Resíduo da mineração de calcário laminado na correção da acidez do solo e na nutrição do feijoeiro

Abstract

The laminated limestone belonging to the Membro Crato of the Formação Santana, which composes the stratigraphy of the Bacia do Araripe, is commercially known as Pedra Cariri and has been exploited for more than 70 years as ornamental rock. In Nova Olinda – CE, its exploitation has caused a series of environmental impacts due to the high generation and stock waste in the locality. The objective of this research was to evaluate the use of this residue to control soil acidity, thus, the effects of the residue application were evaluated on soil fertility, cowpea plant nutrition and grain yield. The experimental design was randomized blocks, with 4 treatments and 5 replicates. The treatments consisted: control without application of limestone (T1); 50% (T2), 100% (T3) and 200% (T4) of the recommended dose, to raise soil base saturation to 60%. The grounded rock (<0.177 mm) was incorporated in the 0,2 m soil layer and cowpea (Vigna unguiculata (L.) Walp), creole variety, was cultivated after the reaction of the residue in the soil. The rock residue was efficient in the correction of soil acidity, raising the pH to satisfactory levels and reducing the exchangeable acidity, potential acidity and saturation by aluminum, besides causing significant variations in the potassium, magnesium, sulfur, iron and manganese contents in the plant leaves. No toxicity or nutrient deficiency symptoms were observed in plants. There was no significant change in grain yield, but the values obtained were higher than those obtained with the same cultivar.