Zinc toxicity in millet grown in a Red Dystrophic Oxisol

Abstract

Zinc toxicity causes nutritional disorders specific for millet plants, damaging dry matter production. The objective of this experiment was to evaluate the effects of zinc application on millet dry matter growth, nutrition and production, grown under greenhouse conditions. The experiment was carried out in FCAV / UNESP in pots filled with a 3 dm³ sample of the superficial horizon of a medium textured Red Dystrophic Oxisol, during the period of October to December 2008. Six doses of zinc (0, 15, 30, 60, 120 and 360 mg dm^-3), in the form of zinc sulphate, were applied to the soil. The experiment was arranged in a completely randomized design with four replications. 45 days after emergence, the plants were cut and height, diameter of tillers, number of tillers, leaf area and mass and Zn content in shoot dry matter were evaluated. The use of high doses of zinc decreased millet growth and dry matter production, reaching Zn the toxicity levels in the shoots of 451 mg kg^-1.