Nutrients and sediment in runoff from creeping bentgrass and perennial ryegrass turfs

Although scientists have found little transport of nutrients to date in runoff from turfgrasses, more research is needed on a wider range of soil conditions and management scenarios. This study was designed to assess nutrient and sediment transport from creeping bentgrass (Agrostis palustris Huds.) and perennial ryegrass (Lolium perenne L.) turfs and to assess the influence that vertical mowing had on sediment transport. Sloped plots of bentgrass and ryegrass, maintained similar to a golf fairway, were irrigated to force runoff for the generation of runoff and leachate water samples. About 12 h before each runoff event, irrigation was used to equilibrate soil moisture for all plots. For four events, plots were treated with fertilizer at a rate of 4.9 g N m(-2), 0.3 g P m(-2), and 4.1 g K m(-2) about 4 h after pre-event irrigation and 8 h before runoff. For another four events, plots were verticut 6 h before runoff. Water samples were analyzed for NO3-N, total Kjeldahl-N (TKN), phosphate, and sediment. Mean NO3-N concentrations rarely exceeded 1 mg L-1. Phosphate and TKN concentrations and losses significantly increased when runoff was forced 8 h after fertilization. On average for these events, 11% of applied P and 2% applied N was detected in runoff and 14% applied P and 3% applied N was detected in leachate. For all other events, nutrient concentrations and losses were consistently lower. Vertical mowing had little affect on sediment transport, Sediment transport from both turfs averaged 0.8 kg ha(-1). On golf fairways, off-site movement of nutrients may happen if runoff occurs soon after granular fertilizer is applied to a nearly saturated soil.