Foliar copper uptake by maize plants: effects on growth and yield

Abstract

A slight increase in the levels of a certain nutrient can cause a significant increase in crop yield or can cause phytotoxicity symptoms. Thus, the aim of this study was to evaluate the effect of foliar application of copper (Cu) on the growth and yield of DG-501 maize. The experiment was carried out between December 2009 and April 2010 in conventional tillage. When plants were with six to eight leaves, Cu (0, 100, 200, 300, 400, 500 and 600g ha-1) was applied to the leaves. Treatments were arranged in randomized complete block with five replications. When 50% of the plants were in flowering, it was evaluated the plant height, culm diameter, height of the first ear insertion, leaf area, and chlorophyll content. At harvest, it was evaluated diameter and length of the ear, yield and thousand grain weight. There was a linear reduction in the plant height and in the height of the first ear insertion with increasing Cu doses. On the other hand, chlorophyll content, leaf area, diameter and length of ear, thousand grain weight and yield increased at doses up to 100g ha-1 Cu, however, decreased at higher doses. Therefore, foliar Cu application at doses higher than 100g ha-1 has toxic effect in maize plants with losses in growth and yield.