Suchergebnisse

The objective of this study was to evaluate the biomass production of elephant grass and leucaena in Paraná state, Brazil, for the generation of renewable energy. Two field studies were conducted in the municipality of Ibiporã (23° S, 51° 01?W). In the first study, the dry matter accumulation curves were calculated, with sampling at 30, 60, 90, 120, and 180 days after cultivation. The second study was conducted in a randomized complete block design with split plots. The total aboveground biomass production of elephant grass and leucaena was estimated in the main plot. Cutting times of 60 and 120 days after cultivation were evaluated in the subplots. The productivity of dry matter (kg.ha-1) was estimated using the biomass data. In addition, the potential production of energy from the burning of elephant grass biomass, and the potential production of total aboveground biomass and energy of elephant grass (in Paraná) was estimated using an agrometeorological model. Elephant grass can be potentially used as an alternative energy source. Leucaena has slow initial growth, and it must therefore be evaluated over a longer period in order to determine its potential. Simulation analyses of the capability of power generation, conducted based on the annual dry matter production, revealed that elephant grass could be an important source of renewable energy in the state of Paraná.

The objective was to evaluate the productivity, chemical composition, ruminal degradability of dry matter and digestibility of BRS capiaçu grass (Pennisetum purpureum Schum.) managed at five regrowth ages. A completely randomized design with ten replications was used in the BRS capiaçu elephant grass subjected to five cutting intervals (30, 60, 90, 120 and 150 days) in the summer, making a total of 50 plots with a useful area of 4 x 2 m. There were daily increases in the dry matter production in the order of 382 kg ha-1, with 49,859 kg ha-1 being produced at 150 regrowth days. The dry matter content and organic matter linearly increased (P < 0.01) at different regrowth ages. The crude protein content, in vitro dry matter digestibility and in vitro digestibility of neutral detergent fiber linearly reduced (P < 0.01) 0.037%, 0.196% and 0.256% per day, respectively. Potential degradability of dry matter decreased from 68.9% at 30 days to 44.7% at 150 regrowth days (0.194 percentage units per day). The rate of degradation of fraction B 'c' was not modified (P = 0.94), averaging 1.46% hour-1. In the cultivation of BRS capiaçu elephant grass in the summer season, in the northern region of Minas Gerais, the age for harvesting between 90 and 120 days of regrowth is recommended.