Figure - available from: Crop Science
This content is subject to copyright. Terms and conditions apply.
Environmental data from sensors that were under ice in both testing years. O2 is shown as percentage, CO2 in parts per million, and soil temperature in degrees Celsius. The O2 sensors placed at 2.54 cm in the first winter of the study malfunctioned, and data are not reported. CO2 sensors reached maximum reading of 40,000 ppm in 2023. Vertical red solid lines are the ice‐out dates, and vertical black dashed lines are 40 days after melting in each experimental year.
Source publication
Ice encasement is a major concern for turfgrass managers in cold climates; however, there is a lack of data about both which turfgrasses are best suited for survival under these conditions and the reasons behind the superior recovery of some grasses from long‐term ice encasement. In this study, we encased golf course putting greens‐height field plo...
Citations
Ice encasement (IE) is one of the big challenges in winter stress management on golf course putting greens in Northern Scandinavia. The turfgrass is damaged due to lack of oxygen (hypoxia or anoxia) and accumulation of toxic by‐products of anaerobic respiration. Breeding IE‐tolerant turfgrass species and varieties is the best defense against these challenges. A method to simulate ice encasement was tested to screen selected varieties of winter‐hardy bentgrass species and red fescue subspecies. Note that 32 varieties were chosen from the SCANGREEN trial seeded at NIBIO Landvik, Norway, in 2019. Samples were taken in December 2020, 2021, and 2022, vacuum sealed in plastic, and stored in darkness at 0.5°C for up to 77 days to test them for their tolerance to simulated ice encasement (SIE). Samples were incubated at different intervals; plants were potted, and tiller survival was tested after 4 weeks of regrowth. Lethal duration of ice encasement (LD 50 ) that is, the number of days under anoxia that kills 50% of the plant population for each species and variety was calculated. The results showed that the ranking of cool season turfgrass species for tolerance to SIE was velvet bentgrass > Chewings fescue > slender creeping red fescue = colonial bentgrass > creeping bentgrass. This ranking does not fully reflect the ranking found in field tests where velvet bentgrass was superior together with creeping bentgrass. SIE caused a more rapid development of anoxia than IE in the field, and we hypothesize that creeping bentgrass is less tolerant to these conditions compared to the other species tested. To make the SIE method more representative for IE in field, it should be further adapted with incubation at lower temperatures, and with acclimation conditions to be standardized prior to sampling. Within species, the best tolerance to IE was found in velvet bentgrass Nordlys, creeping bentgrass Penncross, Chewings fescue Lykke, and slender creeping red fescue Cezanne.
Red fescue (RF, Festuca rubra L.) is one of the most widely used turfgrass species in Europe. The subspecies Chewings fescue (CF) and slender creeping red fescue (SlCRF) are used on putting greens because they tolerate a mowing height of 4–5 mm. Previous research has shown CF to be more winter‐hardy than SlCRF, however, SlCRF has a greener winter color. Our objective was to find the optimal weight ratio of the two subspecies in seed blends for greens in contrasting climatic regions of the Nordic countries. Musica and Cezanne (reference varieties in SCANGREEN variety testing since 2012) were selected as representatives for CF and SlCRF, respectively. Seed blends including CF/SlCRF in weight ratios of 75/25, 50/50, and 25/75 were compared to pure CF and SlCRF at Sydsjælland GC, Denmark, NIBIO Landvik, Norway, NIBIO Apelsvoll, Norway, and Reykjavik GC, Iceland as an add‐on to SCANGREEN variety testing 2015–2018. Results showed the optimal blends to produce higher turfgrass quality and tiller density than monocultures of either subspecies at all sites except Apelsvoll where plots were killed during the first winter. The best‐performing CF/SlCRF blend was 50/50 at Sydsjælland and Landvik and 75/25 at Reykjavik. While this shows seed blends to have advantages compared with the pure subspecies, the study should be repeated with a focus on dollar spot ( Clarireedia spp.), which has become a major turfgrass disease in Southern Scandinavia since these trials were conducted.
