Response of Bahiagrass Cultivars to Nitrogen Fertilization and Cutting Frequency.

There are approximately 365,650 hectares of bahiagrass in Mississippi in which 27% are in hay production.  A major expense maintaining hay production is annual nitrogen fertilization.  The study was initiated to compare biomass production and nutritive value of two bahiagrass cultivars under nitrogen fertilization and cutting frequencies.  A three-year research study was conducted at the Henry H. Leveck research farm at Mississippi State University on a Marietta sandy loam (Fine-loamy, siliceous, active, thermic Fluvaquentic Eutrudepts).  The experimental design was a 2x3x2 factorial in a split-split plot arrangement replicated four times.  The main plot was the bahiagrass cultivars (‘Pensacola’ and ‘Tifton 9’), the subplot was the nitrogen fertilizer rates (0, 112 and 224 kg N/ha/yr) and sub-subplot was the cutting intervals (4 or 6 weeks). The treatments included two bahiagrass varieties (‘Pensacola’ and ‘Tifton 9’), three nitrogen rates and two harvest regimes (4 and 6 weeks).  Nitrogen was applied using urea-ammonium sulfate (33-0-0-18S) in equal split applications at greenup, and after the first, second and third harvest.  There were a total of four yield harvests each season.  Results reported include dry matter yield for each harvest, total dry matter yield, and nutritive value.  Data was analyzed using repeated measures in PROC GLM of SAS and means were separated by the Least Significant Difference (LSD) values were used for mean separation to determine treatment differences at a significance level of α = 0.05.  There was no seasonal yield differences among the bahiagrass cultivars.  Seasonal yields were influenced each year by N rate and harvest frequency.  Seasonal yields increase 28 and 64% with applications of 112 and 224 kg/ha/yr, respectively.  Harvest date yields were influenced by N rate within each year.  Change in nutritive values were impacted by cutting frequency within each season.