Abstract:A field study on the effectiveness of two slow-release fertilizers ( Isobutylidene diurea-IBDU and Polymer-coated fertilizer) on the quality and growth of perennial ryegrass was conducted in Northern China. The results indicated that the slow-release fertilizers applied in spring could sustain much longer acceptable and uniform turfgrass quality and biomass of growth compared with urea applied. However, applying slowrelease fertilizers to the perennial ryegrass turf in fall could not produce the imp roving effects on the turf quality. Polymer-coated fertilizer applied in fall showed some what lower trufgrass quality than the ones with urea applied.