Effects of nitrogen application timing on growth and quality of a turfgrass mixture

Abstract

A 3-year field study was conducted to determine the influence of nitrogen (N) application timing on the growth and quality of a turfgrass mixture consisting of perennial ryegrass (Lolium perenne L.), Kentucky bluegrass (Poa pratensis L.), creeping red fescue (Festuca rubra var, rubra L.), and chewings fescue (Festuca rubra var. commutata Gaud.) under irrigated conditions. Nitrogen was applied annually at the rate of 30 g m(-2) year(-1), with six application regimes: control (no N), single spring (30 g m(-2)), single fall (30 g m(-2)), spring + fall (15 + 15 g m(-2)), spring + summer + fall (10 + 10 + 10 g m(-2)), and monthly from April through September (5 g m(-2)).

Color, turf quality, clipping weights, and shoot density were correlated with fertilizer rates and application timing in this study. Fertilization monthly or every 2 months resulted in more uniform color and turf quality and less clipping weights than with comparable heavy spring and fall fertilizations. Heavy N applications in the fall did not cause winter injury and produced significantly darker color and more uniform appearance in early spring than other N applications. All N-fertilization regimes increased shoot density, but spring fertilization stimulated density the most. Nitrogen applied monthly or every 2 months was enough to enhance the color, turf quality, and shoot density of the turf during the growing season but did not greatly affect the growth rate.