Effect of Nitrogen Rates on the Forage Yield of Maize Genotypes under Superadhesion

Maize production is directly linked to the genetic potential of the variety and management practices, among them, sowing density and soil fertility. The objective of this work was to analyze the effect of the application of nitrogen doses and its efficiency and use in maize genotypes grown under over - densification conditions, in the city of Rio Largo, Alagoas. The experiment was carried out from November 2015 to March 2016, and a randomized complete block design was used in the 3 x 4 factorial scheme (three maize genotypes: Branca, Viçosense and Nordestino, and four nitrogen doses: 80, 160, 240 and 320 kg ha-¹) with three replications, at seeding density of 167 thousand plants per hectare. The dry matter production of the forage and its qualitative characteristics were evaluated: dry matter, mineral matter, crude protein, neutral detergent fiber, acid detergent fiber and hemicellulose. Under the conditions of over-counting, it is concluded: (a) the corn genotypes Viçosense, Branca and Nordestino, for the productive and qualitative characteristics of the forage, presented similar and satisfactory behavior, except for the variable HC, where the genotype Branca stood out in relation to the others, presenting the highest levels of hemicelluloses, which gives it the highest concentrations of energy and digestibility of its forage; (b) the dose 80 kg ha-¹ of nitrogen was the most satisfactory for the productive and qualitative characteristics of maize fodder, since its effect was similar to increasing nitrogen dosages, in addition to providing a higher percentage of NDF.