Turfgrass managers are in need of low‐input turfgrass species options. We have previously identified a number of species that do well as low‐input, sustainable turf in the north central United States. The objective of this study was to evaluate multiple cultivars of turfgrass species with known adaption to low‐input environments in the North Central Region. Twenty‐five turfgrass cultivars and selections, representing ten grass species, were evaluated at eight locations. Plots were established in late summer 2007, and after establishment were maintained at 7.6 cm without inputs of pesticides, fertilizer, or supplemental irrigation. Tall fescue, Chewings fescue, hard fescue, and colonial bentgrass performed well at most locations. Sheep fescue, tufted hairgrass, and prairie junegrass all performed adequately at some locations, and poorly at others. Texas bluegrass hybrids and the single Idaho bentgrass entry were not well adapted to most of the region.
Annual bluegrass (Poa annua L.) may be the most troublesome and studied weed on golf courses in the United States. Given the genetic variability of annual bluegrass and its ability to adapt to different environments, it is important to understand how control methods vary across environments or regions. Our objective was to evaluate seven season‐long regimes of herbicide or growth regulators for annual bluegrass control in creeping bentgrass (Agrostis stolonifera Huds.) putting greens over 3 or 4 years in three states in the midwestern United States. Depending on the product, applications were made as often as every 2 weeks from April through September. Effectiveness of treatments varied widely by location and time, with treatments most effective in Indiana and Nebraska. Paclobutrazol was the most effective plant growth regulator for annual bluegrass control, followed closely by flurprimidol. Intermediate at reducing annual bluegrass was flurprimidol + trinexapac‐ethyl and trinexapac‐ethyl was ineffective. Among herbicides, the now discontinued experimental cumyluron was most effective and four applications of bispyribac‐sodium at 2 oz/acre every 2 weeks in August and September was more effective than 1 oz/acre applied every 2 weeks from May through September or applications of cumyluron. Though a number of products will reduce annual bluegrass on golf greens, overall control was relatively low, reinforcing the need to maximize cultural practices before attempting chemical control. Furthermore, our results reinforce the importance of superintendents’ experimenting and refining treatment regimes in their specific location to maximize efficacy.
Annual bluegrass (ABG) (Poa annua L.) is a prolific seed producer in the spring on golf courses that in turn decreases aesthetic quality and trueness of ball roll on coolseason putting greens. Proxy (ethephon) applied twice in the spring after green-up is the current industry standard after the loss of Embark (mefluidide) from the turf and ornamental market. However, plant growth regulators including Proxy have been used for years to help suppress ABG seedheads with inconsistent success. The primary objective of this study was to determine if ABG seedhead suppression is improved by adding a late fall application of Proxy to the two traditional spring applications of plant growth regulators at nine locations with diverse environments. A second objective was to determine the importance of including Primo Maxx (trinexapac-ethyl) in fall and spring applications. Adding a late fall application of Proxy prior to the two spring applications (F+S+S) improved control of ABG seedheads over the traditional two spring applications (S+S), but the magnitude of improvement varied among locations. Abbreviations: ABG, annual bluegrass; AUSCPC, area under seedhead cover progress curve; CBG, creeping bentgrass; DAISA, days after initial spring application; F+S+S, Proxy + Primo Maxx applied once in fall plus twice in spring; GDD, growing degree day; S+S, Proxy + Primo Maxx applied twice in spring. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
Most research on nitrate‐nitrogen (NO3–N) leaching in turfgrass was conducted on recently established sites and indicates that leaching poses little risk to the environment. The potential for greater NO3–N leaching from mature turf sites is relatively unknown. Nitrogen (N) leaching from a Kentucky bluegrass (Poa pratensis L.) turf was measured for 15 yr using monolith lysimeters. From 1998 through 2002, half of the lysimeters were treated annually with urea at a high rate of 245 kg N ha−1 (49 kg N ha−1 application−1) and half of the lysimeters were treated at a low rate of 98 kg N ha−1 (24.5 kg N ha−1 application−1). Flow‐weighted mean NO3–N concentrations in leachate for the low N rate were below 5 mg L−1 for every year but one of the 15 yr of research. For the high N rate, NO3–N concentrations in leachate for many dates from 2000 through 2002 were higher than the drinking water quality maximum contaminant level of 10 mg L−1. Due to high concentrations of NO3–N in leachate, the high N rate was reduced from 245 to 196 kg ha−1yr−1 in 2003. From 2004 through 2013, there was a decline in NO3–N leaching. For both N rates, the flow‐weighted mean NO3–N concentration in 2013 was less than in 1998, when the research was initiated. This research indicates that, as a turfgrass system ages, there is a critical annual N rate, above which NO3–N concentration in leachate may exceed the maximum contaminant level, and below which there is minimal risk.
Six 1-yr observational studies were conducted from 2001 to 2006 at the Hancock Turfgrass Research Center in East Lansing, MI to characterize the timing, duration, and amplitude of annual bluegrass (AB) (Poa annua L.) seedhead emergence in a 10-to 15-yr-old AB fairway. The objective of this research was to collect data that could be used in the development of a growing degree-day (GDD) model to predict AB seedhead emergence at other locations by using readily available weather station data. New GDD models were compared with previously published models. Plots were established on two adjacent perennial stands of AB maintained at 1.5 cm, receiving 0.5 to 0.6 cm of automatic daily irrigation throughout the growing season and 120 kg N ha -1 yr -1 from 2001 to 2006. The soil type is a Marlette sandy loam (fine-loamy, mixed, semiactive, mesic Oxyaquic Glossudalf). Line intersects and visual estimations of seedhead cover were evaluated multiple times throughout the spring seedhead emergence period. A base temperature of -5 ˚C most accurately predicted the onset, peak duration, and completion of the AB seedhead emergence period for all 5 yr. The final model flowering rate = (-3.331599 × 10 -6 × gdd 2) + (6.968782 × 10-3 × gdd) + -2.841894, accurately predicted (R 2 = .64) flowering stages of an AB fairway turf over 6 yr in Michigan.
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