Bahiagrass Cultivar Response to Grazing Frequency with Limited Nitrogen Fertilization

Abstract

Warm-season grasses require N fertilization to achieve their full production potential; however, increased costs have limited the use of N by beef cattle (Bos spp.) producers. Th e objective of this study was to test the eff ects of two grazing frequencies (2 and 4 wk) on production, nutritive value, and persistence of 'Argentine' (tetraploid), 'Pensacola', 'Tift on 9', and 'UF Riata' (diploids) bahiagrass (Paspalum notatum Flügge) cultivars fertilized with 60 kg N ha -1 yr -1 . Th e study was conducted in Ona, FL, from January 2010 to December 2011. Treatments were eight factorial combinations of two grazing frequencies (2 and 4 wk) and four bahiagrass cultivars. Th e four cultivars were grazed by beef cows (505±30 kg) for approximately 8 h to a 7.5-cm stubble height at 2-or 4-wk intervals. Diploid cultivars had greater herbage accumulation (HA) in the spring; however, Argentine had greater annual HA in 2010 and 2011. Plots grazed at 4 wk had approximately 50% greater HA than 2-wk grazing frequency. Argentine and Pensacola had greater root and rhizome mass than Tift on 9 and UF Riata when grazed every 2 wk, while Argentine had greater cover than any of the diploids when grazed at the 2-wk frequency. Results show that Argentine is a productive and persistent bahiagrass for beef cattle producers using limited N fertilization and frequent grazing in Florida. Decreasing grazing frequency is an eff ective management practice to increase bahiagrass HA and persistence, particular the upright-growing Tift on 9 and UF Riata.

Resilience in Forage and Grazinglands

“…However, focus of selection on herbage accumulation and nutritive value may have altered plant morphology, physiology, and preference by animals, which may negatively affect persistence. Vendramini et al (2013) tested the effects of grazing frequency on bahiagrass ( Paspalum notatum Fluegge) cultivars under a limited N fertilization regime (Table 2). ‘UF Riata’, an upright‐growing cultivar, had reduced root‐rhizome mass and ground cover when grazed at 2‐ compared with 4‐wk intervals.…”

“…Root-rhizome mass of bahiagrass (Paspalum notatum Flueggé) cultivars grazed at 2-or 4-wk grazing frequency. Adapted fromVendramini et al (2013).…”

Herbage Responses and Biological N2 Fixation of Bahiagrass and Rhizoma Peanut Monocultures Compared with their Binary Mixtures

“…The total N aboveground (TNAG) was obtained by multiplying the N concentration by the HA of each component, where TNAG B was the TNAG in bahiagrass and TNAG RP was the TNAG in RP. Argentine has been reported as one of the most productive bahiagrass cultivars (Vendramini et al, 2013), and because DF9 is a dwarf entry that has a shorter growth (turf type), Argentine was able to out yield DF9 in 2016. Biological N 2 fixation was determined by using the natural abundance technique (Freitas et al, 2010).…”

“…In the middle season of 2016, Argentine + 90 kg N ha −1 harvest −1 had HA of 3120 kg DM ha −1 and did not differ from DF9 + 90 kg N ha −1 harvest −1 (1350 kg DM ha −1 ), RP monocultures (1550 and 1630 kg DM ha −1 for Ecoturf and Q6B, respectively), and the mixture Q6B-DF9 (1350 kg DM ha −1 ). Argentine has been reported as one of the most productive bahiagrass cultivars (Vendramini et al, 2013), and because DF9 is a dwarf entry that has a shorter growth (turf type), Argentine was able to out yield DF9 in 2016. In a cowork developed simultaneously in the same plots, Argentine and DF9 presented the same amount of belowground biomass (roots and rhizomes) for both years (Santos et al, 2018), indicating that the difference in biomass between both entries occurred only in the aboveground portion.…”

Emissão de CO2, características do dossel e acúmulo de forragem em pastos de capim-pensacola sob frequências de desfolhação

“…Trabalho semelhante a esse foi realizado em Ona, Flórida, Estados Unidos, onde foram avaliadas características dos pastos de diferentes cultivares de Paspalum. Do total de parcelas, cinco eram desfolhadas a cada duas semanas e cinco desfolhadas a cada quatro semanas, com auxílio de roçadeira costal, com corte de toda forragem acima da altura de resíduo de 7,0 cm (2) . Na determinação da altura média do dossel, foram realizadas cinco medições ao acaso por parcela com auxílio de régua com graduação em centímetros.…”