Herbage Yield of Irrigated and Non-Irrigated Brachiaria and Bermudagrass Genotypes.

Marandu palisadegrass is the most widely planted grass for forage production in Brazil. Cultivar improvement has resulted in new hybrid genotypes which combine characteristics that could improve productive potential and adaptation. The objective of this trial was to evaluate forage production and herbage accumulation of Mulato II brachiariagrass (CIAT hybrid 36087), Marandu palisadegrass and Tifton 85 bermudagrass 85 in response to clipping frequencies, with or without irrigation (two trials) from 22 Sept. 2011 through 23 Feb. 2012.  The experimental design in both trials was a randomized complete block factorial (3 x 2), corresponding to the combinations between the three genotypes and two clipping frequencies (28 and 42 days of regrowth), with four replications. Mulato II had a higher total forage production (18.4 Mg DM ha^-1), followed by Marandu (16.9 Mg DM ha^-1) and Tifton 85 (17.0 Mg DM ha^-1) regardless of defoliation frequency. With longer harvest intervals (42d) there was a 50% increase in herbage yield, compared with the shorter interval (21 and 13.8 Mg DM ha^-1). In general, irrigation increased total forage production, from 16.8 to 18.0 Mg DM ha^-1. Irrigation increased herbage accumulation rate from 108 to 125 kg DM ha^-1 d^-1. Within trials, there was no difference in herbage accumulation rate among the cultivars and clipping frequencies, ranging from 113 and 120 kg DM ha^-1 d^-1.