Shade Tolerance of ProVista Kentucky Bluegrass versus Conventional Blends

Abstract

Shade stress is a common problem encountered in turfgrass management situations worldwide. As a species, Kentucky bluegrass (Poa pratensis L.) possesses relatively poor shade tolerance, which limits its use in low light situations. The objective of this study was to determine the comparative shade performance and minimal daily light integral requirements (DLIm) of Kentucky bluegrass. Field studies were conducted under shade treatments producing seasonal average DLI ranging from 1.9 to 55.9 mol m^2 d^-1 during year one and from 1.98 to 40.65 mol m^2 d^-1 during year two. Based on non-linear regression of DLI vs. turfgrass quality during the final rating date of both years, DLIm required for acceptable turf quality ranged from 7.5 mol m^-2d^-1 for ProVista and from 22.5 2 mol m^-2d^-1 for Conventional Kentucky bluegrass. Improved turf quality of ProVista under low light intensities appeared to be related to reduced rates of leaf elongation, improved stand density, and elevated leaf chlorophyll contents.