Sustainable optimization of nitrogen uses in oat at sowing and top-dressing stages

Abstract

The most efficient nitrogen management by adjusting the nutrient dose at sowing and top-dressing with the supply period can increase the oat yield with greater sustainability. Considering the main cereal succession systems in Brazil and independent of the agricultural year condition, the objective of the study was to propose combination of nitrogen adjusted dose at sowing and at top-dressing with the most adequate moment of supply over the biomass and oat grain yield. The experiment was conducted in the years 2015, 2016 and 2017, in Augusto Pestana, RS, Brazil. The experimental plot was a randomized block design with four replicates, in a 4 x 4 factorial model, and four nitrogen rates at sowing (0 - control sample, 10, 30 and 60 kg ha-1), changing the top-dressing dose at total of 70 and 100 kg ha-1 in soybean / oat succession system and maize / oats, respectively. Expecting 4000 kg ha-1 of grain yield, with top-dressing supply in four periods (0, 10, 30 and 60 days after the emergency). The nitrogen management in oat, the combination of the adjusted dose at sowing and at top-dressing with the supply season shows the need to combine the technical recommendations of fertilization with the meteorological conditions of cropping. The absence of nitrogen at sowing and total dose applied at top-dressing, 30 to 35 days after emergence, increased the biomass and grains yield, regardless of condition of the agricultural year and succession system