Alexander R. Kowalewski

Improving native soil athletic fields with intercept drain tile installation and subsequent sand topdressing applications

Intercept drain tile installation and subsequent sand topdressing applications can provide a built-up sand-based system. There are a number of different intercept drain tile spacing and sand layer depth recommendations. The objectives of this research were to determine the effects of intercept drain tile spacing on the surface runoff, soil water content, and surface shear strength of a compacted sandy loam with sand topdressing. A single factor, RCBD field study in East Lansing, Michigan, was seeded May 29, 2007, with a Kentucky bluegrass (Poa pratensis L.)-perennial ryegrass (Lolium perenne L.) mixture. Intercept drain tiles were spaced 2.0, 3.0, 4.0, and 6.0 m apart and were compared with an 8.1-m-long control without intercept drain tiles. Well-graded sand (90.0% sand, 7.0% silt, and 3.0% clay) was used for topdressing. After the accumulation of a 2.4-cm sand layer, simulated traffic at two applications per week was applied to all treatments using the Cady traffic simulator from October 10 to November 3, 2007. In 2008, topdressing, providing a 4.8-cm depth accumulated during a 2-year period, and traffic were repeated on the same experimental treatments. When a 2.4-cm sand layer is present, surface runoff and soil water content are generally directly related to intercept drain tile spacing, and drain tiles, spaced 2.0, 3.0, and 4.0 m apart, will provide increased surface shear strength. As topdressing depths were accumulated to a 4.8-cm sand layer depth in 2008, no differences in surface shear strength were observed regardless of drain tile spacing.

Evaluating Hybrid Bermudagrass Using Spectral Reflectance under Different Mowing Heights and Trinexapac-ethyl Applications

Quantitative spectral reflectance data have the potential to improve the evaluation of turfgrasses in variety trials when management practices are factors in the testing of turf aesthetics and functionality. However, the practical application of this methodology has not been well developed. The objectives of this research were 1) to establish a relationship between spectral reflectance and turfgrass quality (TQ) and percent green cover (PGC) using selected reference plots; 2) to compare aesthetic performance (TQ, PGC, and vegetation indices) and functional performance (surface firmness); and 3) to evaluate lignin content as an alternate means to predict surface firmness in turfgrass variety trials of hybrid bermudagrass [Cynodon dactylon ·C. transvaalensis]. A field study was conducted on mature stands of three varieties (‘TifTuf’, ‘TifSport’, and ‘Tifway’) and two experimental lines (04-47 and 04-76) at two mowing heights (0.5 and 1.5 inch) and trinexapac-ethyl application (0.15 kg ha and nontreated control) treatments. Aesthetic performance was estimated by vegetation indices, spectral reflectance, visual TQ, and PGC. The functional performance of each variety/line was measured through surface firmness and fiber analysis. Regression analyses were similar when using only reference plots or all the plots to determine the relationship between individual aesthetic characteristics. Experimental line 04-47 had lower density in Apr. 2010, whereas varieties ‘TifTuf’, ‘TifSport’, and ‘Tifway’ were in the top statistical group for aesthetic performance when differences were found. ‘TifSport’ and ‘Tifway’ produced the firmest surfaces, followed by ‘TifTuf’, and finally 04-76 and 04-47,which provided the least firm surface. Results of leaf fiber analysis were not correlated with turf surface firmness. This study indicates that incorporating quantitative measures of spectral reflectance could reduce time and improve precision of data collection as long as reference plots with adequate range of green cover are present in the trials.

Using cultural practices and leaf mulch to control weeds in established turfgrass.

Recent research has shown that leaves collected from a variety of tree species mulched into established turfgrass resulted in fewer common dandelions (Taraxacum officinale W.). However, the turfgrass in this research was managed at a low maintenance level to promote weed establishment. An experiment was initiated in October 2004 to develop a better understanding of how mulched leaves would effect dandelion populations in properly maintained turfgrass. The objective of this research was to quantify the effectiveness of leaf mulch as an organic weed control method when combined with frequent nitrogen fertilizer applications and a mowing height conducive to a cool-season turfgrass mixture. Research was initiated on 21 October 2004 in East Lansing, MI, on a sandy loam soil without irrigation. Main effects included leaf species, fertilization, and mowing height. Leaf species were sugar maple (Acer saccharum M.) and red maple (A. rubrum L.) applied at 1.5 kg/m2, and a control. Fertilization included urea (46.0N0.0P-0.0K) applied at 146.4 kg N per ha annually and a control. Mowing heights were 3.8 cm and 7.6 cm. Data collected in 2005 and 2006 included visual turfgrass quality (1-9 scale, 6 or greater acceptable), percent (0-100%) crabgrass (Digitaria spp.) cover and dandelion counts (dandelions per 10.2 m2). Fertilization increased turfgrass quality and the 3.8-cm mowing height increased crabgrass populations. Regarding dandelion populations, results obtained in 2005 indicate that mulched leaves, regardless of maple species, reduced dandelion counts by up to 84% after a single application. However, after a second leaf mulch application was made in 2005, there was no measured effect on dandelion populations in 2006. Leaf Mulch as an Alternative Weed Control Method Growing concern for environmental safety has urged researchers to explore organically derived weed control methods in the field of turfgrass management (1,14,17). Research conducted by Kowalewski et al. (11) and Nikolai et al. (13) has shown that fallen tree leaves, collected from maple and oak (Quercus spp.) species, mulched into established turfgrass as a leaf litter disposal method resulted in increased spring green-up and fewer common dandelions without producing any deleterious effects (Figs. 1 and 2). However, the Kentucky bluegrass (Poa pratensis L.) stand in the research conducted by Kowalewski et al. (11) was maintained with minimal inputs (no irrigation and low fertilization) and was regularly scalped to promote weed establishment, resulting in extremely high dandelion populations throughout the study and an eventual loss in differences. These findings suggest that mulched leaves alone cannot be used to provide high-end long-term weed control in poorly maintained turfgrass. 16 April 2010 Applied Turfgrass Science In response to these findings, a new experiment was initiated to develop a better understanding of how mulched tree leaves would affect dandelion populations in properly maintained cool-season turfgrass. The objective of this research was to quantify the efficacy of leaf mulch as an organic weed control method when combined with frequent nitrogen fertilizer applications and a mowing height conducive to a cool-season turfgrass mixture. The original hypothesis of this research was that leaf mulch applications, regardless of species, in combination with regular nitrogen fertilizer applications and an increased mowing height, would provide a well integrated turfgrass management system capable of providing long-term dandelion suppression. Project Design A field experiment was initiated 21 October 2004 at the Hancock Turfgrass Research Center (HTRC), East Lansing, MI, to examine the effects of leaf mulch, mowing height and nitrogen fertilizer applications on an established cool-season turfgrass stand. Experimental design was a 3 × 2 × 2 factorial, completely randomized, with three replications. Total experimental area was 572.3 m2, containing 36 treatments (3.0 m wide × 3.4 m long). Factors included tree leaf species (sugar maple and red maple, compared to a control), fertilizer (146.4 kg N per ha applied annually and a control), and mowing height (3.8 and 7.6 cm). Research was conducted on a sandy loam soil [62.5% sand (0.05 to 2.0 mm), 23.3% silt (0.002 to 0.05 mm) and 14.2% clay (< 0.002 mm); MSU Soil and Plant Nutrient Laboratory, East Lansing, MI], with a well established coolseason turfgrass mixture, chewings fescue (Festuca rubra L. var. commutata) (19.6% ‘Moxie’ and 19.5% ‘Raymond’), Kentucky bluegrass (19.6% ‘Ronde,’ 9.8% ‘Cannon,’ and 9.8% ‘Gnome’), and perennial ryegrass (Lolium perenne L.) (9.8% ‘ASP410’ and 9.7% ‘SR4200’), seeded in 1998. A composite soil sample was collected from the research area and used to assess existing soil pH and soil nutrient levels (soil pH 7.4, phosphorus 31.0 mg/kg, and potassium 182.0 mg/kg). This research area was selected because it did not have irrigation, a common practice utilized in low-maintenance turf sites (6),and a situation that home owners across the United States of America could face as water use regulations intensify (2,7). A three-way broadleaf herbicide, 2,4-D (2,4-dichlorophenoxyacetic acid), clopyralid (3,6-dichloro-2-pyridinecarboxylic acid), and dicamba (3,6-dichloroo-anisic acid) (Millennium Ultra2; Nufarms Americas Inc., Burr Ridge, IL) applied at a rate of 1.26, 0.08, and 0.16 kg ai/ha, respectively, was administered on 21 October 2004. This application provided an experimental site free of broadleaf weeds so the preemergence activity of leaf mulch could be evaluated. Fig. 1. Effects of sugar maple leaf mulch (applied at 1.5 kg/m2 on 16 November 2004) on common dandelion populations in established Kentucky bluegrass observed by Kowalewski et al. (11), 8 May 2005, East Lansing, MI. Fig. 2. Effects of no leaf mulch (control) on common dandelion populations in established Kentucky bluegrass observed by Kowalewski et al. (11), 8 May 2005, East Lansing, MI. 16 April 2010 Applied Turfgrass Science Leaf Mulch Collection and Application (2004) Freshly fallen deciduous tree leaves were collected at the W.K. Kellogg Experimental Forest (Augusta, MI) from monoculture, pesticide-free stands of red and sugar maple on 13 November 2004. A lawn blower/vacuum (Poulan PRO #BMV-200 Gas Blower/Vac; Electrolux Home Products, Nashville, AR) was used to collect the leaves. The leaves were transported to the HTRC where they were later applied to the experimental site as mulch. On 19 November 2004, prior to leaf mulch application, dandelion (Taraxacum officinale W.) seed (V & J Seed, Woodstock, IL) was evenly spread over the experimental site to increase the seed bank level of broadleaf weeds. Dandelion seeds were applied at a rate of 2716.0 seeds/m2, equivalent to approximately 2.3 actively seeding dandelions per square meter (15). The Michigan Department of Agricultural Control Laboratory (East Lansing, MI) determined a germination rate of 5.0% using a 21-day germination test with a daily cycle of 16 h at 20.0°C and 8 h at 30.0°C, conforming to the Association of Official Seed Analysts rules for testing dandelion (Association of Official Seed Analysts, 2002). Later that day, tree leaves, with a particle size ranging from 2.5 to 6.4 cm2, were applied at rate of 1.5 kg/m2 (dry weight), a leaf mulch application rate derived from Kowalewski et al. (11). The tree leaves were then incorporated into the turfgrass canopy using a rotary push mower set at a 5.1cm mowing height (Fig. 3). Fertilization and Mowing (2005) Nitrogen applications and two mowing heights were maintained throughout the 2005 growing season. Fertilization treatments totaled 146.4 kg N per ha annually. To achieve these annual rates, urea (46.0N-0.0P-0.0K) (Andersons, Maumee, OH) was applied on 30 May 2005 (48.8 kg N per ha), 4 July 2005 (24.4 kg N per ha), 5 September 2005 (24.4 kg N per ha), and 24 November 2005 (48.8 kg N per ha) using a shaker jar, similar to the experimental design used by Calhoun et al. (4). This was compared to control treatments, which did not receive any fertilizer. Mowing was maintained at two different heights, 3.8 cm and 7.6 cm, using a rotary mulching mower during the 2005 growing season, 28 April to 21 November 2005. Leaf Mulch Collection and Application (2005), Fertilization and Mowing (2006) The same treatments received a second consecutive application of sugar and red maple leaves, collected from the same monoculture stands, in the fall of 2005. Leaves were collected on 3 November 2005 at the W.K. Kellogg Experimental Forest, transported to East Lansing, applied at the same application rate, 1.5 kg/m2, and mowed into the turfgrass canopy on 19 November 2005. Experimental treatments that received fertilizer in 2005 were again fertilized on 31 May 2006 (48.8 kg N per ha), 4 July 2006 (24.4 kg N per ha), 4 September 2006 (24.4 kg N per ha), and 25 November 2006 (48.8 kg N per ha) with urea. The treatments were maintained at the previously specified Fig. 3. Sugar maple leaves being mulching into an established Kentucky bluegrass stand, November 19, 2005, East Lansing, MI. 16 April 2010 Applied Turfgrass Science mowing heights throughout the 2006 growing season, 28 April to 18 November 2006. Data Collection (2005 and 2006) Turfgrass quality, crabgrass cover (0 to 100%), and dandelion populations (dandelions per 10.2 m2) were evaluated after the first leaf mulch application on 17 August 2005 and again after the second leaf mulch application on 10 August 2006. Turfgrass quality was based on the National Turfgrass Evaluation Program (NTEP) system of rating, 1 being the poorest possible or dead, 9 being perfect or ideal turfgrass and 6 or greater being acceptable (12). Statistical Analysis Data were analyzed as a factorial, completely randomized design with three replications using Agricultural Research Management (ARM) (8). The three studied factors included tree leaf species (red maple, sugar maple and control), n