Canopy characteristics of ‘Mavuno’ hybrid brachiariagrass and ‘Marandu’ palisadegrass harvested at different harvest intensities

Abstract

‘Mavuno’ is a newly released brachiariagrass (Urochloa hybrid) cultivar with limited information available in the literature. The objective of this study was to compare forage characteristics of this cultivar and ‘Marandu’ palisadegrass [Urochloa brizantha (Hochst. ex A. Rich.) R.D. Webster cv. Marandu] harvested at 2 different stubble heights during 2 growing seasons (January‒April). The study was conducted in Araguaína, TO, Brazil in 2017 and 2018. Treatments were the factorial arrangement of 2 brachiariagrass cultivars, Mavuno and Marandu, harvested at 2 harvest intensities, 5 and 15 cm stubble height, distributed in a randomized complete block design with 4 replicates. Response variables were canopy height, forage accumulation, proportion of leaf, stem and dead material, and concentration of crude protein (CP) and in vitro digestible organic matter (IVDOM). Mavuno and Marandu did not differ (P>0.05) in forage accumulation (mean = 3,800 kg DM/ha/harvest) and IVDOM concentration (mean = 637 g/kg); however, Mavuno had lower CP concentration (101 vs. 110 g/kg), greater proportion of stems (16 vs. 13%) and less dead material (4 vs. 6%) than Marandu (P<0.05). Harvesting at 5 cm stubble height rather than 15 cm increased herbage accumulation per harvest (4,100 vs. 3,500 kg DM/ha) with decreased proportion of leaves (77 vs. 84%) and CP concentration (101 vs. 115 g/kg) (P<0.05). Our data suggest that Mavuno is a useful addition to the range of brachiaria grass cultivars for sowing in tropical regions and further studies are needed to evaluate the long-term persistence of Mavuno under different management practices in a range of environmental situations. While harvesting at 5 cm stubble height rather than 15 cm increased forage accumulation but reduced CP concentration, regardless of cultivar, longer-term effects on the stability of these pastures with these harvest frequencies and heights are open to question and studies should be continued for longer periods to assess longevity of stands under the 2 management strategies. Applying maintenance fertilizer during the growing season might have prevented the marked decline in dry matter accumulation as the season advanced and this hypothesis should be tested.