Response of Tifton 85 to Enhanced-Efficiency Nitrogen Fertilizers and Different Supply Strategies in Tropical Conditions.

Response of tifton 85 to enhanced-efficiency nitrogen fertilizers and different supply strategies in tropical conditions Bernardo Melo Montes Nogueira Borges; Saulo Strazeio Cardoso; Edimar Rodrigues Soares; Ederlon Flavio da Veiga Moline; Fabio Teixeira Lucas; Marco Antonio Ribeiro Filho; Fernanda Ribeiro Peixoto; Barbara de Brito Brunozzi; Edson Luiz Mendes Coutinho Nitrogen is the nutrient that promotes the greater increase in forage yield, though it is important to handle it correctly due to its losses in tropical soils by volatilization and leaching. The enhanced-efficiency fertilizers scenario is promising, yet studies in tropical conditions are important to understand how these products are going to respond. The experiment was designed to determine the effectiveness of Tifton 85 production of dry matter and N uptake using different nitrogen sources and supply strategies in a Typic Eutrustox under tropical conditions. Nitrogen was applied at 400 kg of N ha-1 year-1 in two different supply strategies using the total rate at the begin of the experiment and using half at the beginning and the other half after the second cutting. Six N sources were used Kimcoat N®, Producote 39® (1,5-2 months), Producote 38® (3-4months) and Producote 37® (5-6months), Super N® (urease inhibitor NBPT) and urea. A control treatment was also applied using 100 kg of N ha-1 (urea) at every cutting. Tifton 85 was harvested every 30 days and sampled for total N analysis. The fertilizers efficiency varied according to the supply strategy applied. Where the application of the total rate led to a decrease of production and forage nitrogen content. The split application maintained yield and nitrogen content, always higher after every application. The fertilizers shown different efficiencies, in which Super N maintained a greater yield throughout the harvests.