Sulfur Level and Timing Effects on Agrostis Palustris Injury and Soil pH

Putting greens in the U.S. are sometimes constructed with calcareous sands having CaCO₃ levels >1% and pH values near 8.0. Golf course superintendents may attempt to reduce pH by applying elemental sulfur or using an acidifying N fertilizer, such as ammonium sulfate. Our objectives were to evaluate the influence of sulfur (S) level (122, 244, 488, or 976 kg ha⁻¹ yr⁻¹) and timing (1, 2, or 5 applications yr⁻¹), and the use of ammonium sulfate as a N source, on soil pH and creeping bentgrass (Agrostis palustris Huds.) injury on a calcareous sand. Treatments were applied for two consecutive years on a green containing 84% sand, 14% silt, and 2% clay, with a pH of 7.7 and 1.5% CaCO3. Neither S level nor ammonium sulfate reduced pH the first or second year when soil was sampled at 0 to 7 cm, or in the second year when soil was tested incrementally at depths of 0 to 1 cm, 1 to 4 cm, or 4 to 7 cm depths. Bentgrass injury occurred only when S was applied at 976 kg ha⁻¹ yr⁻¹. Injury was generally greatest when S was applied in one application, and decreased as the total S level was split into 2 or 5 applications.