Forage Yield and Nutritive Value of Warm Season Perennial Introduced Grass Cultivars Under Different Nitrogen Rates.

One school of thought is that if a variety produces more grass under high yielding conditions (high fertility) then it will also produce relatively more grass under low fertility conditions.  The other opinion is that under low fertility conditions, varieties with higher genetic yield potential offer no yield benefit.  The main question being, if a producer isn’t going to fertilize for high yields, is it valuable for the individual to use a variety with greater genetic yield potential. The Objective of this study is to determine relative yield and nutritive differences between bermudagrass varieties at different levels of nitrogen fertilizer input.  The experiment was initiated at the Pasture demonstration farm, Ardmore, OK in 2007. Five nitrogen (N) rates from 0 to 300 lb N/ac as ammonium nitrate will be applied in April, up to 150 lb N/ac.  Treatments receiving greater than 150 lb N/ac total will be split applied with up to 150 lb applied in April and 75 lb N applied after each harvest.   The design will be a randomized complete block with three replications.  Plots are mowed regularly during the establishment season and then harvested three to four times annually in succeeding years.  Forage is clipped using a rotary mower and dried to measure total dry matter yield.  Forage samples are analyzed for crude protein and TDN.  Analysis of variance and single degree of freedom contrasts are evaluated using SAS.