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Seeding Rate Effects On Nitrogen Replacement Value of White Clover in Tall Fescue.

Poster Number 709

Tuesday, November 5, 2013
Tampa Convention Center, East Hall, Third Floor

Kimberly A. Cassida1, Joseph J. Paling2, Richard Leep1 and Timothy S. Dietz3, (1)Michigan State University, East Lansing, MI
(2)Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI
(3)Channel Bio Corp, Williamston, MI
Binary mixtures of legumes and grass reduce dependence on purchased nitrogen fertilizer.  Legume proportions of 30-40% of the sward dry matter are believed necessary for optimum N replacement value (NRV), but it is not clear how legume and grass seeding rate relates to the botanical composition of the final mixture or its stability over time. We conducted a plot-scale replacement series experiment to evaluate performance of varying seeding rates of white clover (Trifolium repens L. cv. ‘Alice’) and a soft-leafed endophyte-free tall fescue (Schedonorus arundinaceus [Schreb.] Dumort. nom. cons. cv. ‘Bariane’) on a pasture site in mid-Michigan. Legume/grass plots were seeded in 2010 using clover:grass seed ratios of 0:100 (8 kg/ha clover), 25:75, 50:50, 75:25, and 100:0 (28 kg/ha fescue) of the monoculture rate by weight.  Monoculture plots of tall fescue were integrated into the trial and fertilized with 0, 50, 100, 150, 200, and 300 kg/ha of N to determine N response curve for calculation of N replacement value of clover. Plots were harvested three times each in 2011 and 2012. Cumulative tall fescue yield increased linearly by 7 and 24 kg/ha for each kg/ha of N applied in 2011 and 2012, respectively. Clover proportion was compared in the third cutting each year.  In 2011, clover percentage was 22.5 to 47.7% in mixtures, but mixtures did not yield more than grass monoculture (P > 0.05). In 2012, clover proportion in mixtures was greatly reduced and did not differ from grass monoculture (P > 0.05), but 50:50 and 0:75 seeding ratios yielded more forage than grass monoculture (P < 0.05).  Seeding 50 to 75% white clover with tall fescue was equivalent to as much as 107 kg of fertilizer N over time, but results were not consistent across years and may depend on death of clover.
See more from this Division: C06 Forage and Grazinglands
See more from this Session: General Forage and Grazinglands: II

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