EFFECTS OF SHADING ON LOLIUM PERENNE AND POA PRATENSIS TURF

This paper examines the tolerance Lolium perenne and Poa pratensis to shade. L. perenne and P. pratensis are considered among the most popular turfgrass species for ornamental and sport purposes. A two-level reduction in Photosynthetically Active Radiation (PAR) (30% and 70%) was simulated using mobile artificial covers. The shading effects were studied by measuring variations in growth rate and by determining morphological variations of the leaves. L. perenne and P. pratensis were only slightly affected by the 30% reduction of solar radiation, both for long and short time application. In contrast increased shading (70%), even for a short time, resulted in a lower biomass production and in leaf characteristics modifications. In the permanently shaded plots, turf quality (density and aesthetic appearance) was severely reduced for both species. Consequently, in situations of artificial or natural reduction in solar radiation, turf re-establishment is expected to occur more frequently.