NUTRIENT AND SEDIMENT LOSSES FROM TURFGRASS

The contribution of turfgrass fertilizer to surface and groundwater pollution is not well documented. Two studies, at separate locations, were therefore initiated to examine losses of nutrients and sediment via leaching and runoff from turfgrass. Treatments included fertilizer applied in a liquid and granular form and an unfertilized control. Sodded tall fescue (Festuca arundinacea Schreb.)/Kentucky bluegrass (Poa pratensis L.) plots were fertilized at a rate of 220 kg N ha-1 yr-1 in metered applications of urea. Runoff was collected and analyzed for volume, suspended and soluble solids, NH4-N, NO3-N, total N, PO4-P, total soluble P, and total P. Runoff losses of sediment and all nutrients were extremely low. Runoff losses of total N were significantly (P ≤ 0.05) higher when comparing the liquid and granular treatments to the control, although there was no difference between fertilizer treatments. Losses for all forms of P and sediment did not significantly differ with regard to treatment. Soil percolate (0.75 m depth) was collected monthly from the various treatments. Percolate NO3-N concentrations from the liquid and granular treatments did not differ significantly, although both were significantly higher than the untreated control. Soil cores (2.1 m depth) were collected every spring and fall in 0.30-m increments. Nitrate-N concentrations generally decreased with depth; however, the granular treatment exhibited a higher soil NO3-N concentration than either the liquid or control treatments. These results indicate that when compared with agronomic row crops, nutrient and sediment losses from turf via runoff, and leaching are very low.