Effect of Sulfur Applications on Vaughn's #1 Bermudagrass Hay Yield and Forage Quality.

   Bermudagrass (Cynodon dactylon) has been a warm season grass hay of choice in coastal areas and western states for many livestock producers.  Yields are relatively high due to the large number of cuttings per season and quality is acceptable, even superior, if Bermudagrass is properly managed.  Vaughn’s #1 Bermudagrass® has been widely established becoming one of the leading varieties in the Middle Tennessee area.  This field study was conducted to evaluate Bermudagrass yield response to sulfur amendments and measure nutrient status of harvested forage.  Research was conducted two years on a Staser silt loam (Cumulic Hapludoll) on the Highland Rim approximately 30 miles north of Nashville (N 36° 28’ and W 86° 50’, elevation 217 m).  Experimental design was a randomized complete block of four replications.  All plots were treated with 127 kg P/ha^-1 as triple superphosphate, 372 kg K/ha^-1 as potassium chloride and 112 kg N/ha^-1 as ammonium nitrate according to soil test recommendations on low testing soils. Elemental S was applied at 22.4 and 44.8 kg S/ha^-1 respectfully.  K and S applications were once annually while N was applied after each cutting.  A Carter Forage Harvester was utilized harvesting 91 cm swaths through each plot where samples were weighed for dry matter and nutrient analysis.  Statistical analysis revealed there was no significant response in yield to S applications (P< 0.05).  There were no significant affects on nutritional quality measurements of NDF, ADF, P, K, Ca, Mg, Mn, Zn, S or TDN with the exception of copper (Cu), which showed a highly significant (P<0.01) decrease in levels as S rate increased.  Although plant S was not affected by treatments, sulfur was present in 78% of samples with amounts which were marginally antagonistic (>0.20 - 0.30 %) to copper metabolism in cattle.  Nitrate accumulation was not affected by S applications (P<0.05).