The effect of traffic on turfgrass root morphological features

Abstract

Foot traffic is recognised as the most frequent and damaging stress to sports turf. Wear and compaction caused by play can be a greater factor contributing to differences among turfgrass species to traffic stresses. A better understanding of factors affecting wear tolerance is likely to be a useful tool for grass breeders in terms of cultivar recommendations for sports fields. The objective of this study was to determine whether the wear tolerance of turfgrass cultivars was dependent on root morphology. The experiment was conducted in 2012 and 2013 in Paczoltowice in the south of Poland. This field trial was set out in a split-plot design arranged in randomised complete blocks with three replications with cultivars as a main plot and traffic treatment as a subplot compared with an untreated control. Thirty seven cultivars, representing seven turfgrass species were established on loamy sand. Traffic treatments were applied as a strip using Brinkman traffic simulator (BTS). Roots in the experimental plots were sampled from the 0 to 15cm soil layer in June 2012 and June 2013. Root morphological parameters were determined namely root length density (RLD), mean root diameter (MRD), root surface area (RSA) and root dry matter (RDM). Wear resistance of turfgrass cultivars was estimated using the Turf Cover Index (TCI) based on the percentage of turf cover on control and treated plots.The results showed significant differences among the tested cultivars, in terms of all root morphological characteristics. The highest root biomass and length was produced by cultivars in the upper 0–5cm soil layer. The most frequent fraction of the RLD for all tested cultivars was that with a diameter of 0.05–0.1mm, representing approximately 63% of all root length. It was observed that the tested cultivars significantly differed in their TCI after the BTS compaction. The poorest wear tolerance, was recorded for most of Festuca ovinacultivars, namely ‘Bardur’, ‘Barok’, and ‘Noni’ and some of Festuca rubra, ‘Audubon’, ‘Dark’ and ‘Nimba’. All cultivars of Lolium perenne were assessed as having a very good wear tolerance. The roots of investigated turfgrass cultivars showed a different reaction to trafficking. Most of the investigated cultivars reacted negatively to the traffic simulation by Brinkman roller. The BTS treatment reduced root length, dry matter and surface. However, some cultivars, mainly those of L. perenne,showed positive reactions to trafficking. It was found that the wear tolerance was positively correlated with the RLD in the root diameter range from 0.1 to 2.0mm. The higher RDM, RSA and MRD increased wear resistance of turfgrass cultivars.