Phosphorus and sediment in runoff after core cultivation of creeping bentgrass and perennial ryegrass turfs

Limited research has been conducted on nutrient and sediment loss in runoff from mechanically disturbed turfgrass sites. This study assessed the effect of turfgrass species after core cultivation and fertilization on total dissolved P (as PO43-) loss and sediment transport. Six sloped (9-11%) plots (18.9 by 6.4 in or 121 m(2)) consisting of either creeping bentgrass (Agrostis palustris Huds.) or perennial ryegrass (Lolium perenne L.) were maintained as golf course fairways. Composite runoff samples were collected after simulated rainfall (152 mm h(-1)) and sediment yield was determined. Phosphate-P concentrations in runoff were equal to or lower than previously reported losses from turfgrass sites and were highest, 6 mg L-1, within 24 h after fertilizer application. The initially high PO43--P concentrations were temporary and decreased with time. Phosphate-P export was significantly higher for perennial ryegrass than creeping bentgrass on one occasion following fertilization and simulated rainfall. Sediment loading did not differ between turfgrass species and was considered low, never exceeding 0.35 kg ha(-1). As a consequence, the initially high but temporary PO43--P concentrations found in runoff, and the minimal erosion, should not be considered a serious threat to surface waters after core cultivation.