Crescimento e alocação de fitomassa de cinco gramíneas forrageiras em condições de cerrado

Abstract

Forage grasses are dominant species in Brazilian pastures, among which we can mention Brachiaria decumbens, B. brizantha cv. Marandu, Panicum maximum cv. Colonião, Tanzania, and Mombaça. The present study was carried out to better understand the growth of these forage species as well the partitioning of dry mass among the different organs of the canopy at different stages of their development. A completely randomized block design was used with five treatments and four repetitions. B. decumbens produced the highest number of tillers (NT). Mombaça produced the highest total dry mass (TDM) up to 55 days after emergence (DAE), but from 62 DAE on the productions of all the species did not differ statistically. Mombaça had the highest leaf area index (LAI). The allocation of phytomass incorporated as stem dry matter (SDM) was higher than that allocated to the production of dry matter of green leaves (DMGL), from 41 DAE for B. decumbens, P. maximum cv. Colonião and Tanzania, 55 DAE for cv. Mombaça, and 62 DAE for B. brizantha. The maximum instantaneous crop growth rates (CGR) were achieved at 62 DAE: B. decumbens - 37.1 g m-2 day-1, B. brizantha - 49.2 g m-2 day-1, P. maximum cv. Colonião - 54.7 g m-2 day-1, cv. Tanzania - 55.7 g m-2 day-1, cv. Mombaça - 45.4 g m-2 day-1.