Reflectance, emissivity and elevation data of the sensor ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer)/Terra were used to characterize soil composition variations according to the toposequence position. Normalized data of SWIR (shortwave infrared) reflectance and TIR (thermal infrared) emissivity, coupled to a soil-fraction image from a spectral mixture model, were evaluated to separate bare soils from nonphotosynthetic vegetation. Regression relationships of some soil properties with reflectance and emissivity data were then applied on the exposed soil pixels. The resulting […]

The aim of this study was to evaluate spectral curves of three different soils amended with organic residues derived from the cane sugar industry. It was used disturbed samples of four soils of distinct classes: a typic dystrophic Red Latosol (Haplustox-LVd), a typic dystroferric Latosol (Rhodic Ustox-LVdf), a typic dystrophic Argisoil (Rhodustults-PVd) and a Cambisol (Dystropept-CXa). They were amended with 0, 40 or 80 t ha-1 of organic residues derived from the cane sugar and alcohol industry (filter cake). Spectral reflectance of […]

The objective of this research was to determine a methodology for the use of spectral data obtained in the laboratory and from orbital images for the recognition and discrimination of three soil classes in the State of São Paulo, Brazil. Reflectance data were obtained by a spectroradiometer/by Landsat 5 images in the laboratory as standards from soil samples of Oxisol, Ultisol, and Entisol profiles. Orbital data were converted to reflectance and classified by the Spectral Angle Mapper. The spectral curves obtained […]

The objective of this work was to evaluate the efficiency of spectral reflectance in the detection of different erosion levels present in soils. Four soils, corresponding to a Red-Yellow Latosol (Oxisol), Latosolic Terra Roxa Estruturada (Ultisol), Cambisol (Inceptisol) and Vertisol, located in a toposequence in Piracicaba, São Paulo, Brazil, were evaluated for their chemical, physical and mineralogical attributes. The spectral reflectance was measured between 400 and 2,500 nm using an Infra Red Intelligent Spectroradiometer. Each soil was collected according to […]

The objective of this work was to study the spectral reflectance of a Brown Latosol (Haplohumox) and “Terra Bruna Estruturada” (Tropohumult) developed from volcanic acid rocks which occur in the center-south region of Paraná, Brazil. These soil samples were collected at depths of 0-20 and 40-60 cm. The characterization, discrimination and estimation of the soil attributes were studied by their reflected energy determined at the wavelength interval of 400 to 2.500 nm using an IRIS laboratory spectroradiometer. It was possible […]

The objective of this study was to study the effects of soil macrofauna on physical and chemical attributes and spectral reflectance of an Oxisol, Ultisol and Vertisol in Piracicaba (SP), Brazil. Along a topossequence, the soil aggregates produced by ants (Atta sp.), termites (Cornitermes cumulans) and earthworms (Pontoscolex corethrurus), were collected and compared with the control soil without recent visible animal activity. Soil chemical analysis and granulometry were carried out. The soil spectral behavior was determined in laboratory with a […]

This study was conducted in order to verify the influence of induced chemical properties in standard kaolinite and samples of three soils from the State of Paraná, Brazil – Hapludox Haplohumox and Tropohumults – on the spectral reflectance obtained in laboratory using a spectroradiometer, adjusted from 400 to 2500 nm. The samples were treated with solutions of calcium acetate, sodium acetate and incubated with calcium carbonate and sodium bicarbonate. Higher spectral reflectance was observed in the samples treated with calcium […]