Efeito residual do agregado siderúrgico e calcário no crescimento do eucalipto

Abstract

Metallurgical slags, consisting of calcium and magnesium silicate, is an alternative for the correction of Ca and Mg soil requirements. This study was done at Fazenda Floresta do Lobo - Uberlândia-MG, evaluating the effects of silicate on soil pH and residual contents of Si, Ca and Mg, and on DBH (diameter at breast height), quadratic diameter, basal area, CAG (current annual growth) and AAG (average annual growth) of eucalypts in comparison with liming. The experiment was done in a Typic Acrustox, on 30 November 2005, in a completely randomized design, as a 4 x 2 + 1 factorial with two acidity correction sources, four doses and an additional treatment (control, with no correctives) and five replications. Treatments referring to aggregate and lime doses were applied in the proportions of ¼, ½, 1 (1.5 t ha-1) and 2 time the corrective requirement. Soil pH was not affected by the corrective sources after four years and eight months. Soil calcium and magnesium contents depended on corrective source and dose applied. Corrective application affected silicon amount in the soil; however, no differences between the sources were observed. Quadratic diameter and basal area did not vary between the corrective sources after four years and eight months and five years and two months of application. Current annual growth was smaller than AAG at five years and two months, indicating that the eucalypts should be harvested. Soil corrective application in eucalypts resulted in greater AAG after four years and eight months and Five years and two months. Therefore, slags can be effectively used in eucalypts for supplying Si, Ca and Mg.