The use of inorganic industrial sludge as a source of nutrients in growing media is a recent practice. The sludge produced by the zinc-galvanic industry has a high concentration of plant nutrients such as Zn, Fe and Ca that, depending on the doses used in soils and growing media, could be toxic to the plants. In the present experiment a commercial organic substrate was used by adding increasing doses of an industrial sludge produced by a zinc-galvanic industry. Doses of industrial sludge (0.0; 0.38; 0.75; 1.50; 3.0; 6.0; 9.0 and 12.0 g L-1 of the growing media) were applied to the chrysanthemum cv. Rage, cultivated in a greenhouse. After 12 weeks of cultivation, the following variables were measured: pH and electric condutivity of the substrate, Zn content of the shoot tissue and substrate, height (HGT), dry mass of the shoots (SDM), flowers (FDM) and roots (RDM). The addition of 0.38 g L-1 of industrial sludge caused a small increase in HGT, SDM, FDM and RDM. The industrial sludge can supply nutrients to the crop. In doses higher than 3 g L-1 occurred accentuated decreasing of shoot production occurred due to an unbalanced nutrition associated with Zn toxicity symptoms and high electric conductivity.
Dendranthema grandiflora; trace elements; phytoavailability; soil chemistry; toxicity; galvanoplasty
