Chemical and Mineralogical Characterization and Soil Reactivity of Brazilian Waste Limestones

This paper evaluated four waste limestones mined in the Minas Gerais State, Brazil, and its potential as soil acidity amendments and its effects upon soil fertility attributes. Laboratory and greenhouse experiments were performed at the University Centre of Formiga (UNIFOR), with Oxisols collected under native conditions. A randomly experimental design was set with four replications, five liming materials (four waste limestones products + a mix pure product, to comparison) applied in two liming rates (50% and 70% of base saturation), and a control plot (no lime applied). Each liming material was characterized with respect to CaO(%), MgO(%), and micronutrients Ca, Mg, Fe, Cu, Mn, Zn contents by atomic absorption spectrophotometer and the mineralogy by X-ray diffractometry. Results indicated that all liming materials tested could be classified as supplemental source of calcium and magnesium and caused an increase in soil pH, soil Ca and Mg, and base saturation levels, whereas aluminum saturation decreased. Dolomite, calcite and quartz are major minerals. Cu, Fe, Mn, and Zn were found in trace-amounts in all waste limestones, which was considered typical for such products. Considering the improvement of chemical characteristics and increase soil fertility, the use of waste limestone is an alternative that allows the use of commercial discarded material in small properties.