Over the last decade, the scarcity of potable water for irrigation has become a greater issue in northern Europe. In the three work packages (WPs) of this project, we study methods to reduce irrigation while retaining turfgrass quality on golf course fairways.
In WP1, we evaluate 42 varieties of 10 turfgrass species for drought tolerance and recovery in sandy soil under a rain shelter at NIBIO Landvik, Norway. The first drought period was implemented from 30th April to 25th June 2024, followed by a 3-week recovery period. Turfgrass coverage was determined through digital images of each plot twice a week and analyzed using https://turfanalyzer.com. The main findings from 2024 were: (1) tall fescue was least affected by drought, followed by perennial ryegrass and sheep fescue; (2) tetraploid varieties of perennial ryegrass were more drought tolerant than diploid varieties; (3) slender creeping red fescue was more drought tolerant than Chewings fescue and strong creeping red fescue. The trial will be repeated in 2025.
In WP2, we continued testing seven soil surfactants for their ability to retain turfgrass quality and coverage on a fairway seeded in sandy soil under a rain shelter. The surfactants were applied in early spring before imposing drought from 15th May to 10th July. Individual plots were irrigated with 8 mm of water only when turfgrass coverage fell below 70%, as determined from digital images. Control treatments included a negative control (no surfactant but the same criterion for irrigation) and a positive control irrigated to field capacity three times a week. Unlike in 2023, significant differences were detected in the last three weeks of the drought period. Plots treated with H2PRO had better coverage and less consumption of irrigation water; plots treated with Qualibra had the higher turfgrass quality; and plots treated with ProWet Evolve had higher soil moisture contents than the negative control treatment.
In WP3, two supposedly drought resistant seed mixtures were composed based on WP1, and new trials were seeded in a split-plot design in sandy soils at NIBIO Landvik, Norway and Osnabrück University, Germany in August 2024. One mixture was primarily based on slender creeping red fescue, sheep fescue and hard fescue, the other on tall fescue and tetraploid perennial ryegrass. A standard ‘Nordic’ seed mixture of Kentucky bluegrass and Chewings fescue was included as a control. In 2025, the most promising surfactants from WP2 will be tested on subplots in these trials to find the optimal combination of seed mixture and surfactant for better drought resistance.
