Use of Ornamental Limestone Mining Tailings to Correction Soil Acidity and Plant Development

In the municipality of Nova Olinda - CE, the extraction of limestone for ornamental purposes, denominated Pedra Cariri, has been causing a series of environmental impacts due to the high generation and stock of tailings in the locality. The objective of this research was to verify the efficiency of this residue as a soil acidity broker and in the development of lettuce plants. The experiment was carried out in two stages: the first consisted of the incubation of 5 dm3 of soil in pots during three months, with doses of the powder from the Pedra Cariri tailing equivalent to 0%, 50%, 100% and 200% of the recommended dose for the elevation of soil base saturation to 60%, and a dose equivalent to 100% of the recommended dose, but using commercial calcitic limestone. The second stage of the experiment consisted in the cultivation of cv Lucy Brown lettuce in pots with soil previously corrected by liming. The powder from the Pedra Cariri tailing has potential to be commercialized as an agricultural input, because it caused elevation of the pH and Ca soil contents, reduction of exchangeable acidity, potential acidity and, consequently, decrease of aluminum saturation and increase of base saturation, not differing from the action of commercial calcitic limestone. The results of analyzes of lettuce development were not significant, where lettuce did not reach its productive potential. Nevertheless, the tailings powder had no toxic effects that would impair the development of the plant.