ESPACIALIZAÇÃO DE ATRIBUTOS QUÍMICOS E DO TEOR DE ARGILA E SUAS RELAÇÕES COM AS CURVAS ESPECTRAIS EM ÁREA DE LATOSSOLO BRUNO

Abstract

The soil has a natural variability in their chemical and physical attributes as well as generated by its management and agricultural and environmental importance increasingly perceive this variability and know how to handle. To achieve this, different strategies can be used to generate maps attributes and use the spectral response of soil to verify this variation. Thus, the objective of this study was to evaluate the spatial distribution of soil chemical properties and clay content in Oxisol area in Guarapuava-PR and its influence on the spectral curves. The study was conducted in Guarapuava, PR by collecting soil samples from depths of 0-20 and 20-40 cm in a gride 50x50 m. Following the soil samples were dried, ground, sieved through a 2 mm mesh for carrying out chemical, grain size and spectral readings analysis. After obtaining the analytical and spectral data they were correlated with their geographical coordinates and separated into classes for each chemical attributes to be evaluated. Subsequently, the maps of the chemical attributes and soil clay by the inverse distance method (IDW) and the average spectral curves as a function of the predefined classes were generated. The soil chemical properties showed high variability in both sampled soil layers, the higher phosphorus variability attributes, potassium and aluminum saturation. All samples showed values greater than 25 g dm-3 for the organic matter, but there was a low variability for this attribute and for the clay content and pH. Higher levels of organic matter and clay provide lower reflectance intensity throughout the electromagnetic spectrum. For chemical attributes, base saturation has greater intensity with higher levels in the range of 350 - 1350 nm while the calcium content demonstrates an effect only in the 1950 nm with higher reflectance at lower nutrient.