fh), ademas de los minerales tectosilicatos como la albita y la sanidina. Los resultados de la espectroscopia de Mossbauer para muestras tomadas a temperatura ambiente indicaron la presencia de fases minerales de [Fe.sup.2+] y [Fe.sup.3+], que posiblemente correspon