Is Turfgrass an Environmental Ally or An Unsustainable Option in Our Urban Environment? Article by: Michael Brownbridge Grasses play a vital role in natural areas and in agriculture, and of course in urban environments and recreational spaces around the world. Grassed areas contain hundreds of individual plants, each of which provides ecosystem services and benefits. Grass makes an enormous contribution to the aesthetics and performance of our living landscape, and we need to inform the conversation around the numerous benefits that accrue from having optimally maintained and functional green space. Like other plants in the landscape, grasses are affected by many environmental factors and are often grown in less-than-ideal soils, such as those found in residential and roadside settings. Yet today, we have access to a wide variety of turfgrasses, which are better adapted to sub-optimal soils. When making selections, consider the location and desired function, and how the grass will perform in the climate of the future. For example, turfgrass varieties with superior ‘environmental performance’ are now available. The Turfgrass Water Conservation Alliance carries out studies to evaluate turfgrasses and their capacity to withstand drought conditions. Grasses are given the TWCA seal of approval only if they ‘…provide clear water conservation benefits, and can survive under reduced or limited water while still maintaining overall plant health’ (TWCA; http://www.tgwca.org/). What about grasses with other desirable traits? The capacity to survive in harsh environments, e.g. high salinity or compacted soils. Selection of turfgrasses that have the requisite traits for roadside plantings will enhance their functionality and sustainability in this challenging environment, and more attention should focus on the evaluation of species and cultivars for this purpose.
It doesn’t get much more challenging than this—yet grasses survive. (Image courtesy of Vineland)
In an integrated greenspace, healthy turfgrass will: • • • • • • • • •
Filter and capture runoff, prevent soil erosion Allow water infiltration in the soil Reduce heat Improve air quality Absorb noise Absorb CO2 Help mitigate effects of climate change Support biodiversity (both plant and animal life) Provide a great place to relax and play
Some of the benefits derived from turf.
For residential use, various ‘creeping’ tall fescues and ryegrasses have excellent aesthetic qualities. They are competitive grasses, have lower maintenance requirements and importantly, are also very hardy under drought conditions. However, their winter tolerance is sometimes lacking, so more research is needed to identify the best cultivars adapted to our northern climate. High endophyte grasses also have many desirable attributes. At Vineland, we established test plots containing creeping tall fescue, creeping ryegrass, high endophyte tall fescue and high endophyte ryegrass in 2015. Two and a half years later (including one drought year) these grasses still cover >80% of the plot area, and this was achieved with no maintenance other than mowing.
the soil; losses may be reduced or prevented by optimizing Nitrogen rate, using slow-release formulations, and better timing of application. 4. Losses were reduced when the fertilizer application was split (versus a one-time application). The results clearly indicate that a correctly fertilized lawn will retain more water and nutrients than a poorly maintained area, leading to improved performance and functionality. Well-maintained and healthy turf is a valuable component of a living landscape, contributing to a better environment, better living space, and a happier and healthier lifestyle.
High endophyte fescue (HEF) and Kentucky blue grass (KB) plots, 18 mo after seeding. (Image courtesy of Vineland)
Testing the same grasses on sod farms in Ontario, the high endophyte and ‘creeping’ grasses covered >98% of the plot area after 18 mo, preventing any weed ingress. Contrast this to the Kentucky blue blend, which covered <60% of the plots, with at least 5% of the plot area covered by broadleaf weeds.
Acknowledgements This research was supported in part by Growing Forward 2; the Quebec-Ontario Cooperation for Agri-food Research Competition Project SR 9302 ‘Integrated strategies for production and management of turfgrass sod with improved environmental performance’; and the Ontario Turfgrass Research Foundation. Special thanks to Taro Saito, Bernhardt Steinwender and Paul Côté (Vineland).
It is clear that low maintenance, durable grasses are now available that are well adapted to life in an urban setting. This starts to change the conversation around use of grasses in our green infrastructure.
Michael Brownbridge is the Research Director for Horticultural Production Systems at Vineland Research and Innovation Centre. Guillaume Grégoire, Professionnel de recherché, Centre de Recherche en Horticulture, Université Laval.
How to keep turfgrass in top condition so it can provide the greatest benefits? Researcher Guillaume Grégoire at Laval University has been conducting a long-term study to assess the impact of fertilization practices on turfgrass performance, and to provide empirical evidence on nutrient losses through runoff and leaching. Some important ‘take-homes’ from the study so far: 1. Runoff was greater from unfertilized vs fertilized plots; the thicker grass canopy in fertilized plots, intercepted the water, and it is likely that denser root growth allowed it to permeate into the soil. 2. Potassium losses were higher in runoff from unfertilized (including compost-treated) versus fertilized plots. 3. There were slightly higher levels of Nitrogen in runoff and leachate from fertilized plots; this was expected given that plots were fertilized and due to the ‘mobility’ of Nitrogen in
Join Michael at the Green Industry Show & Conference and learn more about this topic in his session “Changing Perceptions and Promoting Sustainable Turfgrass Systems,” or catch his seminar with fellow Vineland employee Dr. Darby McGrath: “Urban Ecosystems: Moving from Concept to Construction.”
Compare this to Kentucky bluegrass, which, over the same period, has dwindled to less than 30% coverage.