Fontes e doses de zinco no feijoeiro cultivado em diferentes épocas de semeadura

This work was carried out with the objective of evaluating dry bean yield in different seasons, submitted to foliar application of different sources and doses of zinc. A randomized block design with four replications was used in a 3 x 2 x 5 factorial arrangement. The treatments were formed by the combination of three growing seasons ("fall/winter", "spring/summer" and "fall/summer" seasons), two zinc sources (zinc sulfate and zinc chloride) and five zinc doses (0, 100, 200, 400 and 800 g ha-1), divided into leaf sprayings at 25 and 35 days after emergence (DAE). For the winter crop, a greater increase was observed in grain yield, its main components (number of pods per plant and number of grains per plant) and leaf-zinc content, as compared to the other two seasons. There was no interaction between growing seasons, doses and sources of zinc. In soils with zinc content of 2.1 mg dm-3, the addition of this nutrient by foliar application did not result in increase of bean yield.