113-8 Nitrogen Dynamics in Bahiagrass-Rhizoma Peanut Mixtures in Contrast with Their Monocultures.

See more from this Division: C06 Forage and Grazinglands
See more from this Session: Forage and Grazinglands Oral I

Monday, November 7, 2016: 3:30 PM
Phoenix Convention Center North, Room 225 A

Erick Rodrigo da Silva Santos1, Jose Carlos Batista Dubeux Jr.1, Cheryl Mackowiak2, Jennifer Shirley2, Ann Blount3, Lynn E. Sollenberger4, Nicolas DiLorenzo1 and Rodrigo C Menezes5, (1)North Florida Research and Education Center, University of Florida, Marianna, FL
(2)North Florida Research and Education Center, University of Florida, Quincy, FL
(3)North Florida Research and Education Center, North Florida Research & Education Center, Marianna, FL
(4)Agronomy Department, University of Florida, Gainesville, FL
(5)Animal Science, Federal University of Viçosa, Viçosa - MG, Brazil
Abstract:
Nitrogen fertilization is an important management practice to increase forage growth. Cost and environmental impacts of N fertilizer, however, may reduce its use. In this study, we evaluated biological N2-fixation (BNF), % of nitrogen derived from the atmosphere (%Ndfa), and N losses (NH3 and NO3-) to the environment for mixtures and monocultures of bahiagrass (Paspalum notatum Flüggé) and rhizoma peanut (RP; Arachis glabrata Benth.). Treatments consisted of two bahiagrass entries (‘Argentine’ and an experimental entry; DF9), which received 90 kg N ha-1 after each harvest, two RP entries (Ecoturf and an experimental entry; Q6B), and the mixture of each bahiagrass with each RP. Plots were harvested every 6 wk. Nitrate concentration in leachate did not differ among treatments (P > 0.05), averaging 0.09 mg L-1. Loss due to NH3 volatilization for bahiagrass plots was greater compared with the mixtures and RP monocultures (P < 0.05), with no differences among grasses (P > 0.05). Ammonia volatilization for DF9 and Argentine was 0.170 and 0.136 kg N ha-1 d-1, respectively, while the means for the mixtures and RP monocultures were 0.016 and 0.020 kg of N ha-1 d-1, respectively. The %Ndfa for Q6B increased when mixed with Argentine (92.5%), and differed (P < 0.05) from its monoculture (78%) and the association with DF9 (76%). Ecoturf %Ndfa did not differ among treatments (P > 0.05) and averaged 87%. The BNF contributed more to biomass production in the monocultures when accounting the rhizoma peanut portion of the stand (P < 0.05). Ecoturf and Q6B fixed 39 and 43 kg N ha-1 harvest-1, respectively, while their corresponding mixtures fixed 17 and 21 kg N ha-1 harvest-1. Mixtures of bahiagrass-RP required less external input of N fertilizer, leading to lower N losses to the environment while providing similar or greater amounts of forage than fertilized bahiagrass.

See more from this Division: C06 Forage and Grazinglands
See more from this Session: Forage and Grazinglands Oral I