Rooting characteristics and turfgrass quality of three bermudagrass cultivars and a zoysiagrass

Abstract

Warm season turfgrasses are increasingly used throughout the transitional areas of Mediterranean countries due to their low water requirements. A two-year field study was carried out in north-eastern Italy to evaluate the turf canopy quality and root system architecture of three seeded bermudagrass cultivars (La Paloma, Princess-77 and Yukon), and a zoysiagrass (Companion) under non-irrigated conditions. Plots (1.6×4.5 m) were established in July 2005 and arranged in a randomized complete block with three replicates. Visual quality ratings were assessed weekly from April to November in 2006 and 2007. Soil cores were collected at depths of 0–3, 3–8, 8–15, 15–25 and 25–40 cm in August 2006, January 2007, May 2007 and September 2007 to measure main rooting characteristics: root length density (RLD), root mass density (RMD) and root diameter. Companion zoysiagrass had higher canopy quality than bermudagrass cultivars in early spring and in the late growing season, while it displayed poorest quality from June to October. Among the bermudagrass cultivars, Yukon showed the highest quality in both years. Differences in RLD among grasses appeared to be related to seasonal changes in air temperature and precipitation. In August 2006 Companion zoysiagrass averaged 3.5–4.4 cm cm−3 less RLD than bermudagrass cultivars La Paloma and Princess-77. Visual turf quality was positively correlated to the RLD and RMD in the 25–40 cm soil layer, whereas no correlations were found with root diameters nor any parameter collected in the upper soil layers. Deep-rooting cultivars may have an advantage in deficit soil moisture periods resulting in higher quality turf throughout the year.