Características agronômicas da soja cultivada em solo de Cerrado com diferentes doses e épocas de aplicação de zinco

Abstract

The soybean is one of the most important crops worldwide. However, when grown in soils with nutrient deficiencies the productivity is significantly affected, and Zinc is a micronutrient that most limits the crops production in different regions of the world. Aiming to evaluate the effect of zinc doses and application times on the agronomic characteristics of soybean, an experiment was conducted in the city of Ipameri, Goiás – Brazil, in the season 2014/15. The experimental design was a randomized block with 10 treatments and four replications in a factorial 2 x 5, as follows: two zinc application times (stage V9 and R1) and five doses (0, 3, 6, 9 and 12 kg ha-1 of Zinc), and the source of zinc used was zinc sulfate (20% of Zn). The cultivar used was the M7739 IPRO. The Zn was applied on the soil surface and distributed at a distance of 0.1 m from the crop rows. We evaluated the following characteristics: leaf zinc content, Spad chlorophyll content, plant height, stem diameter, the first pod height, number of pods per plant, number of grains per pod, number of reproductive nodes per plant, weight of 100 grains, grain yield and physiological quality of seed. The results were submitted to analysis of variance and the means were compared by Tukey test, at 5% probability. To analyze the significant influence of doses of Zn on the characteristics evaluated, it worked with regression analyzes. The fertilization with Zn positively influenced the leaf Zn content, plant height, stem diameter, the first pod height, number of pods per plant, number of reproductive nodes per plant, weight of 100 grains and grain yield. The leaf Zn content, the weight of 100 grains and grain yield showed significant difference between application times, with superior results to the average V9. According to these results it is recommended to fertilization with Zn in soybean.