APPLICATION OF STEEL SLAG IN PASTURE OF Urochloa brizantha IN THE AMAZON

Abstract

Steel slag is a residue from the production of pig iron (steel industry), which has Si in its composition, in the form of calcium and magnesium silicate. It has the potential to correct soil acidity, and can also be used as a silicate fertilizer. The objective of this study is to evaluate the application of slag in Urochloa brizantha pasture at different doses and its effects on the plant. However, for the use of the different slags, they must initially be chemically characterized. Once the one with the greatest potential to be used as silicate fertilizer was chosen, a randomized block experimental design was established in the field, with four replications, and the treatments consisted of four doses of selected slag (0, 200, 400 and 600 kg ^ha-1). Subsequently, the morphophysiological responses were evaluated. The highest concentration of Si was found in blast furnace slag (atomic absorption spectrophotometer), which was used as silicate fertilizer. The application of the slag was manual and in cover after lowering the pasture. Before flowering, young and adult leaves were removed from the plots with and without the maximum dose. The samples were processed according to techniques for scanning electron microscopic analysis and spectroscopic microanalysis of x-rays by energy dispersion. The higher dose provided an increase in the number of siliceous bodies and the Si content in aculeiform tector trichomes in the leaf blade, as morphophysiological responses of the same in the face of the high availability of the element in the soil. The dose that provided the best performance was between 200 and 400 kg ^ha-1.