Produção e qualidade do sorgo forrageiro (Sorghum bicolor) sob adubação nitrogenada

Abstract

The Brazilian cattle fodder as food base is formed by several grass species. The main grasses that make up the feeding of dairy and beef cattle are the tropical grasses, due to its rapid growth under favorable conditions of temperature and soil moisture. The sorghum in Brazil fits well in various regions as summer planting, as in southern and central region. However, in the subtropical regions, sorghum for grazing should not be understood as the only forage solution for feeding livestock, but as a great alternative to be intercropped with other crops in the summer. This study aimed to evaluate the effect of nitrogen fertilization on yield and quality of forage sorghum in terms of grazing. The work was conducted at the experimental area of Universidade Tecnológica Federal do Paraná (UTFPR), Câmpus Dois Vizinhos. For the development of experiment was used the summer annual species forage sorghum cultivar Jumbo. The study was conducted during the period of November 2010 to April 2011. The experimental design was completely randomized blocks with three replications. The treatments consisted of the following N rates: 0, 37.5, 75, 150, 225, 300 and 375 kg ha-1. For the production of fodder, the dose of 272 kg N ha-1foi that had the highest dry matter yield of sorghum, with a proportional increase in forage quality in terms of PB. The increase of N doses reduced the NDF content of the plant. For macronutrients, the largest amount of N accumulated in the plant would be obtained with 330 kg N ha-1. For the match, the more it raises the nitrogen levels in soil, the greater the accumulated contents, since the potassium obtained the largest amount ccumulated in plantacom doses around 255 kg N ha-1. During the period of high temperatures in the Southwest region of Parana, the cultivation of sorghum when well managed and with proper fertilization, is an excellent alternative for use in cattle feed, due to its high DM production of good quality.