Rejeitos de mineradoras como substratos na produção de mudas de pinhão manso (Jatropha curcas L).

Abstract

In the semiarid region of Paraíba, one of the activities with the most economic value is mining, being examples of such activity the prospection of vermiculite and kaolin, which during the mining produce biologically negative tailings, which are accumulated in the courts, causing negative environmental impact.This study evaluates the growth of jatropha in substrates with tailings of kaolin and vermiculite. The treatments consisted of two substrates (soil and organic matter), two types of tailings (kaolin and vermiculite), five doses of tailings (0, 25, 50, 75 and 100%), with four replicates, comprising 80 vessels with a capacity of six liters. The analyzed variables were height, diameter, leaf number and dry leaf mass. After 4 months the plants were cut close to the substrate, separating the leaves, which were dried in an oven at 65°C for 24 hours and then weighed. The use of tailings, kaolin or vermiculite, at the dosage of 50%, principally with the addition of organic matter, proved to be more favorable to the production of dry leaf mass, height, diameter and to the number of leaves of Jatropha.