Determination of crop coefficients (Kc), the ratio between actual (ETa) and reference evapotranspiration (ET0), is necessary to schedule irrigation. Our objective was to determine Kc, turf quality and growth rate under daily irrigation to field capacity (FC = −3 kPa tension) and drying. Minilysimeters installed in a green (mowing height 3–5 mm) and fairway (15 mm) were weighed during four periods of 4–10 days duration in 2009 and 2010. Crop coefficients on the second and subsequent days after irrigation were not significantly different among species and averaged 0.81 and 0.91 on green and fairway, respectively. On the first day after irrigation, the Kc varied from 1.67 to 2.85 and decreased in the order Agrostis capillaris > Festuca rubra ssp. litoralis > F. rubra ssp. commutata > A. stolonifera > A. canina on the green, and F. rubra ssp. litoralis > Lolium perenne > F.rubra ssp. rubra > Poa pratensis > F. rubra ssp. commutata on the fairway. Drying reduced the average daily height growth from 0.98 to 0.74 mm on the green and 1.97–1.72 mm on the fairway. Scores for turf quality were reduced but remained acceptable. Although the Kc during the first day after irrigation to FC may be overestimated due to latent soil heat and a possible oasis effect, we conclude that irrigation to FC should be avoided as it causes excessive water use.

Red fescue (RF, Festuca rubra L.) is used on golf putting greens in the Nordic region due to its high disease resistance and low requirements for nitrogen (N) and water, but low density and growth rate makes RF susceptible to annual bluegrass (AB, Poa annua L.) invasion. Putting greens seeded with RF + bentgrass (Agrostis sp.) may be more competitive with AB but also have different playing characteristics. Our objective was to compare RF, RF + colonial bentgrass (CB, Agrostis capillaris L.), and RF + velvet bentgrass (VB, Agrostis canina L.) putting greens at two mowing heights (4.0 or 5.5 mm), three N rates (5, 10, or 15 g N m−2 yr−1), and three phosphorus (P)–arbuscular mycorrhizal fungi treatments (0 and 1.8 g P m−2yr−1 without inoculation and 0 g P m−2yr−1 with inoculation). The four‐factorial experiment was conducted in 2011 and 2012 at Landvik, Norway. Red fescue provided lower visual quality and density and less competition against AB than RF + bentgrass combinations. Increasing the N rate from 5 to 15 g N m−2yr−1 increased the proportion of bentgrass tillers from 53 to 64% in RF + CB and from 86 to 92% in RF + VB. Surface hardness increased in the order RF + VB < RF + CB < RF turfs. Ball‐roll distance decreased with increasing N rate and was longer with RF and RF + VB than with RF + CB. The main effects of N and mowing height on AB invasion were not significant, but lower mowing increased AB competition in RF. Mycorrhiza colonization of roots was not significantly affected by any practice, and neither P nor arbuscular mycorrhizal fungi influenced the competition against AB.

wounded and nonwounded leaves were inoculated. Fresh wounds were made with a sterile needle on 10 detached leaves and 10 leaves on five living plants for fungi MLL1 to MLL5 independently. Mycelial plugs of each fungus were applied to wounded and nonwounded leaves. For the control, 10 leaves on five living plants were inoculated with agar plugs in a similar manner, to both wounded and nonwounded leaves. All treatments were incubated in a humid chamber in the dark at 28°C. Leaf spots identi cal to those observed in the field were observed on the wounded leaves inoculated with fungus MLL3 after 3 to 4 days, while the other four fungi and the control remained symptomless. The 10 nonwounded leaves inocu lated with fungus MLL3 were also infected after 5 days. The fungus, with the same colony and conidial morphology as MLL3, was re-isolated from the affected leaves. The pathogenic test was repeated three times under the same conditions. Hyphal tips of MLL3 were transferred to PDA for mor phological observation. Colonies of white-to-dark-gray mycelia, black on the underside, formed on PDA. The colonies were further identified as Altemaria sp., based on the dark brown, obclavate to obpyriform catenulate conidia with longitudinal and transverse septa tapering to a prominent beak attached in chains on a simple and short conidiophore (3). Conidia varied from 22.5 x 40.26 to 3.95 x 5.79 pm and had three to eight trans verse and zero to four longitudinal septa, with a beak length of 0 to 7.25 pm. For molecular identification, PCR was carried out using internal tran scribed spacer (ITS) region primers ITS1/ITS4, partial sequences of the beta tubulin gene primers B tla-B tlb (1), and A. alternata species-specific primers AAF2/AAR3 (2). The PCR products were subjected to direct sequencing. The resulting sequences were compared against the GenBank nucleotide database by using a BLAST alignment, which revealed that MLL3 had 99 to 100% identity with A. alternata for the ITS, B tla-Btlb, and AAF2/AAR3 regions (GenBank Accession Nos. KF669893, GQ240308, and KJ716876, respectively). Sequences for MLL3 were deposited in GenBank under accession numbers KJ767515, KJ921779, and KJ921778. According to both morphological and sequence analyses, the pathogen of the leaf spot of B. gymnorrhiza was identified as A. alter nata. To our knowledge, this is the first report of A. alternata on leaves of B. gymnorrhiza in China. This pathogen could cause serious foliar damage and threaten the survival, growth, and fitness of the local B. gymnorrhiza community.

Turfgrass grow‐in on sand‐based putting greens usually incurs a high risk for nitrogen (N) leakage. Our objective was to evaluate how substitution of a standard mineral fertilizer with an amino‐acid‐based fertilizer affects creeping bentgrass (Agrostis stolonifera L.) establishment rate and the concentration of nitrate and total N in drainage water. The experiment was conducted from 19 May to 26 July 2016 in the United States Golf Association green field lysimeter facility at Landvik, Norway. The liquid fertilizers arGrow Turf (70% of N as arginine and 30% as lysine) and Wallco (60% of N as nitrate and 40% as ammonium) were applied at ∼2‐wk intervals at the two rates of 1.5 or 3.0 g N m−2 application−1. Results showed significantly faster grow‐in on plots receiving amino‐acid‐based fertilizer than on plots receiving mineral fertilizers; the average turfgrass coverage 26 d after the first fertilization was 75 and 36%, respectively. In parallel with this, the average concentration of nitrate and total N in drainage water, as well as the total N loss, were all reduced by 40 to 45%. Arginine and lysine at 1.5 g N m−2 gave faster grow‐in than Wallco at 3.0 g N m−2 and was the only treatment in which the drainage water complied with EU's requirements for maximum concentration of nitrate in drinking water.

Soil water repellency (SWR) is a common phenomenon on sand-based golf greens. Soils are considered severely water repellent if water droplets remain on the surface of undisturbed, air-dried soil samples for more than 600 seconds before penetrating. The objective of this research was to evaluate the potential of a surfactant to overcome SWR and restore turfgrass quality on a green with severe drought symptoms. The surfactant Aqueduct was applied at a rate of 25 L ha −1 at weekly intervals from 4 June through 25 June 2008, either alone or after aeration with solid tines to 5 cm depth before each application. The experiment was irrigated uniformly corresponding to 1.65 times pan evaporation values from 4 June till 12 June, after which irrigation was not necessary due to natural rainfall. Conspicuous and statistically significant improvements in turfgrass quality occurred 10-12 days after the first application of surfactant, and the difference from untreated control plots continued to increase for about two and a half months after the completion of treatments. The improvement was accompanied by a significant increase in the SWC of the 0-20 cm soil layer and a deeper root system. The difference in WDPT between treated and untreated plots was significant at 1 cm, but not at 2, 3, 5 or 10 cm soil depths which were always far more water repellent than the thatch layer. Repeated aeration had no significant effect on turfgrass quality, and there was no significant interaction between surfactant and aeration treatments.