Mowing Strategies and Fertilization Improves Sports Fields During and After 70-day Re-establishment Window

J. Tim Vanini, New Dimensions Turf Inc., Buffalo, NY 14216; and John N. Rogers, III, Crop and Soil Sciences, Michigan State University, East Lansing 48824

Corresponding author: J. Tim Vanini. ndturf@mac.com

Abstract

Little information exists for sports field managers on optimal ways to re-establish trafficked areas on a sports field during a 70-day window. A 2002 Michigan Rotational Survey reported two cultural practices sports field managers performed most consistently, regardless of maintenance level, were mowing and fertility. A study was conducted at Michigan State University in 2002 and 2003. Objectives were to (i) clarify the impact of best management practices in regards to mowing height and fertilization on re-establishment of sports field turf during a 70-day window, and (ii) quantify these effects during and after a 25-day simulated traffic period. Data collected were turfgrass cover percent ratings, traction, and peak deceleration. The gradually reducing mowing height treatment was significantly higher for turfgrass cover percent ratings only at the end of the 70-day window for both years. Fertilization, the more dominant factor, was applied at the start of the experiment (1 June) whereas mowing was not begun until four to five weeks later. Resin coated urea at 147 kg of N per ha, with a 6% Reactive Layer Coating, was most effective in providing the strongest and most uniform surface throughout the study according to playing surface measurement.

Introduction

The need for best management practices or strategies for re-establishing sports fields, after the playing season has finished, is a necessity for sports field managers. The 70-day summer window is ideal for sports fields to actively grow and repair itself. However, any cultural practices during this time get increasingly complicated when school and park crews leave for vacation or inclement weather occurs during summer. The need for strategies that are less expensive and time-consuming is evident.

A 2002 Michigan Rotational Survey (13) reported 13,500 acres of sports fields at university, college, primary, and secondary facilities. According to the survey, two practices sports turf managers performed most consistently, regardless of maintenance level, were mowing and fertilization.

Mowing is a common and essential practice for any turfgrass professional to implement. When mowing height decreases, there is an increase in shoot density, plants per unit area, and a decrease in rooting (1,5,8). Rogers and Waddington (17) reported differences on playing surface characteristics (surface hardness and traction) values on different mowing heights and verdure on an established tall fescue stand. However, they did not investigate the role of nitrogen fertility in this study. Lundberg (16) observed mowing twice per week at a consistent 5.0-cm mowing height increased plant counts compared to once per week. Sorochan et al. (18) evaluated different mowing heights for supina bluegrass (Poa supina Schrad.) under simulated traffic situations.

Fertilization is paramount for proper turfgrass health and is relatively inexpensive compared to other cultural practices. Extensive research has been conducted on fertilizers and their effects on turfgrass (6,11,12).

More specifically, slow-release fertilizers can provide potential benefits for the sports field manager, including, longer turfgrass response, less nitrogen leaching, less surface run-off, less volatilization, and fewer applications for healthy turfgrass response compared to quick release fertilizers (fertilizers that release or dissolve once in contact with water). Typically with urea, multiple applications are needed to attain responses observed by using a single slow-release fertilizer over a long period of time. Canaway (3) used soluble fertilizers for four applications for his study; however, chlorotic turfgrass was observed when establishing a turfgrass stand on a sand-based root zone. IBDU was applied for the fifth and final application.

Hummel and Waddington (11) have investigated sulfur-coated urea (SCU) as a slow-release fertilizer. Although SCU performed excellent in their studies, different responses can be generated due to variations in the coating thickness, coating methods, number of applications, and timing of applications throughout the year (2). Sports field managers tend to use fertilizer products that are less expensive due to a restrictive budget. Typical products used would be urea or SCU. Little research has evaluated these products or others in a short re-establishment window nor the agronomic effects on the playing surface.

Resin-coated ureas (RCU) are another alternative for slow-release fertilizers in the turfgrass industry. Unlike SCU, release rate of nitrogen in RCUs is not dependent upon outside factors such as rainfall/irrigation, microbial activity, and pH. As the polymer expands, urea/water solution is slowly released via the expanded pores in the polymer (2). Hummel (12) found a single-spring application of RCU-100 (number based on 7-day dissolution rates), at 196 kg of N per ha provided superior color compared to split treatments throughout the year. Fry et al. (6) also noted various turfgrass responses of RCU in established turf due to on resin thickness.

Studies have been conducted in evaluating a combination of mowing and fertility practices (5,8). These studies found more shoots were produced with a lower mowing height in conjunction with a higher rate of nitrogen. However, research did not focus on sports field management situations when time for preparation was a factor nor did the studies evaluate playing surface characteristics.

Limited research exists that investigates best management practices in re-establishing sports fields during a restricted time window while also evaluating the playing surface characteristics (surface hardness, traction, and divoting resistance) after traffic has resulted. The playing surface must function in terms of both aesthetics (turfgrass cover, plant counts, and color), and playing surface characteristics. Perennial ryegrass (Lolium perenne L.) established from seed and Kentucky bluegrass (Poa pratensis L.) sod were compared for sports fields before the playing season on a sand-based root zone (3,14). Sod produced a superior playing quality surface compared to seed when evaluating playing surface characteristics. Cook et al. (4) evaluated turfgrass establishment using hydroseeding (a mixture of primarily water, seed, fertilizer, and mulch sprayed on the intended target area) and compared results to seed and sod on a sand-based root zone. However, simulated traffic on these studies was not initiated until 125, 365, and 140 days after re-establishment, respectively. These studies implement practices (sodding and hydroseeding) that can be expensive and labor intensive from year to year.

The objectives were to (i) clarify the impact of best management practices in regards to mowing height and fertilization on re-establishment of sports field turf during a 70-day window, and (ii) quantify these effects during and after a 25-day simulated traffic period.

Measuring Effect of Mowing and Fertilization During and After Re-establishment Window

This study was conducted in 2002 and 2003 at the Hancock Turfgrass Research Center (HTRC) on the campus of Michigan State University in East Lansing, MI. The experiment was a randomized complete block design (RCBD) with two-factors and three replications. Three mowing heights and six fertilizer treatments were evaluated (Table 1) and re-randomized, in 2003, to avoid any edge effects from the first year. Plot size was 1.8 × 2.7 m. In 2002, sod cutters were used to strip out the existing sod, and in 2003, a Koro Field Topmaker (Pols International BV, The Netherlands) was used to strip the turf from the 2002 experiment. The soil was a sand-based profile (0.7%, 3.40 to 2.00 mm; 7.0%, 2.00 to 1.00 mm; 35.8%, 1.00 to 0.50 mm; 47.3%, 0.50 to 0.25 mm; 8.6%, 0.25 to 0.10 mm; 0.4 % 0.10 to 0.05 mm; 0.2% > 0.05 mm) and sterilized each year with Basamid G (Tetrahydro-3,5,-Dimethyl-2H-1,3,5, Thiadiazine-2 Thione) (Certis USA, Columbia,MD) at 392 kg/ha.

Table 1. Individual treatments for mowing and fertilizer study, 2002 and 2003.

Treatments		Total N used^y (kg/ha)
Mowing	3.8-cm-cont mowed at 3.8 cm throughout the study	—
	7.6-grad-3.8-cm^x maintained and mowed at 7.6 cm for 33 DAS and slowly dropped height to 3.8 cm - 3 July to 15 July, with 4 mowings at 7.6 cm - 16 July to 24 July, with 2 mowings at 6.3 cm - 25 July to 30 July, with 2 mowings at 5.1 cm - 31 July to 3 September, with 9 mowings at 3.8 cm	—
	7.6-chop-3.8-cm mowed at 7.6 cm and scalped to 3.8 cm 68 DAS	—
Fertilizer^z	Urea 49 kg of N per ha only on 1 July	98
	Urea 2w 16 kg of N per ha starting on 15 June every 15 days equaling 49 kg of N per ha	98
	SCU 147 kkg of N per ha	196
	RCU2 98 kg of N per ha	147
	RCU3 147 kg of N per ha	196
	RCUThin 196 kg of N per ha	245

^x In 2002, mowing started on 25 June and was mowed at 7.6 cm until 15 July. Six mowings occurred until 15 July.

^y Total N used includes starter fertilizer application (13-25-12) at 49 kg of N per ha plus treatments on 1 June.

^z Analysis of fertilizers:
- Urea 46-0-0, SCU 39-0-0, RCU2 and RCU3 43-0-0 and RCUThin 44-0-0.
- Seed and starter fertilizer (13-25-12) was applied on 1 June to all treatments.
- SCU, RCU2, RCU3, and RCUThin fertilizer treatments were only applied on 1 June.

Seeding and fertilizer treatments began on 1 June in both years. A 30:70 sports grass mixture (by weight) of perennial ryegrass (Lolium perenne L. var. SR4400, SR4500, and Manhattan III) and Kentucky bluegrass (Poa pratensis L. var. Champagne and Rugby II) was seeded at 196 kg/ha. Lebanon Country Club 13-25-12 (Lebanon Turf Products, Lebanon, PA) was applied at 49 kg of N per ha and subsequent fertilizer treatments were applied (Table 1). Fertilizer treatments applied were: Andersons urea (46-0-0) (Maumee, OH) at 49 kg of N per ha on 1 July (Urea) and 16 kg of N per ha every two weeks starting on 16 June, 1 July, and 18 July (Urea 2w); Lesco Poly-Plus sulfur-coated urea (39-0-0, 12% sulfur coating) (Strongsville, OH) at 147 kg of N per ha (SCU); and Polyon resin-coated urea (RCU) [43-0-0, 6% Reactive Layer Coating (RLC)] (Pursell Industries, Sylacauga, AL) at 98 kg of N per ha (RCU2), and 147 kg of N per ha (RCU3) and (44-0-0, 4% RLC) at 196 kg of N per ha (RCUThin). Germination blankets (model no. pr1715; A. M. Leonard, Piqua, OH) were placed over the top of the plot and removed 15 days after seeding (DAS) in both years. Based on visual quality throughout the experiment, potassium, phosphorous, and micronutrients were supplemented. Andersons 0-26-26 fertilizer and Andersons Trace Element Package (Maumee, OH) were applied at 49 kg P/ha and normal rate, respectively, on 27 June and 25 July in both years. Lebanon Country Club 18-3-18 (Lebanon Turf Products, Lebanon, PA) was broadcasted to all treatments at 24.5 kg of N per ha on 6 August and 19 August to supplement nutrients during traffic phases in 2002 and 2003. Irrigation was applied daily during re-establishment and as necessary throughout the experiment to prevent moisture stress.

Mowing began on 25 June 2002 and 3 July 2003, and treatments were mowed twice per week throughout the experiment (Table 1). During the re-establishment phase, the 3.8-cm-continuous strategy was mowed with a 43-cm-wide McLane mower (McLane Manufacturing Inc., Paramount, CA), and the 7.6-grad-3.8-cm (mowing height lowered weekly) and 7.6-chop-3.8-cm (Table 1) treatments were mowed with a Honda rotary mower (Harmony HRB216 Quadracut System, Honda Motor Company, Alpharetta, GA). The 7.6-chop-3.8-cm treatment was scalped down with an eXmark mower (Lazer Z HP, eXmark Corp., Beatrice, NE) to a height of 3.8 cm 68 DAS. From this point on, all mowing treatments were mowed at 3.8 cm height with the eXmark mower for the duration of the experiment. Clippings were returned at all times.

A traffic regime was applied on 12 August to 4 September in 2002 and 11 August to 3 September in 2003. Traffic was applied by the Cady Traffic Simulator (CTS) uniformly to all plots. The CTS was a modified Jacobsen Aero King 30 (A Textron Company, Charlotte, NC) self-propelled core cultivation machine with "rubber feet" and weighed 680 kg (10).

Data were collected during re-establishment and traffic phases. Turfgrass cover percent ratings, shear resistance, divoting resistance, peak deceleration, chlorophyll index, root pulls, and plant count values were measured. Once traffic began, data were collected in traffic lanes except in non-traffic lanes on 4 September 2002 and 3 September 2003.

Turfgrass cover percent ratings were estimated qualitatively. Data were collected on 2 July and 5 August 2002 (non-traffic), and 7 July, 4 August (non-traffic), 12 August, 19 August and 3 September (traffic lanes) 2003.

Traction values were measured by both the Eijkelkamp shear vane Type 1B (Giesbeck, The Netherlands) for shearing resistance and Clegg Turf Shear Tester (TST) (Wembley DC, Western Australia) for divoting resistance with a plate depth of 40 mm. Three measurements were recorded for each device and were measured in Nm. Data were collected for the Eijkelkamp shearvane on 15 August and 4 Sep 2002 (non-traffic and traffic lanes respectively), and 7 August (non-traffic), 13 August, 21 August, 28 August, and 3 September (traffic lanes) 2003. Data were collected for the TST in traffic and non-traffic lanes on 3 September 2003.

The Clegg Impact Soil Tester (CIT) (Lafayette Instrument Co., Lafayette, IN) was used to measure peak deceleration (G_max) values. A 2.25-kg hammer was dropped in three random locations per plot from a height of 0.46 m (17). Data were collected on 7 August (non-traffic), 13 August, 21 August, 28 August (traffic lanes), and 3 September (traffic and non-traffic lanes) 2003.

Data were analyzed using the Agricultural Research Manager (ARM) program (9). For each date, RCBD two-factor analysis was implemented in attaining an analysis of variance. Treatment means were separated using Fisher’s Protected LSD values at the 0.05 level.

Turfgrass Cover Percent

Mowing height only detected differences at the end of the 70-day trial, 5 August 2002 and 4 August 2003 for turfgrass cover percent (Table 2). These dates represented the last turfgrass cover percent ratings observed before simulated traffic was initiated. There were differences among fertilizers for every date regardless of traffic and non-traffic areas in both years. RCU3 was in the highest statistical category for every measuring date.

Table 2. Effects of mowing height and fertilization treatments on turfgrass cover percent (%) on a non-trafficked and trafficked perennial ryegrass/Kentucky bluegrass stand at the Hancock Turfgrass Reseach Center, East Lansing, MI, 2003.

Treatments		Turfgrass cover percent (%)
		2002		2003
		Non-traffic				Traffic
		2 Jul	5 Aug	7 Jul	4 Aug	12 Aug	19 Aug	3 Sep
Mowing^y	cont-3.8-cm	77	84	52	77	66	49	40
	7.6-grad-3.8-cm	72	85	57	81	69	51	41
	7.6-chop-3.8-cm	73	80	54	73	67	46	37
	LSD (0.05)	ns^x	4	ns	6	ns	ns	ns
Fertilizers^z	Urea	62	82	42	76	66	39	27
	Urea 2w	72	82	43	74	60	42	34
	SCU	69	78	47	68	61	43	32
	RCU2	83	86	69	81	74	62	49
	RCU3	88	92	76	92	84	68	66
	RCUThin	70	79	49	69	61	38	28
	LSD (0.05)	6	5	9	8	9	11	11
	No. of passes	0	0	0	0	8	16	34

^x ns = non-significance at the 0.05 level.

^y 3.8-cm-cont = 3.8 cm continuous; 7.6-grad-3.8 = 7.6 to 3.8-cm gradual mowing height; 7.6-chop-3.8 = 7.6 to 3.8-cm chop mowing height.

^z All fertilizer strategies received 49 kg of N per ha of 13-25-12 on 1 June. Urea, urea applied on 1 July at 49 kg of N per ha; Urea 2w, 16 kg of N per ha urea applied every two weeks; SCU, 147 kg of N per ha sulfur-coated urea; RCU2, 98 kg of N per ha resin-coated urea applied on 1 June; RCU3, 147 kg of N per ha resin-coated urea applied on 1 June; RCUThin has a thinner coating compared to other resin-coated ureas and 196 kg of N per ha resin-coated urea applied on 1 June.

SCU and RCU3 had the second highest amount of nitrogen, but these two products responded differently (Figs. 1 and 2). SCU releases nitrogen once water comes in contact with the urea prill via cracks and imperfections in the sulfur coating. RCUs combine irrigation/rainfall and high temperature (> 26°C) to slowly release nitrogen. The process is initiated when the RCU prill uptakes water, expands with heat and then slowly releases nitrogen via expanded pores in the coating at a steady rate (2). Consequently, due to a more controlled release from the RCU3, it rated higher in turfgrass cover percent (and others). Even RCU2, with 49 kg of N per ha less, and SCU, had differences between them. Even though RCUThin had the highest nitrogen rate, coating thickness was too thin to control the release of nitrogen and was possibly not available for the plants. Fry et al. (6) also noted various responses of RCU in established turf due to resin thickness. Consequently, the RCUThin fertilizer responded similarly to Urea, Urea 2w and SCU fertilizer strategies. The latter fertilizer strategies have been common practices for establishment of turfgrass stands which supports reasoning for evaluating these fertilizer strategies in this experiment. The rate of fertilizer and rate of release are important factors for sports field managers to consider when re-establishing turfgrass stands, especially when limited by a short time window of time and when utilizing a sand-based root zone. Even though time was minimal for re-establishment, the strategy is to get as close to 100% turf stand as possible. Larsen et al. (15) made conclusions from F values, and found the highest F values were associated with ground cover before the start of a playing season.

	A		B
	Fig. 1. On 28 July 2003, SCU (A) and RCU3 (B) both mowed at the 7.6-grad-3.8-cm mowing height before traffic.

	A		B
	Fig. 2. On 28 July 2003, SCU (A) and RCU3 (B) both mowed at the 7.6-chop-3.8-cm mowing height before traffic.

Mowing treatments (started on 25 June 2002 and 3 July 2003, respectively) had approximately a 35-day window compared to fertilizer treatments applied at the beginning of the 70-day re-establishment window. Even though more than one third of the plant was being removed from the 7.6-chop-3.8-cm treatment 68 DAS, differences were not observed among mowing treatments for turfgrass cover percent.

There were no significant differences among Urea, Urea 2w, SCU, and RCUThin for 5 of 7 measurement dates for both years combined. RCU3 was 14% and 18% higher compared to SCU on 5 Aug 2002 and 4 Aug 2003, respectively, before traffic commenced. Turfgrass cover percent loss after traffic revealed a 53% loss with SCU, but only a 28% loss with RCU3 between 4 Aug and 3 September 2003. Hummel and Waddington (11) observed N release characteristics for SCU being curvilinear with the most rapid response in the first two weeks following application. RCUs, on the other hand, have a minimal response following application, but then they released curvilinearly over a 200-day period at 25°C (7). Soil temperatures in the month of June, for 2002, averaged from 25 to 28°C from 1200 to 1800 h. In June 2003, average soil temperatures ranged from 19 to 25°C from 1200 to 1800 h. This might explain why turfgrass percent cover was higher in 2002 compared to 2003.

It should be noted turfgrass cover percentages did not reach 100% possibly due to germination blankets, seed mixture, and seeding rate. Germination blankets improved the response of the seedlings to germinate (compared to areas outside the experiment that did not get covered). However, due to excessive rain, wind, or removal of the blankets, some seed was displaced or adhered to the blanket during germination and were therefore removed when the blanket was removed. Proper seed spacing, uniformity, and surface development were not achieved with some treatments due to seed moving underneath the blankets and/or the dominance of perennial ryegrass (a bunch-type grass) germinating and establishing more quickly than Kentucky bluegrass. Canaway (3) suggested when using perennial ryegrass on a sand-based root zone, one option may be to double the rate. Therefore, a seeding rate of 392 kg/ha, instead of 196 kg/ha, might have improved turfgrass cover percent even though a 30:70 (perennial ryegrass : Kentucky bluegrass) sports field mixture was used.

Shear Resistance and Turf Shear Tester (TST)

Shear resistance and TST values are quantitative measures that clearly ascertained differences in strength of the surface after the 70-day re-establishment window, and during and at the end of the 25-day traffic regime (Table 3). RCU2 and RCU3 had shear resistant losses of 31% and 35%, respectively, from 7 Aug to 3 September 2003. Conversely, Urea, Urea 2w, SCU, and RCUThin had shear resistant losses of 61%, 50%, 48%, and 64%, respectively, on 3 September 2003. RCU3 had the highest shear resistance (an indication of strength of plants) and highest divoting resistance (an indication of rooting) on 3 September 2003. It also had differences in higher shear resistance values compared to SCU. Shear vane values were slightly lower than values recorded by Krick (14) for seeded perennial ryegrass, but establishment days were longer for their experiment. At the end of the 25-day traffic regime in 2003, only RCU2 and RCU3 had shear vane values above 10 Nm. On Kentucky bluegrass and supina bluegrass (Poa supina Schrad.) grown under low irradiance, Stier and Rogers (19) observed 10 Nm to be of minimal acceptance for sports fields. It should also be noted that RCU2 values were significantly higher than SCU and RCUThin for all dates except 3 September TST non-traffic values. RCU2 nitrogen amount was less than SCU and RCUThin (98 kg of N per ha compared to 147 kg of N per ha and 196 kg of N per ha without starter fertilizer, respectively). Type of coating and coating thickness were possible factors in releasing of nitrogen from the RCU2 fertilizer compared to SCU and RCUThin.

Table 3. Effects of mowing height and fertilization treatments on shear resistance and turf shear tester (TST) on a non-trafficked and trafficked perennial ryegrass/Kentucky bluegrass stand at the Hancock Turfgrass Research Center, East Lansing, MI, 2003.

Treatments		2002		2003
		Shear resistance (Nm)							TST (Nm)
		Non- traffic	Traffic	Non- traffic	Traffic				Traffic	Non- traffic
		15 Aug	4 Sep	7 Aug	13 Aug	21 Aug	28 Aug	3 Sep	3 Sep	3 Sep
Mowing^y	cont-3.8-cm	16	11	14	15	12	10	8	49	113
	7.6-grad-3.8-cm	16	11	15	15	12	11	8	53	108
	7.6-chop-3.8-cm	15	11	14	14	12	9	7	51	106
	LSD (0.05)	ns^x	ns	ns	ns	ns	ns	ns	ns	ns
Fertility^z	Urea	16	11	13	13	11	9	5	39	97
	Urea 2w	16	10	15	14	11	10	7	47	109
	SCU	15	10	13	14	11	7	7	48	112
	RCU2	18	12	16	17	14	13	11	61	112
	RCU3	17	12	18	17	15	13	12	70	118
	RCUThin	14	11	12	12	11	8	4	39	106
	LSD (0.05)	2	1	2	2	2	3	3	11	NS
	No. of passes	8	30	0	6	18	26	34	34	0

^x ns = non-significance at the 0.05 level.

^y 3.8-cm-cont = 3.8 cm continuous; 7.6-grad-3.8 = 7.6 to 3.8-cm gradual mowing height; 7.6-chop-3.8 = 7.6 to 3.8-cm chop mowing height.

Results presented may be due to a more accelerated wear compared to other data in the literature using different traffic simulators (2,3,4,14). The CTS is a more aggressive machine compared to traditional wear machines to date. Henderson et al. (10) provides an excellent review of simulated traffic machines. The CTS displays an up-and-down motion similar to an athlete running across the playing surface. It was found this action was more forceful compared to the Brinkman Traffic Simulator (commonly used for the sports turfgrass research at Michigan State University) which rolls across the playing surface (10).

Peak Deceleration

Peak deceleration values were relatively low in 2003 (Table 4). However, there was a consistent trend developing throughout the traffic regime in 2003. Treatments with lower G_max values (Urea, Urea 2w, SCU, and RCUThin) had more sand exposed at the surface and less turfgrass cover. Treatments with higher G_max values had less sand and more turfgrass cover exposed at the surface when using fertilizer treatments, such as RCU2 and RCU3 (an indication of strength of surface acting together). Rogers and Waddington (17), on a silt loam, found surface hardness increased as turfgrass cover decreased. They only detected differences with a 0.5-kg hammer compared to the 2.25-kg and 4.5-kg hammers when verdure was present on a tall fescue stand. Mowing height differences were trivial even though these heights were consistently maintained. Contrary to past research results, the CIT, with the 2.25-kg hammer, was sensitive enough to detect differences and provided quantitative information on playing surface characteristics in particular the uniformity and strength of the playing surface on a sand-based root zone.

Table 4. Effects of mowing height and fertilizer treatments on peak deceleration on a non-trafficked and trafficked perennial ryegrass/Kentucky bluegrass stand at the Hancock Turfgrass Research Center, East Lansing, MI, 2003.

Treatments		Non- traffic	Traffic				Non- traffic
		7 Aug	13 Aug	21 Aug	28 Aug	3 Sep	3 Sep
		G_max
Mowing^y	cont-3.8-cm	63	40	40	47	42	65
	7.6-grad-3.8-cm	60	39	40	46	43	65
	7.6-chop-3.8-cm	58	42	40	48	42	66
	LSD (0.05)	2	ns^x	ns	ns	ns	ns
Fertility^z	Urea	60	39	38	45	42	66
	Urea 2w	63	39	38	46	40	66
	SCU	59	40	41	46	42	65
	RCU2	59	45	41	47	44	63
	RCU3	60	42	41	50	47	64
	RCUThin	62	37	41	47	41	68
	LSD (0.05)	ns	4	3	3	4	NS
	No. of passes	0	6	18	26	34	0

^x ns = non-significance at the 0.05 level.

^y 3.8-cm-cont = 3.8 cm continuous; 7.6-grad-3.8 = 7.6 to 3.8-cm gradual mowing height; 7.6-chop-3.8 = 7.6 to 3.8-cm chop mowing height.

Gradually reducing the mowing height from 7.6 to 3.8 cm and using a RCU3 (at 6% RLC and 147 kg of N per ha) on a sand-based root zone produced the best management strategy. Specifically on 3 September 2003 for RCU3, it produced the strongest playing surface when considering the measuring parameters in this study [chlorophyll index readings, root pulls, and plants counts were also measured and produced similar results (unpublished data, due to word limits)]. SCU was erratic throughout the course of the experiment. Similarly, there was less of a turfgrass response when fertilizing with RCUThin, urea and Urea 2w compared to other RCU treatments RCU2 and RCU3. Coating of the urea prill and release rate were instrumental in this study.

The fertilizer strategy was more important than the mowing strategy for a 70-day window in the summer. First, there may not have been a wide enough difference among mowing strategies. Second, the fertilizer strategy was implemented for the full 70-day window while the mowing strategy was not implemented until halfway into the experiment because young seedlings were too immature to mow. An effective fertilizer strategy (product and rate) is paramount in a re-establishment growing window.

Implementing a mowing and fertilizer strategy, a sports field manager could reduce labor costs, and/or redirect labor to other projects, while also producing a better quality and safer surface for the upcoming playing season.

Acknowledgments

The authors would like to recognize Project GREEEN and Michigan Turfgrass Foundation for their generous support of this project.

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