REMOTE SENSING APPROACHES TO ANALYZE THE RELATIONSHIP BETWEEN SOIL PHOSPHORUS STOCKS AND MINERALOGY: A CASE STUDY

Phosphate fertilizers have a positive impact on crop productivity, particularly in tropical and humid subtropical soils. The dependence on phosphate fertilizers in these regions is mainly due to the interaction between phosphorus (P) and minerals hematite, goethite and gibbsite, abundant under these conditions. In this way, this study aims to analyze the presence of P as a function of each one of these mineral abundance in soils. Phosphorus stock and abundance of soil's mineral components data were obtained by digital soil mapping (DSM), soil spectroscopy was employed to evaluate the mineral abundance estimate and machine learning algorithm to predict the interaction. Although total phosphorus (TP) showed a stronger relation with hematite, the spatial distribution patterns between P and hematite, goethite and gibbsite were similar due to the oxides high capacity to adsorb P. Greater AP levels were found in agriculture areas, as a result of phosphate fertilizer usage.