David J. Lang1, Jeremy Duckworth2, David Russell2, John J. Read3, Joshua Andrew White1 and Rocky W. Lemus4, (1)Mississippi State University, Mississippi State, MS (2)Plant and Soil Sciences, Mississippi State University, Mississippi State, MS (3)Genetics and Precision Agriculture Research Unit, USDA-ARS, Mississippi State, MS (4)256 Dorman Hall, Mississippi State University, Mississpipi State, MS
White clover (Trifolium repens) var ‘Durana’ was oversown into established bermudagrass (Cynodon dactylon) in 2009. Soil analysis indicated potassium (K) was low and potash at 112 and 336 kg/ha was added as main plots. Nitrogen as ammonium nitrate or an ammonium sulfate/urea blend was added as 0, 34 and 67 kg N/ha in 2011 after each harvest (3x) and May and July in 2012 (2x). Clover stands were estimated by counting the presence or absence of clover within two 0.25 m2 quadrats divided into 16 equally spaced squares. The contribution of white clover in the sward was determined by separating hand clipped samples into clover, bermuda and other species on a dry weight basis. Plots (2x5 m) were harvested with a rotary or flail mower and grab samples were air-dried at 55 oC for 3 days to determine dry matter. Samples were ground to pass a 1 mm sieve and analyzed for protein by NIRS. Yield in 2011 with white clover as the N source was 8373 kg ha-1 compared with 9492 or 9908 kg ha-1 for 34 and 67 kg N ha-1, respectively or 88 to 85 % indicating that white clover can provide up to 100 kg N ha-1. Yield response to potash was minimal, but statistically significant (P<0.05). Ammonium sulfate/urea was also slightly more effective than ammonium nitrate in 2011 (P<0.05), but not in 2012. White clover provides a viable source of nitrogen that can reduce production costs.