Productivity and quality of tropical grasses under nitrogen application at the end of the rainy season

Abstract

The present study was carried out at the Department of Animal Husbandry of the Escola Superior de Agricultura de Lavras, Minas Gerais State, Brazil, in a Dark-Red Latosol. The experiment started on February 1, 1991 and was accomplished on May 29, 1991. The objective was to evaluate the dry matter yield, crude protein yield and fibre (neutral detergente) content in transvala grass (Digitaria decumbens Stent cv. Transvala), swazi grass (Digitaria swazilandensis Stent) and coast-cross (Cynodon dactylon L. Pers. Cv. Coastal x C. nlemfuensis Vanderyst var. robustus) under four different levels of N application (0, 100, 200 and 400 kg/ha N as ammonium sulphate). The N fertilizer increased dry matter production, crude protein and fibre of the grasses although the concentration of fibre was more affected by the time of harvest than by the N level. For all parameters studied, application of 100 kg/ha N showed the highest utilization efficiency and apparent recovery of the applied N. Coast-cross also proved to be the best grass concerning dry matter, protein yield and fibre and in response to N applied, while swazi grass was slightly superior than transvala-grass.