Forage productivity and morphogenesis of Trachypogon vestitus as affected by phosphate fertilization levels in the Roraima’s savannas

Abstract

The effects of phosphate fertilization (0, 40, 80 and 120 kg of P2O5 ha-1) on forage production and morphogenetic and structural characteristics of Trachypogon vestitus pastures were evaluated under natural field conditions in the savannas of Roraima. Phosphate fertilization positively and significantly (P<0.05) affected green dry matter (GDM) production, absolute growth rate (AGR), number of tillers plant-1, number of leaves tiller-1 (NLT), average leaf size (ALS), leaf tiller area (LTA), appearance rates (LAR), expansion (LER) and leaf senescence rates. The maximum yields of GDM, AGR, LAR, LER, NLT, LTA and ALS were obtained with the application of 109.2; 106.4; 56.1; 81.5; 97.4; 58.6 and 63.7 kg of P2O5 ha-1, respectively. The efficiency of P utilization was inversely proportional to the P doses applied.