70149 Forage Production and Nutritive Value of Annual Ryegrass and Small Grain-Annual Ryegrass Mixtures in South Florida.

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Sunday, February 5, 2012
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Reyna D. Hallworth1, Joao Vendramini1, J.D. Arthington1, Ann R. Blount2 and A.D. Aguiar1, (1)Range Cattle Research and Education Center, University of Florida, Ona, FL
(2)North Florida Research and Education Center, University of Florida, Marianna, FL
Two studies conducted from February through April, 2011in Ona, Florida evaluated herbage production and nutritive value of annual ryegrass varieties and annual ryegrass-small grain mixtures.  Experiment 1 tested six ryegrass varieties (RG; ‘Earlyploid’, ‘FLX2010 Red 4x’, ‘Gulf’, ‘Jumbo’, ‘Nelson’, and ‘Prine’) and experiment 2 tested annual ryegrass, annual ryegrass-triticale (RT, Triticosecale sp.), or annual ryegrass-rye (RR, Secale cereale L.); both were distributed in completely randomized designs with four replicates. Plots measuring 3 x 2 m were seeded on 19 November 2010 at 22, 112, and 134 kg ha-1 for annual ryegrass, ‘Trical 2700’ triticale, and ‘FL 401’, respectively.  Plots received 45 kg N ha-1, 20 kg P ha-1, and 38 kg K ha-1 on 17 December 2010 and 45 kg N ha-1 on 14 January 2011 and 1 March 2011. Plots were irrigated with 13 mm wk-1 through 10 December to assure establishment. A 3 x 0.5 m area was harvested at 5-cm stubble height every 28 d and analyzed using GLIMMIX for herbage mass accumulation (HMA), crude protein (CP), and in vitro organic matter digestibility (IVOMD), with the main effects of treatment, month, and the interaction.  In experiment 1, there was no difference in HMA (1074 kg ha-1), CP (166 g kg-1), or IVOMD (745g kg-1) among RG cultivars. Herbage accumulations were greatest in March, and least in Feb (1280, 1137, and 805 kg ha-1 for March, April, and February, respectively; P < 0.0001).  Crude protein was greater in April and March (180 g kg-1) than February (140 g kg-1; P < .0001).  Digestibility decreased over time (792, 745, and 697 g kg-1 for February, March, and April respectively; P < 0.01).  In experiment 2, the addition of a small grain did not affect HMA (1066 kg ha-1), CP (169 g kg-1) or IVOMD (753 g kg-1). Herbage accumulation was greater in February than March or April (1238 and 980 kg ha-1, respectively; P = 0.0003).  Crude protein was greater (P = 0.0395) in March (181 g kg-1) than February (161 g kg-1), while IVOMD was greater (P = 0.025) in February (771 g kg-1) than April (734 g kg-1).