The scarcity of potable water for irrigation has become an issue even in the Nordic countries. In the three work packages (WPs) of this project we study ways to reduce irrigation while retaining turfgrass quality on fairways mowed at 18-20 mm.
In WP1, we evaluated 42 varieties of 10 species for drought tolerance and recovery on sandy soil under a rain shelter at NIBIO Landvik. Three 8-wk drought periods were implemented in 2024 and 2025, each period followed by 3 wks recovery under irrigation. Turfgrass quality, soil water content (SWC) and turfgrass coverage were determined twice a week, the latter from digital images analyzed using https:// turfanalyzer.com. On average, for the varieties and three experimental runs, results showed that the ability to retain green coverage during prolonged drought deceased in the order: Tall fescue>>sheep fescue>perennial ryegrass>hard fescue>Kentucky bluegrass>strong and slender creeping red fescue >colonial bentgrass>Chewings fescue>creeping bentgrass. Among the species with less than average drought tolerance, creeping bentgrass, colonial bentgrass, strong creeping red fescue and Kentucky bluegrass had the fasted recovery once irrigation was resumed.
In WP2, the field trials testing seven soil surfactants for their ability to retain turfgrass quality and coverage under drought conditions were finished in 2024. In spring 2025, the following surfactants were selected for further testing in WP3 and in the parallel project FAIR WATER II: H2PRO Trismart (the best compromise between green coverage and water usage), Magnum 357 Calibre and Qualibra (the highest turfgrass quality during the entire 8 week drought period or during the last 2 weeks, respectively), and ProWet Evolve (the greatest increase in SWC).
In WP3, the first-year comparison of three seed mixtures seeded in Aug.-Sept. 2024 at Landvik, Norway and Osnabrück, Germany did not show the same convincing results for a mixture of 65% tall fescue, 15% perennial ryegrass and 20% Kentucky bluegrass as expected from WP1. In Germany, there were no differences among seed mixtures, while in Norway, the highest green coverage and turfgrass quality under drought was found with a mixture of five fine fescue species/subspecies with the highest proportion of slender creeping red fescue. We believe that the poor performance of the mixture of tall-fescue (65%, w/w), Kentucky bluegrass (20%) and perennial ryegrass (15%) was caused by the time period being too short for tall fescue to develop a mature stand with deep roots before the drought period started in May 2025. Tall fescue was overseeded in September 2025 to increase the proportion of tall fescue in the turfgrass canopy in these plots in 2026. Among surfactants, H2Pro Trismart performed slightly better than Magnum 357 Calibre at both sites. The trials continue in 2026.
