Herbage accumulation, canopy characteristics, and nutritive value of tropical grasses in the Amazon biome

Abstract

AbstractForage species diversification reduces risk associated with forage–livestock production. In the Amazon biome, an alternative is needed to ‘Marandu’ palisadegrass [Urochloa brizantha (Hochst. ex A. Rich.) R.D. Webster] because of Marandu death syndrome. Our objective was to compare herbage accumulation (HA), canopy characteristics, and nutritive value of Marandu with two alternative grasses, ‘Guará’ (Paspalum regnellii Mez) and ‘Tupi’ [Urochloa humidicola (Rendle) Morrone & Zuloaga]. During 2 yr, grasses were clipped to a 12‐cm stubble height every 28 (rainy season) or 42 d (dry season). Annual HA did not differ across years for Guará (13.7 Mg dry matter [DM] ha−1) and Tupi (12.2 Mg DM ha−1); however, Marandu HA was 30% less in the second than the first year. Marandu had greatest annual HA in the first year (15.5 Mg DM ha−1), and Guará was superior to the other grasses in the second year (13.5 Mg DM ha−1). Tupi had the least leaf proportion among grasses in both rainy and dry seasons, and its leaf proportion was greater in the dry than rainy season (715 vs. 610 g kg−1). Greatest stem proportion was observed in Tupi and the least stubble mass occurred in Guará (2000 kg DM ha−1). When differences in crude protein occurred, Tupi concentrations (80–130 g kg−1) were less than either Guará (97–157 g kg−1) or Marandu (81–139 g kg−1). Overall, Tupi and Guará HA and nutritive value support their recommendation as alternatives to Marandu monoculture in Amazon forage‐based livestock systems.