Nitrogen and Phosphorus Leaching from Fertilizer Applied on Golf Course: Lysimeter Study

Abstract

Fertilizers applied to turfgrass may pose a threat to surface and groundwater quality, and hence, a study was carried out to evaluate the fate of fertilizer applied to turfgrass of the Clearwater Bay Golf and Country Club in Hong Kong. Lysimeters with reconstituted soils collected from fairways and greens with Bermudagrass (Cynodon dactylon) growing in the surface were used to evaluate the leaching loss of nitrate (NO3-), ammonium (NH4+), and phosphate (PO43-) for 22 weeks under greenhouse condition. Both soils received a slow release fertilizer at an application rate of 25 (low) or 50 (high) kg N ha-1, and an application frequency of monthly and fortnightly for fairways and greens, respectively, simulating the fertilizer application strategy of the golf course. Both low and high fertilizer application rate supported the same amount of biomass production for each soil type. Breakthrough of NO3- occurred only in greens after 11 weeks of leaching, but the total amount of NO3- leached did not differ significantly for the two different fertilizer application rates. The continued addition of fertilizer to greens resulted in a final leachate NO3- concentration exceeding 45 mg L-1, while fairways maintained a concentration below 5 mg L-1. Also PO43- concentration in leachate of greens exceeded the surface water standard of 0.3 mg L-1. The results of the lysimeter study showed that the current application rate on greens would create adverse environmental impacts on the surface water and groundwater due to leaching loss of PO43- and NO3-.