EVALUATION OF PHONOLITE ROCK AS A POTASSIUM FERTILIZER ALTERNATIVE

In recent years, research has been conducted on the possible use of potassium silicates for the production and/or application as potash fertilizers, due to the increased Brazilian external dependence. The stonemeal is an alternative agriculture method that helps to restore and renew the soils poor fertilization of degraded areas through the incorporation of ground rock to the soil. In this context, the objective of this work is to evaluate the physical and chemical characteristics of the phonolite rock, from Pocos de Caldas plateau, MG, southern Minas Gerais, in Brazil, according to parameters for potash fertilizer, established by Ministry of Agriculture, Livestock and Supply. The phonolite in study has about 9% K2O and others nutrients which are also required by plants, such as Mn, Ca and Fe. The main mineral rock components were identified as: microcline and orthoclase, which confirm the primary mineralogy of the phonolite studied is feldspar minerals. Furthermore, IR and FRX analysis results corroborate the phases observed by XRD. Analysis of these results indicates that the phonolite rock has potential for application in agriculture as potassium alternative feedstock.