No abstract

Core Ideas WinRHIZO technology may provide a method to analyze stolon morphology of grasses. The scanned length closely predicted the manually measured one. WinRHIZO technology overestimated diameter when the whole stolon was scanned. WinRHIZO, a root‐measuring system, may provide an alternative, reliable, and fast method to analyze stolon morphology of grass species. This study evaluated the possibility to use WinRHIZO technology to measure total length and average diameter of bermudagrass [Cynodon dactylon (L.) Pers.] stolons. The length and diameter of 70 stolons collected from four turf‐type cultivars and a wild bermudagrass were measured with a ruler (length) and caliper (diameter), and using WinRHIZO technology, a scanner‐based image analysis system. The scanned length closely predicted the manually measured one and can be successfully used to determine stolon length in samples with a significant amount of biomass. WinRHIZO technology overestimated diameter values when the whole stolon was scanned, while the diameter prediction was more precise when nodes were removed and only internodes were measured.

Plant biodiversity is an important feature of grassland ecosystems, as it is related to the provision of many ecosystem services crucial for the human economy and well-being. Given the importance of grasslands, research has been carried out in recent years on the potential to monitor them with novel remote sensing techniques. In this study, the optical diversity (also called spectral diversity) approach was adopted to check the potential of using high-resolution hyperspectral images to estimate α-diversity in grassland ecosystems. In 2018 and 2019, grassland species composition was surveyed and canopy hyperspectral data were acquired at two grassland sites: Monte Bondone (IT-MBo; species-rich semi-natural grasslands) and an experimental farm of the University of Padova, Legnaro, Padua, Italy (IT-PD; artificially established grassland plots with a species-poor mixture). The relationship between biodiversity (species richness, Shannon’s, species evenness, and Simpson’s indices) and optical diversity metrics (coefficient of variation-CV and standard deviation-SD) was not consistent across the investigated grassland plant communities. Species richness could be estimated by optical diversity metrics with an R = 0.87 at the IT-PD species-poor site. In the more complex and species-rich grasslands at IT-MBo, the estimation of biodiversity indices was more difficult and the optical diversity metrics failed to estimate biodiversity as accurately as in IT-PD probably due to the higher number of species and the strong canopy spatial heterogeneity. Therefore, the results of the study confirmed the ability of spectral proxies to detect grassland α-diversity in man-made grassland ecosystems but highlighted the limitations of the spectral diversity approach to estimate biodiversity when natural grasslands are observed. Nevertheless, at IT-MBo, the optical diversity metric SD calculated from post-processed hyperspectral images and transformed spectra showed, in the red part of the spectrum, a significant correlation (up to R = 0.56, p = 0.004) with biodiversity indices. Spatial resampling highlighted that for the IT-PD sward the optimal optical pixel size was 1 cm, while for the IT-MBo natural grassland it was 1 mm. The random pixel extraction did not improve the performance of the optical diversity metrics at both study sites. Further research is needed to fully understand the links between α-diversity and spectral and biochemical heterogeneity in complex heterogeneous ecosystems, and to assess whether the optical diversity approach can be adopted at the spatial scale to detect β-diversity. Such insights will provide more robust information on the mechanisms linking grassland diversity and optical heterogeneity.

Warm-season grasses are known to be more wear tolerant than cool-season grasses, but in northern Italy the latter are generally preferred for ornamental turfgrasses and athletics fields. The Po River valley, in the North of Italy, is a typical transition zone where species and cultivar selection play a very important role in establishing successful turfgrasses with high stress tolerance, including foot traffic. The aim of this research was to evaluate the traffic tolerance and adaptation of 25 cultivars of three coolseason turfgrass species to transitional growing conditions of Italy. A study was conducted over a two-year period at the experimental farm of Padova University in Legnaro. The species studied were tall fescue (Lolium arundinaceum), kentucky bluegrass (Poa pratensis), and perennial ryegrass (Lolium perenne). Simulated traffic was applied using a Brinkman traffic simulator at a level equivalent to one soccer game per week. Turfgrass quality and density were assessed every week using a 1 to 9 visual scale during traffic treatments each year. Furthermore, turfgrass canopy height was measured weekly for calculating daily vertical growth rate (mm d-1) in spring, summer, and autumn. Trafficked plots exhibited lower quality than nontrafficked, primarily as a result of decline in turf density. The effect of traffic on density was more evident in the second year wherein all species exhibited ratings lower than 5.0. Traffic did not affect turf growth for perennial ryegrass and tall fescue, while a drastic decrease in growth rate in the second year of study was observed for kentucky bluegrass. Perennial ryegrass had lower density than tall fescue and kentucky bluegrass, especially in summer and autumn of the first year when it showed ratings lower than 6.0. Different responses occurred among kentucky bluegrass cultivars, while perennial ryegrass and tall fescue cultivars responded similarly. Results indicated a high quality and environmental adaptability of 'Rhambler SRP' tall fescue. Among kentucky bluegrass cultivars, 'Mystere' displayed the best wear tolerance with a decrease of density from 5.5 to 4.3 only during the second year. Perennial ryegrass cultivars were similarly affected by traffic, except for 'Yorktown III' which showed the lower performance in both traffic and non-traffic conditions reaching a turf density rating lower than 5.0 in both years of study.

Bans on the use of synthetic herbicides require innovative management approaches to maintain the attractiveness and usability of turfgrass swards. Such measures should include the use of locally adapted cultivars that germinate and establish quickly, resulting in the densest possible stands. Additionally, a number of turfgrasses have been reported to produce allelopathic substances that inhibit common turfgrass weeds. Mowing heights should be set to achieve maximum weed suppression while still providing acceptable quality for desired use. Sustainable turfgrass management programs have led to a reduction in fertilizer inputs; however, without the availability of herbicides, fertilization regimes need to be re‐examined. The literature suggests that broadleaf weeds are reduced but never fully controlled when more N is applied; therefore, finding a balance between what is needed and what is environmentally safe and sustainable is critical. Organic herbicides include plant pathogens from the fungus Phoma and strains of the bacterium Pseudomonas fluorescens. Both can be used to control several weeds common to turfgrasses. Acetic acid has also been shown to have herbicidal activity; however, it has limited residual activity, and its efficacy remains questionable on mature weeds. Thermal weed control can be used to sterilize a seedbank or spot treat existing weeds. Future turfgrass breeding programs could focus on understanding and enhancing the allelopathic potential of turfgrasses to outcompete weeds more effectively. Furthermore, more research should be directed at assessing the competitiveness of certain turfgrasses against weeds within the limitations of producing turfgrass areas of acceptable aesthetics and playing quality.