Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2025
Abstract
Abstract Turfgrass winter kill due to freeze/thaw cycles and ice encasement (IE) is a problem on putting greens the Nordic countries. Our objectives were (1) to investigate how green coverage with impermeable plastic before IE affects soil temperature, O 2 and CO 2 concentrations, winter survival and spring recovery of creeping bentgrass (CRB), red fescue (RF), and annual bluegrass (AB) and (2) to explore how these turfgrasses are affected by snow and ice removal during the entire winter or parts of it. Six treatments were imposed on 5‐month‐old turf of the three species during the winters 2020/2021 and 2021/2022 at NIBIO Apelsvoll, Norway (60°42′ N). With an average soil temperature at 2‐cm depth of −0.9°C and the lowest O 2 concentrations around 5%, conditions under IE or plastic + IE treatments never became anoxic. On average for six treatments and 2 years, CRB and RF had significantly better winter survival (both 52%) than AB (25%). Turfgrass winter survival, spring color, and spring growth were significantly better (62% survival on average for species) with plastic between the grass and 10‐cm IE than with 10‐cm IE directly on the grass (23% survival). Snow and ice removal throughout the winter or before IE in early January improved turfgrass freezing tolerance in January but did not improve winter survival, green color, or spring growth compared with the control treatment with natural winter conditions. We conclude that putting greens in areas with unstable winters and risk for prolonged IE ought to be protected by impermeable plastic. Ventilation under the plastic may be necessary on old greens with more organic matter than in this experiment. On frozen uncovered greens, it is better to avoid prolonged IE by snow removal before rain or warm spell in December/early January than by mechanical ice removal in March.
Abstract
Plants in raingardens are important for evapotranspiration and maintaining infiltration properties. Hydrological conditions, however, fluctuate between dry and saturated, strongly affecting plant performance and limiting plant selection in design. This study experimentally assessed whether fluctuating hydrology impacts growth, flowering, and root morphology in the drought-tolerant Knautia arvensis and the wet-tolerant Lythrum salicaria. The hydrological regimes included repeated cycles of dry and wet conditions: Drought regime with cycles of a drought period followed by a single watering; Flooding regime with cycles of 72-hour flooding and a 48-hour drained period; and a subsequent Drought+Flooding regime with cycles of 72-hour flooding followed by a drought period. Knautia reduced growth under flooding cycles, while Lythrum reduced growth and flowering under drought cycles. Repeated consecutive drought and flooding cycles negatively influenced the growth of both species in the same way, with flooding affecting Knautia and drought affecting Lythrum. Lythrum showed more plasticity than Knautia, allocating more biomass to roots during drought cycles. Flooding cycles reduced root length in Knautia, while the drought cycles and consecutive Drought+Flooding cycles increased root diameter and decreased root length in Lythrum. Both species had coarse roots (> 2 mm) to support infiltration through biopores. If we assume that raingardens have free drainage and only rarely flood, drought-tolerant traits are more important. However, wet-tolerant species can benefit the system, especially through higher water use. This research contributes to the ecological understanding of plant responses to fluctuating hydrology, enabling a better plant selection for effective raingardens.
Authors
Karin Juul HesselsøeAbstract
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Authors
Michelle DaCosta Jefferson Lu J. Scott Ebdon Eric Watkins Dominic Petrella Michael Andrew Bekken Trond Olav Pettersen Trygve S. AamlidAbstract
Winter damage of golf turf in northern environments is a persistent challenge, and reseeding is often necessary to promote recovery and to maintain adequate density and uniformity for play. However, adverse conditions associated with spring seedings can negatively impact reestablishment of creeping bentgrass ( Agrostis stolonifera L.) (CBG) on golf greens, tees, and fairways. The objectives of the research were to examine different strategies to promote rapid reestablishment of CBG in early spring, including cultivar selection, use of a synthetic cover, and application of plant health products. To assess the impacts of CBG cultivars and cover on reestablishment, 12 cultivars and two cover treatments (without or with a permeable synthetic cover) were established at two locations in 2021 (South Deerfield, A, and Saint Paul, MN). The effects of plant health products on CBG establishment were assessed in separate field trials at two locations in 2021 and 2022 (South Deerfield, MA, and Grimstad, Norway). Plant health product treatments were applied on a weekly basis following emergence and included: control (water), chitosan, silica, acibenzolar S‐methyl, glycine betaine, seaweed extracts (alone or together with humic substances), trinexapac‐ethyl, and gibberellic acid. Soil and air temperatures were monitored, and plots were visually assessed for changes in percent green turfgrass cover. The use of a permeable cover increased soil temperatures and decreased the time to achieve 50% turfgrass cover by 7–12 days, depending on location and regardless of cultivar. Compared to effect of covering treatment, most CBG did not significantly vary in spring establishment rates, except for Independence, which exhibited slower establishment. Among the various plant health products tested over 2 years and two locations, we did not identify any specific product that consistently enhanced early spring establishment of CBG.
Abstract
Abstract 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.