Efecto de la fertilización nitrogenada en el crecimiento de cinco pastos perennes en Ecuador.

Objective: To evaluate the effect of nitrogen fertilization on the growth and crude protein content of five perennial pastures of Ecuador. Materials and Methods: To evaluate the effect of nitrogen fertilization on the growth and crude protein content of the species Lolium perenne L. var. Alto, Lolium perenne x Lolium multiflorum var. Shogun, Festuca arundinacea Schreb var. Alta Barolex, Dactylis glomerata L. var. Quick Draw and Festuca arundinacea x Lolium multiflorum var. Premium, six progressive doses of nitrogen were applied (0, 70, 140, 210, 280 and 350 kg N ha-1 year-1). A split-plot design was used, where the species was placed in the large plot, and the nitrogen doses, in the small ones, with three repetitions. The variables biomass production, crude protein and normalized differential vegetation index, were evaluated. The data were analyzed through the statistical program INFOSTAT®. Results: The biomass production indicated statistically significant differences (p < 0,05) for the studied factors species and nitrogen doses, but not for the interaction of such factors. D. glomerata and F. arundinacea showed the lowest biomass production values (2 457 and 2 490 kg DM ha-1), compared with L. perenne, which had a moderate yield. F. arundinacea x L. multiflorum and L. perenne x L. multiflorum reached the highest biomass values (3 407 and 3 364 kg DM ha-1). The crude protein content also increased with the nitrogen doses. In turn, the normalized differential vegetation index increased, also according to a quadratic model, with a different response among species. Conclusions: All the species responded positively to the nitrogen application doses. It was determined that there is increase in the biomass production, crude protein content and normalized differential vegetation index. [ABSTRACT FROM AUTHOR]