Potencial forrageiro de gramíneas tropicais para a produção de pré-secado.

Abstract

The objective was to evaluate the agronomic characteristics, chemical composition and conservation in the form of predried tropical forage grasses. For evaluate the agronomic and chemical characteristics of the plant, six genotypes of tropical pasture grasses (Brachiaria brizantha genotypes Marandu and Xaraés, Panicum maximum genotypes Paredão and Massai and Andropogon gayanus genotypes Tupã and Planaltina) were used in two years of evaluation, whereas for the production of predried grasses were used in one year of evaluation. The agronomic characteristics evaluated were number of tillers, number of live leaves / tillers, plant height, canopy height, leaf area index, light interception, total green and dry mass production, and chemical composition for the two years of evaluation. For the predried, the chemical composition, gas analysis, AGV’s, aerobic stability and pH, ammoniacal nitrogen, losses and population of microorganisms were evaluated. There was an interaction (P <0.05) between genotypes and years of evaluation for the number of tillers, number of leaves and plant height. For light interception and leaf area index, there was an effect (P <0.01) isolated for the years and genotypes factors. A greater number of leaves / tiller was observed in the first year for the Xaraés and Tupã grasses. There was a significant effect for genotypes in relation to the CP content. Interaction was observed (P <0.01) for the levels of DM, PB and NDF in relation to genotypes and the years of evaluation. Greater losses were observed in the predrying process for the Planaltina genotype 8.2 ± 0.37%. There was a significant effect (P <0.01) for CO2, with the highest averages for the Massai, Marandu, Planaltina and Tupã genotypes. A significant effect was found for acetic, propionic and isobutyric acids (P <0.01). Data were submitted to ANOVA, for genotypes and years, which was using the ScottKnott test (P <0.05) . For microorganisms, descriptive data analysis was performed. The Paredão genotype has higher plant height, forage canopy and MSFT production. The genotypes of the species B. brizantha and P. maximum have better predried characteristics, and their production can be recommended.