Adubação nitrogenada em cobertura no desenvolvimento e produtividade do milho QPM

Abstract

The maize QPM (Quality Protein Maize) are corns with improved protein quality, with about 50% more of lysine and tryptophan levels than the common corn, which are essential in human and animal diet. The corn crop demand large amounts of nitrogen and often is the nutrient that most limits the grain yield. With the aim to evaluate the development and production of the variety BR 473 of QPM maize submitted to different nitrogen levels in coverage, two experiments were conducted at the Fazenda Experimental de Ciências Agrárias da Universidade Federal da Grande Dourados – UFGD, (Experimental Farm of the Faculty of Agrarian Sciences of the Federal University of Grande Dourados – UFGD), located in Dourados - MS, the first being deployed in the second crop of 2015 and the second experiment in the summer of 2015/2016. The experimental design for both experiments was a randomized complete block design with five treatments and four replications. The treatments were five N rates (0, 30, 60, 90 and 120 kg ha-1) applied in bands on stage v4 using urea as source of N. The evaluated agronomic characteristics were plant height, ear insertion height, stem diameter, ear length, ear diameter, number of grains per head, productivity, thousand grain weight, leaf nitrogen content and protein content in the grains. Nitrogen fertilization in the second season 2015 influenced the characteristics: plant height, leaf nitrogen content and protein content in the grains and for the summer crop responds positively to the plant height, ear insertion height, number of grains per head, productivity and leaf nitrogen content. The highest yields were obtained in the summer season, with 120 kg ha-1 of N applied in coverage.