Affiliation:
1. Federal Institute of Education, Sciences and Technology Baiano, Campus Uruçuca, Uruçuca 45680000, Brazil
2. Department of Animal Science, Universidade Federal da Bahia, Salvador 40170110, Brazil
3. Campus of Itapetinga, State University of Southwest Bahia, Itapetinga 45700000, Brazil
Abstract
Nitrogen (N) is a nutrient used worldwide in pasture fertilization. However, it is a very volatile element. Furthermore, inappropriate use promotes environmental pollution and economic losses. The present study was carried out to evaluate the effects of the N source on the productivity and N utilization efficiency in Xaraés grass (Brachiaria brizantha cv. Xaraés) under tropical conditions. The randomized complete block design was used in a 3 × 2 × 4 factorial scheme: three seasons (rainy, dry, and transition), two N sources (fast-release = conventional urea, and slow-release = treated urea), and four N doses (0, 80, 160, and 240 kg N/ha/year). Forage accumulation per day differed (p < 0.0001) with the season and N dose. The interaction between those showed a positive linear effect (p < 0.0001) during the rainy season and transition. With increasing N doses, there was a linear increase in annual dry matter production and N accumulation. However, the N utilization efficiency (p < 0.0001) was reduced. Nitrogen sources did not affect forage accumulation and N utilization efficiency. Therefore, it is not recommended to replace fast-release nitrogen fertilization (conventional urea source) with a urease inhibitor (slow-release N source), promoting benefits with lower production costs.