Brian P. Horgan

Phosphorus runoff from turfgrass as affected by phosphorus fertilization and clipping management.

Phosphorus enrichment of surface water is a concern in many urban watersheds. A 3-yr study on a silt loam soil with 5% slope and high soil test P (27 mg kg(-1) Bray P1) was conducted to evaluate P fertilization and clipping management effects on P runoff from turfgrass (Poa pratensis L.) under frozen and nonfrozen conditions. Four fertilizer treatments were compared: (i) no fertilizer, (ii) nitrogen (N)+potassium (K)+0xP, (iii) N+K+1xP, and (iv) N+K+3xP. Phosphorus rates were 21.3 and 63.9 kg ha(-1) yr(-1) the first year and 7.1 and 21.3 kg ha(-1) yr(-1) the following 2 yr. Each fertilizer treatment was evaluated with clippings removed or clippings recycled back to the turf. In the first year, P runoff increased with increasing P rate and P losses were greater in runoff from frozen than nonfrozen soil. In year 2, total P runoff from the no fertilizer treatment was greater than from treatments receiving fertilizer. This was because reduced turf quality resulted in greater runoff depth from the no fertilizer treatment. In year 3, total P runoff from frozen soil and cumulative total P runoff increased with increasing P rate. Clipping management was not an important factor in any year, indicating that returning clippings does not significantly increase P runoff from turf. In the presence of N and K, P fertilization did not improve turf growth or quality in any year. Phosphorus runoff can be reduced by not applying P to high testing soils and avoiding fall applications when P is needed.

Low-Input Turfgrass Species for the North Central United States

Public attention is being increasingly focused on the environmental impact and management costs of turfgrass areas such as lawns for schools, parks, and homes. The objectives of this study were to: (i) identify grass species adapted to low-input environments (limited water, no fertilizer or pesticides after establishment) in the North Central Region (NCR) of the USA; and (ii) evaluate these species for turfgrass quality under mowed and non-mowed conditions. Lowinput turf trials of 12 grass species were established at eight locations and evaluated for turf quality over two years. Plots were mowed monthly at either 5.1 or 10.2 cm or not mowed. Hard fescue (Festuca brevipila Tracey), colonial bentgrass (Agrostis capillaris L.), tall fescue (Festuca arundinacea Schreb.), and sheep fescue (Festuca ovina L.) performed well at most locations at the 5.1 and 10.2-cm mowing heights. Several other species were also evaluated: tufted hairgrass [Deschampsia cespitosa (L.) P. Beauv.], hybrid bluegrass (Poa arachnifera Torr. × Poa pratensis L.), meadow fescue [Schedonorus pratensis (Huds.) P. Beauv.], prairie junegrass [Koeleria macrantha (Ledeb.) Schult], crested wheatgrass [Agropyron cristatum (L.) Gaertn.], alkaligrass [Puccinellia distans (Jacq.) Parl.], blue grama [Bouteloua gracilis (Willd. Ex Kunth) Lag. Ex Griffiths], and crested dogstail (Cynosurus cristatus L.). Introduction At present, Kentucky bluegrass (Poa pratensis L.), perennial ryegrass (Lolium perenne L.), and tall fescue are the primary species used for turf in the North Central Region (NCR). Recently-developed Kentucky bluegrass and perennial ryegrass cultivars provide high quality turf when managed with sufficient amounts of fertilizers, water, and pesticides (21). However, there has been increasing attention drawn to the negative aspects of higher input turfs (15) which has resulted in changes such as fertilizer use restrictions in Minnesota (19), cosmetic pesticide restrictions in Canada (9), and water use restrictions set by the Environmental Protection Agency (23). Current turf management options and some of the species and cultivars commonly used for turf may be inadequate for use in the USA in the future due to potential negative impacts of high-input turfgrass management on the environment. One way to reduce inputs is by identifying and planting low-input turfgrass species that require less mowing, fertilization, and irrigation in order to achieve adequate visual quality. In order to use low-input species and make them attractive to the 26 January 2011 Applied Turfgrass Science public, it is critical to properly assess low-input adaptation across multiple environments. Diesburg et al. (6) evaluated twelve grass species as low-input turf at seven sites in the NCR for three years. Overall, the best performing species, as determined by plot uniformity and cover, were tall fescue, colonial bentgrass, redtop bentgrass (Agrostis gigantea Roth), and sheep fescue. We decided to compare the performance of some species that did well in the study by Diesburg et al. (tall fescue, colonial bentgrass, sheep fescue) with other grasses that have been shown to be effective in climates similar to the NCR and with grasses that have not been extensively tested for low-input turf but have shown the potential to perform adequately in the NCR. Hard fescue is a bunch-type grass native to central Europe known to perform well in reduced-input shady environments, under full-sun conditions, and in situations where reduced mowing frequency is desirable (10,17). Tufted hairgrass is a cool-season bunch grass that can thrive in both sun and shade when moisture is not limiting (3). Prairie junegrass is native to the Great Plains and has performed adequately in low-input turf evaluations in Canada (16). Blue grama is a warm-season bunchgrass found throughout the Great Plains that has shown potential for use as a turf in low-nitrogen and arid environments (13,16). In recent years, a number of Texas bluegrass × Kentucky bluegrass hybrid cultivars have been released; these cultivars can exhibit improved heat tolerance compared to Kentucky bluegrass (20). Other species that have not been tested on a wide-scale in the NCR include alkaligrass, which can be an effective turf when grown in areas with high salt levels in the soil (21); meadow fescue, which is similar in appearance to coarse-textured tall fescue cultivars (1); crested wheatgrass, a grass that has been the focus of germplasm improvement efforts for use in arid environments (11); and crested dogstail, which has been shown to be adapted to shady environments (14). The objectives of this study were to: (i) identify grass species adapted to lowinput environments (limited water, no fertilizer or pesticides after establishment) in the NCR of the USA; and (ii) evaluate these species for turfgrass quality under mowed and non-mowed conditions. These low-input grasses could potentially be utilized on home lawns, school grounds, parks, golf course roughs, and other turf areas. Furthermore, the identification of species with potential low-input use will give plant breeders information to help focus germplasm improvement programs. Establishment and Treatments In fall 2004, 12 grass species (Table 1) were seeded at eight sites in the NCR (Table 2). The experimental design for each location was a split plot with mowing height as the main plot and species as the sub-plot. Individual subplots were 1.52 m × 0.91 m, with no border between plots, and seeded at a generally-accepted rate for each species (Table 1). Plots were established by either dormant seeding or a typical late summer seeding on bare soil (Table 2). Dormant seeding was done late-fall once soil temperatures were below 5°C to ensure that seed would not germinate until temperatures warmed in the spring. After seed was applied and lightly raked into the soil, the dormant-seeded trials were covered with Futerra blankets (Profile Products LLC, Buffalo Grove, IL). Late summer-seeded plots were seeded in late August/early September and a starter fertilizer was used at time of seeding at a rate of approximately 49 kg N/ha and 43 kg P O /ha. Plots were irrigated during the fall establishment period. Following establishment, no irrigation or fertilizer was applied. For both establishment methods, during the first spring after seeding, broadleaf weeds were controlled with a single application of an herbicide mixture of 2,4-D, MCPP, and dicamba (Trimec Classic, PBI/Gordon Corp., Kansas City, MO) at all sites with the exception of Wisconsin (no herbicide applied), North Dakota (no herbicide applied), and Ohio [single application of an herbicide mixture of 2,4D, clopyralid, and dicamba (Millennium Ultra 2, Nufarm Americas Inc., Burr Ridge, IL)]. No other pesticides were ever applied at any location. Beginning in spring 2005, three mowing treatments were applied: (i) once per month at 2 5 26 January 2011 Applied Turfgrass Science 5.1 cm; (ii) once per month at 10.2 cm; and (iii) no mowing. Plots were mowed with a rotary mower and clippings were returned. Table 1. Turfgrass entries planted at 8 locations in the North Central United States in 2004 for the low-input turfgrass study. Table 2. Seeding method, weather information, soil type, and pH for research sites. x Total precipitation from 1 April through 31 October. Data Collection and Analysis Turfgrass quality was assessed monthly during each growing season using visual ratings on a 1 to 9 scale, with 9 representing the best turfgrass quality. Persistence (plot cover) and uniformity were the two primary criteria used to determine quality for each plot. Secondary criteria included freedom from disease and insect damage, color, and turf density. A rating of 5.0 was considered to be acceptable turf. All data were subjected to analysis of variance according to the general linear models procedure of SAS (SAS Institute Inc., Cary, NC). The yearly turf quality averages for all locations and years were combined in an analysis of variance which showed that location and all year by interactions were significant at the P ≤ 0.0001 level. Therefore, yearly turfgrass quality averages at each location were analyzed separately. Species turfgrass quality means (within mowing treatment at each location) were separated by Fisher’s Least Significant Difference (LSD) test at P ≤ 0.05. The effect of species (cultivar) was highly significant at all locations while the effect of mowing and the cultivar × mowing interaction was Common name Scientific name Cultivar or selection Seeding rate (g/m2) Alkaligrass Puccinellia distans Fults 7.3 Blue grama Bouteloua gracilis Bad river 14.7 Colonial bentgrass Agrostis tenuis SR 7150 4.9 Crested dogstail Cynosurus cristatus ShadeStar 4.9 Crested wheatgrass Agropyron cristatum Roadcrest 24.4 Hard fescue Festuca trachyphylla Berkshire 29.3 Meadow fescue Schedonorus pratensis LMC-1122 34.2 Prairie junegrass Koeleria macrantha LMC-5000 9.8 Sheep fescue Festuca ovina Blacksheep 34.2 Tall fescue Festuca arundinacea Grande II 34.2 Texas bluegrass hybrid Poa arachnifera × Poa pratensis DuraBlue 9.8 Texas bluegrass hybrid Poa arachnifera × Poa pratensis HB 342 9.8 Tufted hairgrass Deschampsia cespitosa Spike 4.9 Location Establishment method Rainfall (mm) Soil Type pH 2005 2006 Ames, IA fall 566 735 loam 7.6 West Lafayette, IN fall 480 763 silt loam 7.8 East Lansing, MI fall 388 544 fine loam 7.8 St. Paul, MN dormant 832 681 silt loam 7.6 Fargo, ND fall 571 341 silty clay 7.8 Columbus, OH dormant 547 776 loam 7.4 Brookings, SD dormant 773 561 clay loam 7.7 Madison, WI dormant 390 746 silt loam 7.5 x 26 January 2011 Applied Turfgrass Science sometimes significant depending on location (Table 3). Cultivar data from each location were analyzed separately for each year at each location for each of the three mowing heights (Tables 4 to 6). Table 3. Analysis of variance (P > F) for average turfgrass quality at eight locations in the North

Evaluation of core cultivation practices to reduce ecological risk of pesticides in runoff from Agrostis palustris

Pesticides associated with the turfgrass industry have been detected in storm runoff and surface waters of urban watersheds, invoking concern of their potential environmental effects and a desire to reduce their transport to nontarget locations. Quantities of chlorpyrifos, dicamba, dimethylamine salt of 2,4-dichlorophenoxyacetic acid (2,4-D), flutolanil, and mecoprop-p (MCPP) transported in runoff from bentgrass (Agrostis palustris) fairway turf managed with solid tine (ST) or hollow tine (HT) core cultivation were compared to determine which cultivation practice is more efficient at mitigating environmental risk. Plots receiving HT core cultivation showed a 10 and 55% reduction in runoff volume and a 15 to 57% reduction in pesticide transport with runoff at 63 d and 2 d following core cultivation. Estimated environmental concentrations of the pesticides in a surface water receiving runoff from turf managed with ST core cultivation exceeded the median lethal concentration (LC50) or median effective concentration (EC50) of nine aquatic organisms evaluated. Replacing ST core cultivation with HT core cultivation reduced surface water concentrations of the pesticides to levels below the LC50 and EC50 for most these aquatic organisms, lessening risk associated with pesticides in runoff from the fairway turf. Results of the present research provide quantitative information that will allow for informed decisions on cultural practices that can maximize pesticide retention at the site of application, improving pest control in turf while minimizing environmental contamination and adverse effects associated with the off-site transport of pesticides.

Use of Diffusion to Determine Soil Cation-Exchange Capacity by Ammonium Saturation

Abstract Soil cation-exchange capacity (CEC) is often determined by NH4 saturation, using a 1 M solution of NH4C2H3O2 at pH 7. A study was conducted to ascertain whether this determination can be performed by employing a simple diffusion technique previously developed for direct inorganic-N analysis of soils. Values obtained for 10 diverse Illinois surface soils following overnight NH4 saturation were correlated very highly with CEC data collected for the same samples on the basis of NH4 analyses by steam distillation (r = 0.999, P < 0.001) or colorimetry (r = 0.999, P < 0.001), and also with data obtained by summing atomic absorption measurements of calcium (Ca), magnesium (Mg), and potassium (K) displaced during NH4 saturation (r = 0.811, P < 0.01). As a much more rapid and convenient alternative to existing methods for preparation of NH4-saturated soil, a simple saturation technique was developed whereby 0.500 g of soil was leached under vacuum with 15 mL of 1 M NH4C2H3O2 (pH 7) in a 10-mL disposable syringe containing a stainless-steel frit, and then with 30 mL of 2-propanol. After drying for a few minutes, the soil sample was transferred to a 473-mL (1-pint) wide-mouth Mason jar, treated with 10 mL of 2 M KCl, and analyzed for exchangeable NH4 by diffusion with MgO for 1.75 h at 45–50°C on a hot plate. Except for a calcareous soil, CEC measurements by the rapid saturation-diffusion approach did not differ significantly (P < 0.05) from diffusion data involving overnight NH4 saturation. This approach allows CEC determinations to be accomplished in a few hours instead of days, and will be especially useful for routine soil characterization and testing.

Pesticide transport with runoff from creeping bentgrass turf: Relationship of pesticide properties to mass transport

The off-site transport of pesticides with runoff is both an agronomic and environmental concern, resulting from reduced control of target pests in the area of application and contamination of surrounding ecosystems. Experiments were designed to measure the quantity of pesticides in runoff from creeping bentgrass (Agrostis palustris) turf managed as golf course fairway to gain a better understanding of factors that influence chemical availability and mass transport. Less than 1 to 23% of applied chloropyrifos, flutolanil, mecoprop-p (MCPP), dimethylamine salt of 2,4-dichlorophenoxyacetic acid (2,4-D), or dicamba was measured in edge-of-plot runoff when commercially available pesticide formulations were applied at label rates 23 +/- 9 h prior to simulated precipitation (62 +/- 13 mm). Time differential between hollow tine core cultivation and runoff did not significantly influence runoff volumes or the percentage of applied chemicals transported in the runoff. With the exception of chlorpyrifos, all chemicals of interest were detected in the initial runoff samples and throughout the runoff events. Chemographs of the five pesticides followed trends in agreement with mobility classifications associated with their soil organic carbon partition coefficient (K(OC).) Data collected from the present study provides information on the transport of chemicals with runoff from turf, which can be used in model simulations to predict nonpoint source pollution potentials and estimate ecological risks.

Salt tolerance of 75 cool-season turfgrasses for roadsides

Abstract Roadside vegetation is subject to significant salt stress as a result of runoff water and road de-icing practices in cold weather climates. Salt-tolerant turfgrass can play a role in maintaining roadsides that are both functional and sustainable. As such, the objective of this research was to evaluate the differential salt tolerance of turfgrass cultivars that may be suitable for roadside establishment. Three replications of 75 cool-season turfgrass cultivars were established in a randomized complete block design at two locations: Roselawn Cemetery (Roseville, MN, USA) and MnROAD research facility (Albertville, MN, USA). Plots were seeded during August and September of 2010. Visual ratings of establishment were collected throughout the fall, and survival was evaluated visually in spring 2011. Numerous cultivars of perennial ryegrass (Lolium perenne L.) established best at all locations in the fall; however, winter survival varied by location. Cultivars of alkaligrass (Puccinellia spp.), including ‘Fults,’ ‘Salty,’ ‘Oceania,’ and ‘Salton Sea,’ performed best at Albertville. ‘Shoreline’ slender creeping red fescue (Festuca rubra L. ssp. litoralis), ‘Navigator’ strong creeping red fescue (Festuca rubra L. ssp. rubra), and an advanced population of sheep fescue (Festuca ovina L.) from the University of Minnesota turfgrass breeding program were among the most salt tolerant at Roseville. Site-dependent performance and effective salt tolerance of cultivars from numerous species indicate that a carefully chosen mix will be best for establishment and maintenance of high-quality roadsides.

Nutrient loss with runoff from fairway turf: an evaluation of core cultivation practices and their environmental impact.

The presence of excess nutrients in surface waters can result in undesirable environmental and economic consequences, including nuisance algal blooms and eutrophication. Fertilizer use in highly managed turf systems has raised questions concerning the contribution of nutrients to surrounding surface waters. Experiments were designed to quantify phosphorus and nitrogen transport with runoff from turf plots maintained as a golf course fairway to identify which cultural practice, solid tine (ST) or hollow tine (HT) core cultivation, maximized phosphorus and nitrogen retention at the site of fertilizer application. Simulated precipitation and collection of resulting runoff were completed 26 ± 13 h following granular fertilizer application (18-3-18: N-P₂O₅-K₂O) and 63 d and 2 d following core cultivation. Runoff volumes were reduced in fairway turf plots aerated with HT relative to ST (63 d: 10%, 2 d: 55% reduction). Analysis of the runoff revealed a reduction in soluble phosphorus, ammonium nitrogen, and nitrate nitrogen losses with runoff from plots managed with HT; a 5 to 27% reduction after 63 d; and a 39 to 77% reduction at 2 d. Golf course runoff-to-surface water scenarios were used to calculate estimated environmental concentrations (EECs) of nitrogen and phosphorus in surface water receiving runoff from turf managed with ST or HT core cultivation. Surface water concentrations of phosphorus remained above the U.S. Environmental Protection Agencys water quality criteria to limit eutrophication, with the exception of concentrations associated with HT core cultivation at 2 d. Regardless of management practice (ST or HT) and time between core cultivation and runoff (63 d or 2 d), all EECs of nitrogen were below levels associated with increased algal growth. Understanding nutrient transport with runoff and identifying strategies that reduce off-site transport will increase their effectiveness at intended sites of application and minimize undesirable effects to surrounding surface water resources.

Evaluation of nitrogen and phosphorus transport with runoff from fairway turf managed with hollow tine core cultivation and verticutting

Enrichment of surface waters with excess nutrients is associated with increased algal blooms, euthrophication and hypoxic zones, as reported in the northern Gulf of Mexico. A source of nutrients to surface waters results from fertilizer runoff. Management strategies used to maintain turf on golf courses and recreational fields often include aerification and application of fertilizer. Although research exists on benefits of core cultivation and verticutting (VC) to reduce thatch and the transport of applied chemicals with runoff, there are no studies reporting the effect of coupling these management practices with the goal of further reduction of off-site transport of fertilizer with runoff. We hypothesized that the addition of VC to hollow tine core cultivation (HTCC) would enhance infiltration of precipitation, reduce runoff and nutrient transport with runoff and therefore influence concentrations of nutrients in surface waters receiving runoff from turf managed as a golf course fairway. Greater runoff and mass of soluble phosphorus and ammonium nitrogen transported with runoff were measured from plots managed with HTCC+VC than HTCC; however, the reverse was noted for nitrate nitrogen. Only a portion of the observed trends proved to be statistically significant. Our research showed no reduction or enhancement of risk associated with surface water concentrations of phosphorus or nitrogen, resulting from runoff from creeping bentgrass turf that was managed with HTCC+VC compared to HTCC. Data obtained in this research will be useful to grounds superintendents when selecting best management practices and to scientists seeking data relating runoff to land management for watershed-scale modeling.

Conversion of Kentucky Bluegrass Rough to No-Mow, Low-Input Grasses

Golf courses have become a large part of the environmental landscape today. The land area needed for golf is larger than any other sport and the United States alone has nearly 17,000 golf courses with the North Central Region having the highest concentration with 4,238 [6,11]. There are many scientific studies that have detailed the benefits of turfgrass. However, the use of water, fertilizer and pesticides in maintaining golf courses continues to come under fire for not being environmentally friendly and unnatural to the landscape. Golf courses and their turfgrass managers realize the need for continuing to decrease the inputs needed to run a golf course, not only from an environmental standpoint but also a monetary standpoint. Golf course superintendents have become highly educated professionals that continue to adapt their management practices in order to reduce the environmental impact of their golf course. Golf course rough is the largest percentage of maintained turf area of a golf course comprising 52% of the total maintained area [8]. Of this rough area, the most common turfgrass species planted in the North Central region of the United States is Kentucky bluegrass, accounting for 63% of the rough area. Under high management, Kentucky bluegrass is very aesthetically pleasing and provides a high quality playing surface that can recover from divots caused by golfers. However, inputs required to maintain playing conditions in golf course settings are often high. Kentucky bluegrass has a large demand for water to prevent dormancy from drought and a high need of fertilizer to maintain turfgrass color and quality [3]. Due to these high inputs of water and fertilizer, golf course rough generally needs to be mowed two times per week which increases labor, machinery costs, and fuel budgets. In addition, weeds are often controlled with herbicides adding to the inputs needed to maintain the quality of the largest area on a golf course. The combination of large amounts of established Kentucky bluegrass rough and inputs required to maintain its playing quality have prompted many golf courses to question the need for heavily maintaining their Kentucky bluegrass rough areas. Many golf courses are now considering the conversion of these high-input rough areas to no-mow, low-input grasses. There were two objectives to this study: (1) to compare several methods for converting Kentucky bluegrass rough to no-mow, low-input grasses and (2) to then determine the best turfgrass species for use in conversion. Conversion of Kentucky bluegrass rough to no-mow, low-input grasses is a relatively new topic. Although very few studies have focused on converting Kentucky bluegrass rough to no-mow grasses, some have focused on which species may perform well in low-input situations. Studies have found that fine fescues are more drought tolerant, require less fertility, have higher resistance to weed invasion in low-input situations, and have better stand quality in no-mow situations than does Kentucky bluegrass [1,2,4,5,7,12].

Pesticide Transport with Runoff from Turf: Observations Compared with TurfPQ Model Simulations

Pesticides applied to turf grass have been detected in surface waters raising concerns of their effect on water quality and interest in their source, hydrological transport and use of models to predict transport. TurfPQ, a pesticide runoff model for turf grass, predicts pesticide transport but has not been rigorously validated for larger storms. The objective of this study was to determine TurfPQs ability to accurately predict the transport of pesticides with runoff following more intense precipitation. The study was conducted with creeping bentgrass [Agrostis palustris Huds.] turf managed as a golf course fairway. A pesticide mixture containing dicamba, 2,4-D, MCPP, flutolanil, and chlorpyrifos was applied to six adjacent 24.4 by 6.1 m plots. Controlled rainfall simulations were conducted using a rainfall simulator designed to deliver water droplets similar to natural rain. Runoff flow rates and volume were measured and water samples were collected for analysis of pesticide concentrations. Six simulations yielded 13 events with which to test TurfPQ. Measured mean percentage of applied pesticide recovered in the runoff for dicamba, 2,4-D, MCPP, flutolanil, and chlorpyrifos was 24.6, 20.7, 14.9, 5.9, and 0.8%, respectively. The predicted mean values produced by TurfPQ were 13.7, 15.6, 15.5, 2.5, and 0.2%, respectively. The model produced correlations of r=0.56 and 0.64 for curve number hydrology and measured hydrology, respectively. Comparisons of the model estimates with our field observations indicate that TurfPQ under predicted pesticide runoff during 69.5+/-11.4 mm, 1.9+/-0.2 h, simulated storms.