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DATE DUE DATE DUE DATE DUE 5/08 K:IProj/Acc&Pres/ClRC/DateDue.indd QUANTIFICATION OF THE EFFECTS OF CULTURAL PRACTICES ON TURFGRASS WEAR TOLERANCE ON SAND BASED AND NATIVE SOIL ATHLETIC FIELDS By Lisa Marie Lundberg A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Crop and Soil Sciences 2002 ABSTRACT Quantification of the Effects of Cultural Practices on Turfgrass Wear Tolerance on Sand Based and Native Soil Athletic Fields By Lisa Marie Lundberg Methods of quantifying the effect of cultural practices on turfgrass wear tolerance on an athletic field were investigated on both a sand based field and a loam soil field. The variables manipulated in the research included fertilizing, mowing, and cultivation. Mowing rates consisted of mowing once or twice per week. Fertilization rates consisted of 25 g N at 5 g N m’zlapp., 25 g N at 2.5 g N m'z/ app., or 35 g N at 5 g N m'2/app. Cultivation rates consisted of no cultivation or cultivating twice per year. Each treatment was evaluated for color, quality, quantitative and qualitative density, shear strength, and surface hardness. Results for the sand soil study showed mowing twice per week increases turfgrass cover, quality, color, shear strength and decreases surface hardness. Fertilizing at the 25 g N m’2 year‘1 rate is good on a sand based root zone (at least 8 applications per year). Also, if less frequent fertilizer applications are used, a greater amount of annual nitrogen should be applied. Cultivation increased turfgrass cover and lowered surface hardness and shear strength. Results for the native soil study showed little variability. Due to drought, the turf was in summer dormancy throughout much of the experiment, thus potentially inhibiting the effect of the treatments. Copyright by Lisa Marie Lundberg 2002 Dedicated to John C. Sorochan, my parents, David and Lynn Lundberg and my sister, Andrea Scott Thank you TABLE OF CONTENTS Rage List of Tables .................................................................................................... vii List of Figures ................................................................................................... xii Introduction ....................................................................................................... 1 Chapter One: Impact of Cultural Practices and Traffic on a Sand Based Athletic Field ............................................................................... 5 Introduction .............................................................................................. 5 Materials and Methods ............................................................................ 9 Results and Discussion Brinkman .............................................................................. 17 Cady ................................................................................... 45 Conclusions ............................................................................. 68 Chapter Two: Impact of Cultural Practices and Traffic on a Native Soil Athletic Field ............................................................................... 70 Introduction ........................................................................................... 70 Materials and Methods ......................................................................... 74 Results and Discussion ......................................................................... 79 Conclusions ......................................................................................... 100 Appendices Appendix A ............................................................................ 103 Appendix B ............................................................................ 105 Appendix C ............................................................................ 109 Appendix D ............................................................................ 113 Bibliography ................................................................................................... 1 16 vi LIST OF TABLES Table 1- Particle-size analysis of sand based root zone ......................... 10 Table 2- Treatment applications for the sandy soil athletic field study, 1999-2001 ........................................................................... 12 Table 3- Annual fertilizer schedule for sandy soil athletic field study, 1999-2001 ........................................................................... 12 Table 4- Significance of treatment effects and Brinkman traffic on plant counts (plants 100cm'2) on a Poa pratensis/Lolium perenne turf stand, 2001 .............................................................................. 18 Table 5- Significance of treatment effects and Brinkman traffic on turfgrass cover on a Poa pratensis/Lolium perenne turf stand, 1999-2000 .................................................................................... 20 Table 6- Significance of treatment effects and Brinkman traffic on turfgrass cover on a Poa pratensis/Lolium perenne turf stand, 2001 ........................................................................................... 20 Table 7- Significance of treatment effects and Brinkman traffic on surface hardness (Gmax) on a Poa pratensis/Lolium perenne turf stand,1999-2000 ...................................................................... 22 Table 8-Significance of treatment effects and Brinkman traffic on surface hardness (Gmax) On a Poa pratensis/Lolium perenne turf stand,2001 .............................................................................. 22 Table 9- Significance of treatment effects and Brinkman traffic on turfgrass Eijelkamp shear strength (Nm) on a Poa pratensis/Lolium perenne turf stand, 1 999-2000 ........................................................... 23 Table 10- Significance of treatment effects and Brinkman traffic on turfgrass Eijelkamp shear strength (Nm) on a Poa pratensis/Lolium perenne turf stand, 1 999-2000 ........................................................... 23 Table 11- Significance of treatment effects and Brinkman traffic on turfgrass CIegg/shear strength (Nm) on a Poa pratensis/Lolium perenne turf stand, 2001 .................................................................. 25 Table 12- Significance of treatment effects and Brinkman traffic on turfgrass quality on a Poa pratensis/Lolium perenne turf stand, 1999-2000 ................................................................................... 26 vii Table 13- Significance of treatment effects and Brinkman traffic on turfgrass quality on a Poa pratensis/Lolium perenne turf stand, 2001 ........................................................................................... 26 Table 14- Significance of treatment effects and Brinkman traffic on turfgrass color on a Poa pratensis/Lolium perenne turf stand, 1999-2000 .................................................................................... 28 Table 15- Significance of treatment effects and Brinkman traffic on turfgrass color on a Poa pratensis/Lolium perenne turf stand, 2001 ........................................................................................... 28 Table 16- Significance of the interaction of mowing frequency, fertilizing rate and frequency and Brinkman traffic on turfgrass Eijelkamp shear strength on a Poa pratensis/Lolium perenne turf stand, 2001 ............................................................................. 39 Table 17- Significance of the interaction of mowing, cultivating, and Brinkman traffic on turfgrass Eijelkamp and Clegg/shear shear strength, surface hardness, and quality on a Poa pratensis/Lolium perenne turf stand, 2000-01 ............................... 41 Table 18- Significance of the interaction of fertilizing, cultivating, and Brinkman traffic on turfgrass Eijelkamp and CIegg/shear shear strength on a Poa pratensis/Lolium perenne turf stand, 2001 ........................................................................................... 41 Table 19- Significance of the interaction of mowing, fertilizing, cultivating, and Brinkman traffic on turfgrass cover, Eijelkamp shear strength, quality, plant counts and surface hardness on a Poa pratensis/Lolium perenne turf stand, 2001 ................................. 43 Table 20- Significance of treatment effects and Cady traffic on plant counts on a Poa pratensis/Lolium perenne turf stand, 2001 .......................................................................................... 46 Table 21- Significance of treatment effects and Cady traffic on turfgrass cover on a Poa pratensis/Lo/ium perenne turf stand, 2001 .......................................................................................... 48 Table 22- Significance of treatment effects and Cady traffic on surface hardness on a Poa pratensis/Lolium perenne turf stand, 2001 .......................................................................................... 50 viii Table 23- Significance of treatment effects and Cady traffic on Eijelkamp shear strength on a Poa pratensis/Lolium perenne turf stand, 2001 ........................................................................... 50 Table 24- Significance of treatment effects and Cady traffic on Clegglshear strength on a Poa pratensis/Lolium perenne turf stand, 2001 ................................................................................. 52 Table 25- Significance of treatment effects and Cady traffic on turfgrass quality on a Poa pratensis/Lolium perenne turf stand, 2001 .......................................................................................... 52 Table 26- Significance of treatment effects and Cady traffic on turfgrass color on a Poa pratensis/Lolium perenne turf stand, 2001 .......................................................................................... 54 Table 27- Significance of the interaction of mowing, cultivating and Cady traffic on turfgrass color, quality, and plant counts on a Poa pratensis/Lolium perenne turf stand, 2001 ............................ 64 Table 28- Significance of the interaction of mowing, fertilizing, cultivating and Cady traffic on turfgrass cover, plant counts, surface hardness and Clegg/shear strength on a Poa pratensis/Lolium perenne turf stand, 2001 ......................................... 66 Table 29- Treatment applications for the native soil athletic field study, 2000, 2001 .................................................................. 75 Table 30- Annual fertilizer schedule for native soil athletic field study, 2000-2001 ......................................................................... 77 Table 31- Significance of treatment effects and traffic on plant counts (plants 1OOcm'2), 2000-01 .................................................... 80 Table 32- Significance of treatment effects and traffic on turfgrass cover, 2000-01 ............................................................................ 82 Table 33- Significance of treatment effects and traffic on surface hardness, 2000-01 ........................................................................ 84 Table 34- Significance of treatment effects and traffic on turfgrass Eijelkamp shear strength, 2000-01 ................................................... 84 Table 35- Significance of treatment effects and traffic on turfgrass Clegg/shear strength, 2001 ............................................................. 85 Table 36- Significance of treatment effects and traffic on turfgrass quality, 2000-01 ............................................................................ 85 Table 37- Significance of treatment effects and traffic on turfgrass color, 2000—01 .............................................................................. 88 Table 38- Significance of the interaction of mowing frequency, fertilizing rate and frequency and traffic on turfgrass cover, plant counts, and Eijelkamp and Clegg/shear shear strength, 2001 ................ 96 Table 39- Significance of the interaction of fertilizing, cultivating and traffic on turfgrass quality, cover, Eijelkamp shear strength, and surface hardness, 2001 ....................................... 97 Table 40- Significance of the interaction of mowing, fertilizing, cultivating and traffic on turfgrass quality, cover and plant counts, 2001 ......................................................................................... 99 Table 41- Michigan High School Survey .......................................... 103 Table 42- Results for Football Game fields from the survey sent to Michigan High Schools, 1999-2000 ............................................. 104 Table 43-Temperature and Rainfall for Hancock Turfgrass Center 2000-01 .................................................................................... 105 Table 44a and b-Cost Analysis for Treatments Sand Soil ......................................................................... 109 Native Soil ....................................................................... 110 Table 45a-d-Percent cover and plant count comparisons between treatments for the Brinkman and Cady traffic simulators ..................... 111 LIST OF FIGURES Figure 1- Brinkman Traffic Simulator ................................................. 14 Figure 2- Cady Traffic Simulator .................................................... 14 Figure 3- Effect of fertilizing and Brinkman Traffic on turfgrass cover over time, 2000 ................................................................... 44 Figure 4- Effect of fertilizing and Brinkman Traffic on turfgrass cover over time, 2001 ................................................................... 44 Figure 5- Effect of mowing and Brinkman Traffic on turfgrass cover over time, 2001 ................................................................... 44 Figure 6- Effect of mowing and Cady Traffic on turfgrass cover over time, 2001 ................................................................... 67 Figure 7- Effect of fertilizing and Cady Traffic on turfgrass cover over time, 2001 ................................................................... 67 Figure 8. Comparison of Turf Density between treatments under Brinkman Traffic, 2001 ....................................................... 113 Figure 9. Comparison of Turf Density between treatments under Cady Traffic, 2001 ............................................................. 113 Figure 10. Turf Density as Effected by Fertilizer and Brinkman Traffic (Mown 1x/week),2001 ........................................... 113 Figure 11. Turf Density as Effected by Fertilizer and Brinkman Traffic (Mown 2x/week),2001 ........................................... 113 Figure 12. Turf Density as Effected by Fertilizer and Cady Traffic (Mown 1x/week) ............................................................... 114 Figure 13. Turf Density as Effected by Fertilizer and Cady Traffic (Mown 2x/week) ............................................................... 114 xi INTRODUCTION An athletic field is made up of many components and the interaction between these components determines the playability of the field. These components can be divided into two levels; components that have a direct effect on game play (level one) and components that have an indirect effect on game play (level two). Level one factors include field stability, ball roll, rebound resilience, and traction (Canaway etal., 1990). Level two factors include turfgrass cover, surface hardness and uniformity, and drainage (Adams, 1981; Canaway, 1984; Holmes and Bell, 1986; Rogers et al., 1988; McClements and Baker, 1994). The two attributes most frequently cited in relation to field playability, and subsequently field safety, are turfgrass cover and surface hardness (Harper et al., 1984, Rogers et al., 1988). Although these two attributes, and to a lesser extent traction and player performance (Waddington and McNitt, 1995), are the most commonly sited in relation to player injury, all of the aforementioned factors affect the safety and the longevity of the field. If one or all of these factors are not at an adequate level, then player injury can potentially result. In 1965 athletic injuries were correlated with poor field conditions (Wilcox etal., 1965). Sanderson (1979) suggested that soil compaction is the major cause of these injuries. Orchard et al. (1999) suggested that water, or the lack of water on the field’s surface has a specific effect on knee injury occurrence. These findings support the idea that poor surface conditions lead to increased athletic injury. This idea was quantified in 1981 when a study was done at twelve different Pennsylvania high schools (24 fields). This study found an accumulative average of 210 football injures occurred during the football season. Of these injuries, 21% were rated as definitely or possibly related to field conditions (Harper et al., 1984). This study also highlighted the fact that generally, the better maintained a field, (adequate nitrogen supply, frequency of cultivation, and frequency of mowing), the better the playing conditions (increased field uniformity, greater cover, and fewer weeds). With the increase of participation in sports in Michigan, athletic field managers are being pressured to maintain fields adequately so the potential of field related injuries can be reduced. Unfortunately, many of the field managers do not have adequate knowledge of field maintenance. To measure the extent of this knowledge, a survey was sent through the Michigan High School Athletic Association to high schools in December 1999 and 2000. The results of this survey are displayed in Appendix A. Generally, the survey revealed there is a need for general guidelines for athletic field maintenance as well as a need for the quantification of the effect of the maintenance practices on athletic fields. In response to these concerns, a study was initiated at Michigan State University to evaluate a range of management programs considered typical for Michigan athletic fields. Each of these programs was evaluated with respect to its effects on field longevity. The hypothesis was if the maintenance practices were implemented at the proper rate and frequency, increased turfgrass density and field stability, and decreased surface hardness would result. An additional goal of this study was to analyze the cost benefit of each regime. This analysis will help athletic directors who often have difficulty developing, justifying, and attaining an annual maintenance budget. The 12 treatments of this study consisted of three levels of fertilization, low infrequent (25 g N at 5 g N m’2/app.), low frequent (25 g N at 2.5 g N m'2/app.) and high (35 g N at 5 g N m'zlapp.), two frequencies of cultivation (zero (low) and twice (high) per year), and two frequencies of mowing (once (low) or twice (high) per week). These three variables represent the major cultural practices over which athletic field managers have control. The study was conducted on two different root zones, one was a sand soil base, and the other was a Capac loam soil (Fine-loamy, mixed, mesic Aeric Ochradqualfs). The study was conducted on these two root zones because both have benefits for athletic field traffic and may respond differently to treatments. With this study, we intend to learn what the incremental returns of field quality are as compared to the inputs of maintenance practices. Previous research has found that mowing, fertilizing, and cultivating, done at the proper rates and frequencies, can increase turfgrass cover, decrease surface hardness, and improve surface conditions that affect player injury (Adams, 1981; Canaway, 1984; Harper et al., 1984; Holmes and Bell, 1986; Rogers et al.,1988; McClements and Baker, 1994; Waddington and McNitt, 1995). However, research has yet to answer how this information relates to a game field. Thus, it needs to be determined how long the effects of these practices will last under athletic traffic. There is an abundance of research supporting the guiding principals set forth in this thesis; however, none of the research thus far can answer the question of how many more games an athletic field can hold by following these principals. This research is the pioneer for what should be continued research in the quantification of the effects of management practices on athletic field life expectancy. Specific Objectives 1. Quantify the relationship between 12 turfgrass management programs and turfgrass longevity under trafficked conditions on a sand based root zone athletic field. 2. Quantify the relationship between 12 turfgrass management programs and turfgrass longevity under trafficked conditions on a native soil athletic field soil. Chapter 1 Impact of Cultural Practices and Traffic on a Sand Based Athletic Field Introduction The combination of grass, maintenance, and condition of the root zone are essential components in determining if an athletic field will hold-up under game traffic, or if it will fail. The grass provides the cover of the field as well as added stability. If a field is used beyond its capacity, worn areas will occur, resulting in a lack of stability and decreased playing surface conditions. Worn areas and instability have been shown not only to reduce the playability and aesthetics of the field but also to increase field-related injuries (Harper et al., 1984; Rogers et al., 1988). The root zone is the source of nutrient and water for turfgrass growth and it provides for the stability of the grass plants by anchoring their roots (Beard, 1973) An athletic field must provide firm footing, adequate resiliency on impact, and resistance to tearing during play. It must also drain well and resist compacting effects of severe traffic (Turgeon, 1996). This statement describes a combination of the two most commonly used athletic field root zones today. It describes the resistance to compaction of a sand based root zone and it describes the firm surface of an “existing” or native soil root zone-which is higher in silt + clay then a sand based field. Because both of these root zones have benefits for athletic traffic and may respond differently to treatments, this research was done on both types of root zones. The benefits of using a sand based root zone for athletic field construction are that the macropore space provides for increased water, nutrient, and air movement, rapid drainage, and resistance to compaction (Bingaman and Kohnke, 1970; Brown and Duble, 1975; Adams, 1976; Blake, 1980). This allows for play in adverse conditions as well as potential for increased rooting and shoot growth. Unfortunately, sand based fields have less desirable characteristics as well. Not only can they be more expensive then a native soil field, but they can be unstable and the large macropore space provides for little plant available water holding capacity. Also, low clay and organic matter content provide little cation exchange capacity (Carrow et al., 2001). As result, sand based root zones need to rely heavily on plant root systems for support (Adams and Jones 1979; Adams et al., 1985). Therefore, choosing the proper grass species is very important, especially on a sand based athletic field. A grass with strong rooting and recuperative capabilities is essential. For these reasons a Kentucky bluegrass/perennial ryegrass mixture was used for this research. Kentucky bluegrass provided the dense system of rhizomes which anchor it to the root zone, thereby giving the field good recuperative potential. Perennial ryegrass provided rapid germination, high wear tolerance, and deep rooting (Beard, 1973). The maintenance practices for this research consisted of twelve different treatments, compromised of three treatment factors each; mowing, fertility, and cultivation. Plots were mown either once or twice per week for the low and high treatment, respectively. These rates were chosen because they correlate with what is done on the majority of high school athletic fields in Michigan (Appendix A). In addition, the high mowing frequency stays within the one-third rule- especially during the summer and early fall months-while the low mowing frequency does not. The one-third rule was based upon findings by Crider (1955). The one third rule defines that no more then one third of the plant should be removed at any one mowing: otherwise, imbalance between shoots and roots may impede growth (Turgeon, 1996). By using two different mowing frequencies, we can demonstrate the potential benefits of proper mowing practices. The mowing height used was one inch lower then the average mowing height in Michigan (Appendix A); however, we chose it because it is within the preferred range for both Poa pratensis and Lolium perenne and because sand based fields are usually associated with highly maintained, irrigated fields, therefore, they can tolerate a lower mowing height. The fertilizer was applied in accordance with the rates commonly used on Michigan athletic fields (Appendix A). A variety of these rates were used to determine if the rate of growth and development of the grass would differ at different rates when subjected to traffic. In addition, we investigated varying application frequencies within the low rate of nitrogen. This was investigated to determine if more frequent applications of nitrogen could potentially help compensate for the low nutrient holding capacity of the sand root zone. Plots were cultivated with a hollow tine core aerifier at the end of each traffic season and in the spring when turfgrass growth and development is high; or plots were not cultivated at all. The frequencies of cultivation were chosen to represent what is commonly done on Michigan athletic fields (Appendix A). Although a sand root zone field is not likely to compact, some of the reasons for coring were to disrupt the root zone surface area. This is important to prevent a potential layering problem from occurring from the decomposition of organic matter from roots and clippings. The decomposing organic matter could seal the pore space at the root zone surface and this could eventually cause a layering problem leading to anaerobic conditions (Carrow 2001). This would result in decreased rooting and subsequently, decreased stability and decreased turf health and vigor (Harper, 1991) All plots were subjected to simulated traffic using the Cady Traffic Simulator (CTS) or the Brinkman Traffic Simulator (BTS). The CTS was used in the second year because the wear from it is more representative of actual human traffic, it is much more intense then the traffic simulated by the BTS. The results of this study will be used to quantify the relationship between cultural practices and turfgrass quality on two commonly used athletic field root zone types. Materials and Methods Plot Construction Individual plots measured 2.7 m by 2.7 m. Beginning 20 May 1999, plots were established on a sand based root zone at the Hancock Turfgrass Research Center in East Lansing, Michigan (Table 1). Prior to seeding, the area had been treated with a starter fertilizer (13-25-12; 5 g phosphorus (P)/m'2) and Siduron, a preemergent herbicide (Kansas City, MO 50% Siduron and 50% Inert ingredients, wettable powder) for control of grassy weeds. Siduron was applied at a rate of 10 g rn'2 The only other maintenance procedure necessary was one spray application of Confront (Indianapolis, IN 33% triclopyr, 12.1% clopyralid, liquid formulation) on 8 May 2001 at a rate of 024 ml m'2 for control of broadleaf weeds. Seed was an 85% Kentucky bluegrass (Varieties: Touchdown, Fairfax, SR2100, and Midnight), 15% perennial ryegrass mixture (ASP410, Michigan State Seed Co., Grand Ledge, Ml). Kentucky bluegrass was used because it grows by rhizomes which give it good recuperative potential (Beard, 1973). Perennial ryegrass was used because it has good wear tolerance and rapid germination (Beard, 1973). Seed was broadcast at a rate of 20 g rn’2 and the area was fertilized weekly for 5 weeks using a Lebanon Country Club 13-25-12 fertilizer (Lebanon, PA) at a rate of 5 g P m‘z. The field was mown for the first time on 18 June 1999 to a height of 3.2 cm using a Tom GTSF lawn mower (Toro 00., Minneapolis, MN). Once the field had filled in, (five weeks after seeding) it was mown each Table 1. Particle-size analysis of sand root zone. Size class (mm) (um) mesh # % Retf % Passirfif Fine gravel 12700-2000 2000 10 0.4 99.6 Very coarse sand 2000-1.000 1000 18 7.2 92.4 Coarse sand 1000-0.500 500 35 31.7 60.7 Medium sand 0.5000250 250 60 44.2 16.5 Fine sand 0.2500100 106 140 10.4 6.1 Very fine sand 0100-0050 53 270 1.0 5.1 Silt 0050-0002 1.3 3.8 Clay < 0.002 3.8 0 T Indicates the percent by weight of soil particles remaining in each size class. 1 Indicates the percent by weight of soil particles passing through each sieve. 10 week using a zero turn rotary mower at a setting of 3.8 cm. In addition, Lebanon Country Club 18-3-18 fertilizer (Lebanon, PA) was applied weekly for the next 10 weeks at a rate of 5 g N m'z. Possibly due to the herbicide application, bare areas needed to be overseeded on 22 June, 12 July, and 11 August 1999. In 2000, the entire area was overseeded with the same seed mix on May 11 at a rate of 15 g m'z. Plot maintenance The experimental design for this study was a 2 x 3 x 2 (mowing x fertilizing x cultivating) randomized complete block design with three replications. The two levels of mowing consisted of mowing once per week (Low) or twice per week (High) at a height of 3.8 cm. The three levels of fertilizer consisted of 5 g N m'2 applied five times per year for a total of 25 g N m'2 yr" (Low Infrequent), 2.5 g N m‘2 applied 8 times per year for a total of 25 g of N m‘2 yr‘1 (Low Frequent), or 5 g N m'2 applied 7 times per year for a total of 35 g N m'2 yr'1 (High). The two levels of cultivating consisted of zero (Low) or two times per year (High). These treatments are outlined in Table 2. Mowing treatments began the first week of May 2000 and 2001. All plots were mown to a height of 3.8 cm using a Toro zero turn mower (Toro Co., Minneapolis, MN) once per week. Plots mown at the high level were mown an additional time each week with a reel mower set at 3.8 cm. Fertilizer treatments began for all plots receiving the low frequent fertility application on 26 October 1999. On 10 November 1999, a 10 g N m'2 of urea 11 Table 2. Treatment applications for the sandy soil athletic field study, 1999-2001. Treatment Mowing"r (times/week") Fertilizer" jg N m'ivear") Cultivation§ 1 1 25(LIF) NO 2 1 25(LIF) Yes 3 1 25(LF) No 4 1 25(LF) Yes 5 1 35(High) NO 6 1 35(High) Yes 7 2 25(LIF) No 8 2 25(LIF) Yes 9 2 25(LF) No 1 0 2 25(LF) Yes 11 2 35(High) No 1 2 2 35(High) Yes T The sandy soil study was mown at 3. 8 cm. 1 The fertilizer treatments consisted of low infrequent, low frequent, and high levels. UP: 25 g N m'2 year with 5 applications; LF= 25 g N rn'2 year with 8 applications; High: 35 g N m'2 year with 7 applications. § Cultivation consisted of spring and fall core cultivation. Table 3. Annual fertilizert schedule for sandy soil athletic field study, 1999- 2001. Year Date Low Infrequent Low Frequent High «mu-Lg N m'2 application" 1999 26 October 2.5 11 November’ 5.0 5.0 5.0 Total 9 N m'zlyr. 5.0 7.5 5.0 2000 01 May - 2.5 - 20 May 5.0 2.5 5.0 10 June -- 2.5 5.0 01 July 5.0 2.5 5.0 01 August -- 2.5 5.0 01 September 5.0 2.5 5.0 180ctober 5.0 5.0 5.0 18 November‘ 5.0 5.0 5.0 Total 9 N m'zlyr. 25 25 35 2001 03 May 2.5 22 May 5.0 2.5 5.0 12 June - 2.5 5.0 03 July 5.0 2.5 5.0 02 August -- 2.5 5.0 03 September 5.0 2.5 5.0 19 October 5.0 5.0 5.0 20 November‘ 5.0 5.0 5.0 Total N m“2 25 25 35 f Scotts® ProTurf fertilizer 18-5-18 1: Dormant fertilization using urea (46-0-0). 12 (46-0-0) dormant feeding was given to all plots. For the years 2000 and 2001, Scotts 18-5—18 fertilizer (Scotts, Marysville, OH) was applied 5, 7, or 8 times per year (Table 3). Fertilizer was applied with a drop spreader unless all plots were to receive at least 2.5 g of N m'z. In this case, a rotary spreader was used to apply the 2.5 g of N m'2 and a drop spreader was used to apply the additional 2.5 g of N m'z. Plots were cultivated on 9 May and 28 November 2000, and 9 May and 05 December 2001 using a 1.2 m Toro walking greens aerator (Toro 00., Minneapolis, MN) with 7.6 x 0.64 cm hollow tines. Traffic Simulation For traffic simulation, each 2.7 x 2.7 m plot was split in half. In 2000, one half of the plot received Brinkman traffic simulation and the other half received no traffic. In 2001, one half received Brinkman traffic simulation and one half received Cady traffic simulation. The same half received Brinkman traffic in 2000 and2001. E'l I [I] S' I | All treatments were subjected to simulated traffic using the Brinkman Traffic Simulator (BTS) in 2000 and 2001. The BTS imposes both compactive and minimal tearing forces on the turf by using full rollers with metal cleats. Two passes with the BTS equal the number of cleat marks made between the hash marks and between the 40 yard lines during one NFL football game (Cockerham 13 v . . . l I I 1mm“? "um: um 41 if .f. ' “’._‘l. I‘ ( Figure 2. Cady Traffic Simulator and Brinkman, 1990). For this research, two passes were made 2 times/week beginning on 24 August continuing through 16 November of 2000 and 27 August continuing through 19 November of 2001 for a total of 50 passes (25 games) each year. W All treatments were subjected to simulated traffic in 2001 using the Cady Traffic Simulator (CTS), which is a modified Jackobson core-aerifier that simulates traffic by imposing compactive and tearing forces on the turf. The CTS was recently built by Jack Cady for Michigan State University (Lansing, MI) because the wear from the BTS did not simulate actual human athletic traffic. The CTS uses recycled car tires with metal spikes to simulate the compactive and tearing forces being applied by a human foot (non-published data). The number of spike marks per square foot does not differ significantly from the BTS where two passes equal the cleat marks made between the hash marks of the 40 yard line during one National Football League game (Henderson, 2001, personal contact). Exact calibrations for the compaction and shearing effects of the CTS are currently undenlvay. Cady traffic simulation took place on the half of the plot that was not trafficked by the Brinkman. Trafficking began 27 August continuing through 19 November for a total of 24 games for the 2001 season. Data Collection 15 Turfgrass cover, color, quality, shear strength, and surface hardness ratings were made in September and October of 1999, and monthly from May * through November of 2000 and 2001 for treatments trafficked by the BTS. Data was collected August through November 2001 for treatments trafficked by the CTS. The turfgrass cover ratings were based on a visual percent cover scale (0- 100%). Beginning in 2001, density was also measured quantitatively by plant counts 1000m'2. Quality and color were rated on a visual (1-9) scale. For quality ratings, a rating of one was given for dead or no turf, six for acceptable turf, and nine for excellent turf. For color, a rating of one was given for yellow or brown turf, six for acceptable turf color, and nine for dark green. Beginning in July of 2001, color was assessed using the SpectrumTM FieldScout chlorophyll meter (Spectrum Technologies, Inc., Plainfield, IL). Shear strength was measured using an Eijelkamp shear vane (Eijkelkamp, Giesbeck, The Netherlands) and beginning in August of 2001, shear strength was also assessed using the Shear Clegg (Dr. Baden Clegg Pty Ltd., Perth, Australia). Both tools were used because they measure different aspects of shear strength. The Eijkelkamp shear vane measures rotational shear strength, thereby effecting the plants and plant tillers. The shear/Clegg measures lateral shear strength, thereby having more of an effect on plant displacement from the soil. Surface hardness was measured using a 2.5 kg Clegg Impact Hammer (Lafayette Instrument Co., Lafayette, IN). 16 Results and Discussion Brinkman Traffic Simulator All data was analyzed as a factorial, randomized complete block design using the Agriculture and Resource Management program. Results and discussion are presented by maintenance practice and then subdivided by the effect each practice had on the evaluation criteria. Interaction results and discussion are at the end of the chapter. Because of variability within data collection devices and because statistical significance can contrast with actual significance, we designated surface hardness and shear strength measurements between treatments to be inconclusive if differences were less then 5 gmax 5 Nm. Comparisons between treatments for plant count and percent cover ratings are listed in Appendix C. A cost analysis for each treatment is also listed in Appendix C. Mowing Plant counts Plots mown twice per week yielded 15-22 % higher plant counts then plots mown once per week beginning in July and continuing through November of 2001 (Table 4). The increase in plant counts for plots mown twice per week may have been because mowing, at the proper height and frequency stimulates shoot growth and tillering (Crider 1955; Juska, 1961). However, if more then 30% of the leaf blade of a plant is removed in a single mowing, then all, or nearly all, of 17 Table 4. Significance of treatment effects and Brinkman traffic on plant counts (plants 100cm 2I) on a Poa pratensis/Lolium perenne turf stand, East Lansing, MI. 2001 5/08 6/04 7/19 8/25 10l01 10/15 10/29 1 1/09 1 1/16 Mowing 1x/week 110.0 210.9 212.5 171.1 166.7 145.1 122.9 127.8 109.0 2x/week 116.2 226.6 238.4 201.6 213.9 172.9 144.0 152.3 143.1 Significance ns ns t it ii. it. fit it it. FertilizationI Low infrequent 105.1 201.0 213.5 178.5 182.3 149.7 126.7 133.3 111.5 Low frequent 127.4 239.9 230.6 191.0 186.8 160.1 133.0 148.3 121.2 High 106.8 215.3 232.3 189.6 201.7 167.4 140.6 138.5 145.5 _Significance ns * ns ns ns ns ns ns ** Cultivation 0x/yr"116.2 224.1 225.9 185.9 192.1 165.1 129.4 140.1 131.0 2x/yr'I110.0 213.4 225.0 186.8 188.4 153.0 137.5 140.1 121.1 Significance ns ns ns ns ns ns ns ns Ns # of Games - - - - 10 15 19 22 25 * ,** ,"* Significant at the 0.10, 0.05, and 0.01 probability levels, respectively. Ns Not significant at the 0.10 probability level. I Plants were hand counted using three subsamples per treatment. I Low infrequent fertilizer - 25 g N 111'2 year with 5 applications; Low frequent“ - 25 g N m'2 year Iwith 8 applications; High= 35 g N m‘2 year’ Iwith 7 applications. 18 the plants energy goes into shoot production and negligible amounts, if any go into root, rhizome, or tiller initiation (Crider, 1955). Thus, once traffic simulation began, the root systems of the plants mown once per week may not have been as strong as the root systems of the plants mown twice per week, because all of their energy was being put towards shoot development. Therefore, when put under stress, these plants were removed from the ground much more easily causing a decrease in plant counts. Between the rating dates of 01 and 15 October, there was a large drop in plant counts. This may have been because as traffic simulation continued, the optimal growth period for plant recovery was coming to an end. Turfgrass cover No differences were seen between mowing treatments in 2000. However, in 2001, mowing twice per week yielded a 2-12% increase in turfgrass cover ratings in every month except July and August (Tables 5 and 6). The year 2000 showed no differences in turfgrass cover with respect to mowing frequency. In 2001, plots mown twice per week had higher turfgrass cover ratings in May and again on 01 October through 16 November (although the June and September ratings are statistically significant, the June ratings of 90 and 92% and the September ratings of 96 and 98% for the low and high mow treatments respectively, were too close to accept statistical significance). From June through early August, plant growth was fairly slow because growing conditions were not optimal. As a result, differences between treatments were less obvious because less leaf tissue was being removed with each mowing, thus less stress 19 Table 5. Significance of treatment effects and Brinkman traffic on turfgrass coverI on a Poa pratensis/Lolium perenne turf stand, East Lansing, MI. 1999-2000. 1999— 2000 9/15 10/15 11l15 5/15 6/15 7/15 8/15 9/15 10/13 10/20 10/27 11/15 Mowing 1x/week 97 96 96 78 97 98 100 100 80 81 80 78 2x/week 96 95 96 77 96 99 100 100 82 80 82 80 flgnificance na na na ns ns ns ns ns ns ns ns ns F ertIlIzatIon Low infrequent 95 94 95 72 95 97 100 100 72 74 73 72 Low frequent 97 97 97 86 99 99 100 100 85 84 84 83 High 96 95 95 75 97 99 100 100 86 83 85 83 Iflgnificance ns ns ns it. it. it. ns ns iii it. it. fit Cultivation Oxlyr" 97 96 96 77 97 99 100 100 79 79 79 78 2x/yrI 96 95 96 78 96 98 1 00 1 00 82 81 82 80 Significance na na na ns ns ns ns ns ns ns ns ns # of Games - - - 7 15 17 19 25 * ,“ ,*“ Significant at the 0.10, 0. 05, and 0.01 probability levels, respectively. Ns Not significant at the 0.10 probability level. Na Not applicable, prior to treatment application. ITurf cover was visually estimated on a percent (0-100%) scale. I Low infrequent fertilizer- — 25 92 N m'2 ear Iwith 5 applications; Low frequent - 25 g N m'2 year Iwith 8 applications, High= 35 g N m2 year with 7 applications. Table 6. Significance of treatment effects and Brinkman traffic on turfgrass coverI on a Poa pratensis/Lolium perenne turf stand, East Lansing, MI. 2001. 5/15 6/15 7/15 8/25 9/12 10/01 10/15 10/26 11/09 11/16 Mowing 1x/week 63 90 98 100 96 77 78 66 48 35 2x/week 75 92 99 100 98 85 83 72 59 44 Significance it! i ns ns 9*. it. it it. it! it. FertilizationI Low infrequent 55 88 97 100 97 77 76 64 47 36 Low frequent 81 93 100 100 97 81 79 69 51 36 High 72 92 99 100 98 85 86 75 63 46 finiflcance it! it. it ns ns 9.. i". tit ii. iii Cultivation OxlyrI 67 91 99 100 97 80 80 67 52 37 2xlyrI 71 91 99 100 97 82 81 72 56 42 Significance ns ns ns ns ns ns ns “ “ **' # of Games - - - - 5 10 14 18 22 25 * ,,"" “" Significant at the 0.10, 0.05, and 0.01 probability levels, respectively. Ns Not significant at the 0. 10 probability level. ITurf cover was visually estimated on2 a percent (0-100%) scale. ILow infrequent fertilizer - 25 g N m2 year 1with 5 applications; Low frequent - 25 g N m2 year" with 8 applications, High= 35 g N m year Iwith 7 applications. 20 was put upon the plants. Therefore, mowing frequency effects on turfgrass cover really did not begin to show until turfgrass growth slowed and traffic simulation continued. At this time, plots mown twice per week had higher turfgrass cover ratings. These results mirror what was seen in plant count ratings. Thus, similar to plant counts, this effect most likely occurred as a result of a weakened root system. Surface hardness Statistical significance occurred for mowing once per week versus twice per weekin May (50.7, 48.6), August (54.2, 57.5), and November (57.7, 56.0) of 2000 and June (43.3, 44.6) of 2001 (Tables 7 and 8). However, because the actual difference between surface hardness ratings was so small (less then 5 Gmax), it is inconclusive as to whether or not mowing frequency had an effect on surface hardness characteristics. Rogers and Waddington (1990) also found that cutting height and biomass have little effect on surface hardness. Shearvane Statistical significance occurred for mowing once per week versus twice per week in August of 2000 (20.0, 21.4), and August (14.4, 14.8) and September of 2001 (18.7, 17.6) (Table 9 and 10). These results indicate there is an increase of shear strength following summer mowing. However, because the actual difference between shear strength ratings was so small, it is inconclusive as to whether or not mowing frequency had an effect on shear vane ratings. Previous research has shown that for treatment effects to be actually significant, the 21 Table 7. Significance of treatment effects and Brinkman traffic on surface hardness (Gm...)I on a Poe pratensis/Lolium perenne turf stand, East Lansing, MI. 1999-2000. —1999 2000 10/15 11/15 5/15 6/15 7/15 8/15 9/15 10/15 11/15 Mowing 1x/week 66.3 67.2 50.7 62.3 61.1 54.2 61.1 64.3 57.7 2x/week 65.3 63.3 48.6 63.7 61.4 57.5 61.7 62. 4 56.0 _Si_gnificance na na "’ ns ns ** ns ns ** FertilizationI Low infrequent 65.0 65.7 50.1 63.4 62.4 57.6 61.0 63. 7 57. 7 Low frequent 66.1 65.4 47.6 60.4 58.4 53.1 62. 3 64.8 56. 3 High 66.3 64.6 51.2 65.3 63.0 56.9 60. 7 61.7 56.4 flgnificance ns ns “* m "" *‘ ns ns ns Cultivation Oxlyr'I 65.7 64.2 50.0 67.3 63.4 57.8 62.9 65.3 57.6 2x/yrI 65.9 66.2 49.3 58.7 59.1 54.0 59.7 61.4 56.0 Significance na na ns “" ”* *‘ m * “ # of Games - - - - - - 7 15 25 *,“,*** Significant at the 0.10, 0.05, and 0.01 probability levels, respectively. Ns Not significant at the 0.10 probability level. Na Not applicable, prior to treatment application. I Surface hardness was measured using the Clegg Impact Soil Tester' In gravity deceleration Gmax) I Low infrequent fertilizer - 25 g N m2 year Iwith 5 applications; Low frequent- - 25 g N m2 yearI with 8 applications, High= 35 g N m year Iwith 7 applications. Table 8. Significance of treatment effects and Brinkman traffic on turfgrass surface hardness (Gm )I on 3 Pee pratensis/Lolium perenne turf stand, East Lansing, MI. 2001. 5/15 6/15 7/15 8/25 9/12 10/01 10/15 10/26 11/09 11/16 Mowing 1x/week 40.2 43.3 45.9 45.0 44.0 50.1 46.4 48.9 51.1 50.3 2x/week 40.4 44.6 45.9 45.7 43.4 49.3 47.4 49.7 50.8 50.3 Significance ns * ns ns ns ns ns ns ns ns FertilizationI Low Infrequent 40.9 44.8 46.8 45.0 43.8 51.7 46.8 49.6 52.1 50.6 Lowfrequent 39.7 43.0 45.3 46.0 44.4 48.6 47.1 49.4 50.6 49.7 High 40.3 44.1 45.7 45.1 43.0 48.8 46.9 48.8 50.1 50.6 _Si_gnificance ns ns ns ns ns ns ns ns ns ns Cultivation Oxlyr" 42.6 47.0 48.2 46.1 45.9 50.8 48.8 50.5 52.0 52.0 2x/yr" 38.0 40.9 43.6 44.6 41.6 48.6 45.0 48.1 49.8 48.5 Significance tit it. fit. ns it. ns iii *0 i *t. # of Games - - - - 5 10 14 18 22 25 * ,** ,*** Significant at the O. 10. 0. 05, and 0. 01 probability levels, respectively. Ns Not significant at the 0.10 probability level. ISurface hardness was measured using the Clegg Impact Soil Tester In gravity deceleration (Gmax) I Low infrequent fertilizer- - 25 g N m2 year Iwith 5 applications; Low frequent- - 25 g N m'2 year Iwith 8 applications; High= 35 g N m2 year Iwith 7 applications. 22 Table 9. Significance of treatment effects and Brinkman traffic on turfgrass Eijelkamp shear strength (Nm)I on a Poa pratensis/Lolium perenne turf stand, East Lansing, MI. 1999-2000. _ 1999— 2000 10/1 11/15 5/15 6/15 7/15 8/15 9/15 10/15 11/15 5 Mowing 1x/week 13.5 14.4 17.4 19.0 17.9 20.0 22.6 24.1 15.3 2xlweek 13.7 14.2 16.8 19.2 18.4 21.4 22.5 24.4 16.0 Significance na na ns ns ns * ns ns ns FertilizationI Low infrequent 13.0 13.2 16.7 19.4 17.8 20.0 22.2 22.2 14.9 Lowfrequent 13.7 16.1 16.6 18.1 18.1 21.6 23.5 26.4 17.2 High 14.1 13.7 18.0 20.0 18.5 20.2 22.1 24.1 14.9 _S_ignificance ns ns ns ** ns ns ns *“ ‘ Cultivation Oxlyr" 13.8 14.1 17.8 20.4 19.1 21.7 23.3 25.0 15.2 2x/yr" 13.4 14.6 16.4 17.8 17.1 19.5 21.9 23.4 16.1 Significance na na " “* *“ ** “ ns ns # of Games - - - - - 7 15 25 " ,“ ,*“ Significant at the 0. 10, 0. 05, and 0. 01 probability levels, respectively. Ns Not significant at the 0.10 probability level. Na Not applicable, prior to treatment application. I Shear strength was measured using2 the Eijelkamp Shear vane in Newton meters (Nm). ILow infrequent fertilizer- - 25 g N m2 year with 5 applications; Low frequent- '- 25 g N m2 year Iwith 8 applications, High= 35 g N m2 year 1with 7 applications. Table 10. Significance of treatment effects and Brinkman traffic on turfgrass Eijelkamp shear strengthI on a Poa pratensis/Lolium perenne turf stand, East Lansing, MI. 2001. 5/15 6/15 7/15 8/25 9/12 10/01 10/15 10/26 11/09 11/16 Mowing 1x/week 26.0 21.2 20.3 14.4 18.7 17.6 17.0 18.1 13.4 12.1 2xlweek 25.9 21.4 20.7 14.8 17.6 17.3 16.8 17.3 13.0 11.7 ignificance ns ns ns * “ ns ns ns ns ns Fertilization Low Infrequent 23.6 20.7 19.9 14.4 18.3 16.9 16.1 17.7 13.0 11.7 Lowfrequent 27.3 22.1 20.9 14.8 18.2 17.6 17.0 18.0 13.5 11.9 High 26.9 21.1 20.6 14.7 17.9 17.8 17.6 17.3 13.1 12.1 _S_ignificance ns ns ns ns ns * " ns ns ns Cultivation OxlyrI 26.4 22.4 21.3 15.2 18.4 17.2 17.0 17.1 13.1 12.0 2x/yr" 25.5 20.3 19.6 14.0 17.9 17.7 16.9 18.3 13.3 11.8 Significance ns “* *“ ‘“ ns ns ns “ ns ns # of Games - - - - 5 10 14 18 22 25 *, ** ,"’** Significant at the 0. 10, 0. 05, and 0. 01 probability levels, respectively. Ns Not significant at the 0.10 probability level. I Shear strength was measured using2 the Eijelkamp Shear vane in Newton meters (Nm). I Low infrequent fertilizer - 25 g N m2 ear with 5 applications, Low frequent- " 25 g N m2 year‘1 with 8 applications; High= 35 g N m year Iwith 7 applications. 23 difference between ratings should be greater then 5 Nm (Stier and Rogers, 2001) Shear clegg Although plots mown once per week had statistically higher shear/Clegg ratings then plots mown twice per week, (23.5 vs. 20.4), further research is warranted to make any definite conclusions. Given this effect only occurred at this rating date, the differences between ratings was very small, and that plant counts and turfgrass cover were higher on plots mown twice per week (Tables 4 and 6), the reason for differences is most likely chance by sampling location rather then mowing frequency (Table 11). Quality Mowing once per week had a higher quality rating then mowing twice per week in July of 2000. Although these ratings were statistically significant, the actual ratings of 7.8 and 7.6 for the low and high mowing frequencies respectively, did not differ enough to warrant discussion of cultivation effects on turfgrass quality for this date. Because the ratings were qualitative and only occurred once, the difference was probably incidental. However, mowing twice per week had a higher quality rating then mowing once per week from November 2000 through June of 2001 and again on 01 October through November 2001 (Tables 12 and 13). This effect probably occurred because the increased mowing frequency caused the older leaf tissue to be removed and newer leaf tissue to emerge. Thus mowing, in combination 24 Table 11. Significance of treatment effects and Brinkman traffic on turfgrass Clegglshear strength (Nm)I on a Poe pratensIs/Lolium perenne turf stand, East Lansing, MI. 2001. 9/12 10/01 10/15 10/26 11/09 11/16 Mowing 1x/week 22.4 30.5 22.6 23.5 27.8 27.4 2xlweek 21.5 30.2 22.6 20.4 27.7 26.4 Significance ns ns ns '“ ns ns FertilizationI Low infrequent 23.2 32.6 24.4 23.4 28.5 26.9 Low frequent 22.3 29.2 22.6 21.9 27.7 27.4 High 20.4 29.3 20.8 20.5 27.0 26.4 _ggnificance ns ** ns * ns ns Cultivation Oxlyr'I 21.0 31.5 23.1 21.1 27.5 27.3 2x/yrI 22.9 29.2 22.1 22.8 27.9 26.5 Significance ns “ ns ns ns ns # of Games 5 10 14 18 22 25 ‘ ,,** *“ Significant at the 0.10.0. 05, and 0. 01 probability levels, respectively. Ns Not significant at the 0.10 probability level. I Shear strength was measured using2 the shear/Clegg In Newton meters. I Low infrequent fertilizer- - 25 g N m'2 year Iwith 5 applications; Low frequent-— " 25 g N m2 year with 8 applications, High= 35 g N m'2 year Iwith 7 applications. -1 25 Table 12. Significance of treatment effects and Brinkman traffic on turfgrass qualityI on a Poa pratensis/Lolium perenne turf stand, East Lansing, MI. 1999-2000. __ 1999_ 2000 10/15 11/15 5/15 6/15 7l15 8/15 9/15 10/15 11/15 Mowing 1x/week 6.8 6.2 5.9 7.8 7.8 7.3 7.5 6.3 6.4 2xlweek 6.4 5.9 5.8 8.0 7.6 7.3 7.3 6.5 7.2 Significance na na ns ns “ ns ns ns *“ FertilizationI Low infrequent 6.3 6.0 5.3 7.5 7.1 6.8 7.0 5.6 6.3 Low frequent 7.0 6.4 6.6 8.5 7.9 7.5 7.3 6.6 6.9 High 6.6 5.8 5.5 7.8 8.1 7.7 7.9 6.9 7.2 _SiJniflcance tit iii it! it. fit. ns iii 1*. tit Cultivation OxlyrI 6.7 6.0 5.9 7.9 7.7 7.3 7.4 6.3 6.7 2x/yrI 6.6 6.1 5.8 7.9 7.7 7.3 7.4 6.5 6.8 Significance na na ns ns ns ns ns ns ns # of Games - - - - - - 7 15 25 * ," ,“' Significant at the 0. 10, 0. 05, and 0. 01 probability levels, respectively. Ns Not significant at the 0.10 probability level. Na Not applicable, pn'or to treatment application. IQuality was rated visually on a 1-9 scale. 1=necrotic turf/bare soil, 9=dense, uniform turf with acceptable color (color_ > 5). ILow infrequent fertilizer - 25 g N m2 year Iwith 5 applications; Low frequent- - 25 g N m2 year’I with 8 applications; High= 35 g N m year Iwith 7 applications. Table 13. Significance of treatment effects and Brinkman traffic on turfgrass qualityI on a Poa pratensis/Lolium perenne turf stand, East Lansing, MI. 2001. 5/15 6/15 7/15 8/25 9/12 10/01 10/15 10/26 11/09 11/16 Mowing 1x/week 6.6 7.1 8.0 8.6 8.5 7.0 6.6 6.3 5.1 5.5 2xlweek 7.1 7.6 8.0 8.7 8.5 7.5 7.0 7.0 6.3 6.3 Significance it! it. ns ns ns ii. iii it. fit. it. FertilizationI Low infrequent 6.4 7.0 8.0 8.8 8.5 6.9 6.3 6.0 5.3 5.8 Low frequent 7.2 7.4 8.0 8.6 8.5 6.9 6.5 6.5 5.4 5.3 High 7.0 7.7 8.0 8.6 8.5 7.9 7.6 7.5 6.4 6.5 finiflcance it. it. ns ns ns *1. iii tit iii if! Cultivation Oxlyr'I 6.8 7.3 8.0 8.6 8.5 7.2 6.6 6.4 5.7 5.8 2x/yrI 7.0 7.4 8.0 8.7 8.5 7.3 7.0 6.8 5.7 6.0 Significance ns ns ns ns ns ns “ “ ns ns # of Games - - - 5 10 14 18 22 25 * ," ,*" Significant at the 0.10, 0. 05, and 0. 01 probability levels, respectively. Ns Not significant at the 0. 10 probability level. I Quality was rated visually on a_ 1 -9 scale: 1=necrotic turf/bare soil, 9: dense, uniform turf with acceptable color (color_ > 5). I Low infrequent fertilizer- - 25 g N m2 year 1with 5 applications; Low frequent- - 25 g N m2 yearI with 8 applications; High= 35 g N m year Iwith 7 applications. 26 with traffic, likely stimulated more growth, resulting in greater turfgrass cover (Table 4 and 6), which provided a more uniform turf appearance. There was probably no significance between treatments during July, August, and mid- September because traffic simulation had not begun. Color Although statistical significance occurred between color ratings in August (7.2, 6.8), September (7.4, 7.7), and October of 2000 (6.2, 6.5), and June (7.3, 7.6) and November (4.3, 4.6) of 2001 the actual difference between ratings is not enough to warrant further discussion or acceptation of statistical significance (Tables 14 and 15). However, the 15 November 2000 (7.0, 7.7), and the July (7.1, 7.7), August (7.8, 8.2) and September 2001 (6.6, 7.2) ratings varied enough to warrant discussion (color ratings taken after June of 2001 were done quantitatively with the SpectrumTM FieldScout chlorophyll meter--Spectrum Technologies, Inc., Plainfield, IL). In November of 2000 and July, August, and September of 2001, color ratings were higher for plots mown twice per week. The ratings may have been higher for these plots on these dates because the increased mowing frequency caused the older leaf tissue to be removed and newer leaf tissue to emerge; thereby causing the color to appear darker. Fertilization Plant counts 27 Table 14. Significance of treatment effects and Brinkman traffic on turfgrass colorI on a Poa pratensis/Lolium perenne turf stand, East Lansing, MI. 1999-2000. — 1999 2000 10/15 11/15 5/15 6/15 7/15 8/15 9/15 10/15 11/15 Mowing 1x/week 6.6 6.3 6.3 7.9 7.1 7.2 7.7 6.2 7.0 2xlweek 6.6 6.3 6.2 8.0 7.2 6.8 7.4 6.5 7.7 Signi Ificance na na ns ns ns “ “ " '" FertilizationI Low infrequent 6.3 6.0 5.6 7.8 6.8 6.3 7.3 5.8 6.9 Low frequent 7.3 6.8 7.3 8.3 7.0 7.2 7.4 6.5 7.6 High 6.3 6.0 5.9 7.8 7.6 7.5 8.0 6.8 7.5 Si gnificance tit it! it. ii! iii tfifi it. tit it! Cultivation . OxlyrI 6.6 6.3 6.3 8.0 7.1 6.9 7.5 6.4 7.3 2x/yrI 6.7 6.3 6.3 8.0 7.2 7.1 7.7 6.4 7.4 Significance na na ns ns ns ns * ns ns # of Games - - - - - - 7 15 25 * ,*‘ ,*** Significant at the 0. 10, 0. 05, and 0. 01 probability levels, respectively. Ns Not significant at the 0.10 probability level. Na Not applicable, prior to treatment application. I Color was rated visually on a 1-9 scale: 1 = dead/no turf, 9= uniform dark green turf. LIow infrequent fertilizer- '- 25 g N m'2 year Iwith 5 applications; Low frequent- - 25 g N m2 yearI with 8 applications; High= 35 g N m year Iwith 7 applications. Table 15. Significance of treatment effects and Brinkman traffic on turfgrass colorI on a Pea pratensis/Lolium perenne turf stand, East Lansing, MI. 2001. 5/15 6/15 7/15 8/25 9/12 10/01 10/15 10/26 11/09 11/16 Mowing 1x/week 6.9 7.3 7.1 7.8 6.6 6.7 6.3 5.8 4.5 4.3 2xlweek 7.1 7.6 7.7 8.2 7.2 7.2 6.6 6.0 4.7 4.6 Signi Ificance ns m " m ”’ ns ns Ns ns *“ FertilizationI Low infrequent 6.5 7.0 7.1 7.8 6.9 6.3 5.9 5.4 4.3 4.3 Low frequent 7.3 7.5 7.1 8.0 6.7 7.0 6.5 6.0 4.3 4.2 High 7.2 7.8 7.9 8.2 7.1 7.7 7.0 6.3 5.2 4.9 Significance .0! it. it. ns ns It! fit. it it it. Cultivation OxlyrI 6.9 7.5 7.3 7.9 6.9 6.8 6.3 5.8 4.4 4.4 2x/yrI 7.1 7.4 7.4 8.1 7.0 7.1 6.5 6.0 4.8 4.5 Significance “ ns ns ns ns ns ns Ns ns ns # of Games - - - 5 10 14 18 22 25 * ,“ ,*** Significant at the 0. 10.0.05, and 0. 01 probability levels, respectively. Ns Not significant at the 0. 10 probability level. I October 2000 through June 2001 color was rated visually on a 1 -9 scale. 1 = dead/no turf, 9 - uniform dark green turf. July through November 2001 color was rated using the Spectrum“ FieldScout chlorophyll meter (Spectrum Technologies, Inc., Plainfield, IL). I Low infrequent fertilizer" - 25 g N m2 year Iwith 5 applications; Low frequent - 25 g N m2 yearI with 8 applications; High= 35 g N m year Iwith 7 applications. 28 Fertilizing at the low frequent (LF) rate gave a 16 % increase in plant counts over fertilizing at the low infrequent (LIF) rate in June of 2001. Fertilizing at the high (HF) rate of fertilizer yielded a 24 % increase in plant counts over theLlF rate of fertilizer on 16 November 2001 (Table 4). The reason the LF rate of fertilizer showed an increase in plant counts over plants fertilized at the LIF level in June of 2001 could be because the plants in the LF fertilizer regime were getting the nitrogen needed for growth more frequently. Although plots in the LIF regime were getting more nutrients per application, they were not getting the nutrients as frequently (plots in the LlF regime had 1 application, plots in the LF regime had 4 applications and plots in the HF regime had 2 applications). Thus, the LIF level of fertilizer may provide enough annual nitrogen, but in a sand rootzone, the nutrients are not held in the soil long enough to be readily available for plant absorption (Rogers et al., 1996). In November, continued traffic simulation caused the variance between treatments to lessen. By the last rating date, only plants receiving the HF level of fertilizer had higher plant counts then plants receiving the LIF regime (Table 4). Plants in the LF fertilizer regime had higher plant counts then plants in the LIF regime however, the difference was not significant. The reason plant counts were highest in the high fertilizer regime could be because plants needed more nutrients with each application to withstand the wear. In addition, by the end of traffic simulation, plants in the HF fertilizer regime only had one less fertilizer application. Because application frequencies were similar by the 16 November 29 2001 rating date, the increase in plant counts could most likely be due to fertilizer amount rather then fertilizer frequency. Turfgrass cover In May and June of 2000, fertilizing at the LF rate had a higher turfgrass cover rating then fertilizing at either the low infrequent or HF rate. Also in June of 2000, the HF rate of fertilizer gave a higher turf cover rating then the LIF rate of fertilizer. This occurred again on 01 October of 2001. Both the LF and HF rate of fertilizer gave higher turfgrass cover ratings then the LIF rate in July and 13 October through 15 November of 2000 and again in May and June of 2001. Fertilizing at the LF rate yielded higher turf cover ratings then just the LIF rate in July of 2001. The HF rate of fertilizer gave higher turfgrass cover ratings then either of the other two fertilizer levels beginning on 15 October and continuing through 16 November 2001 (Tables 5 and 6). Although statistical significance occurred for fertilizing at the LIF, LF and HF rate in June (95, 99, 97) and July (97, 99, 99) of 2000 and June (88, 93, 92) and July of 2001 (97, 100, 99), the actual difference in qualitative ratings of turfgrass cover between treatments on these dates do not vary enough to warrant further discussion or acceptation of statistical significance. In May of 2000, the LF level of fertilizer increased turfgrass cover by at least 9% over either of the other two levels most likely because plots in this regime were the only ones to receive fertilizer by this rating date. Therefore, 30 these plots appeared denser. After all plots received an application, the effect diminished. On 13 October 2000 and continuing through 15 May 2001 both the LF and the HF level of fertilizer yielded a 9-26% increase in turfgrass ratings then the LIF rate of fertilizer. The reason both levels of fertilizer were more effective at increasing density then the LIF level could be because for both of these levels, nutrients were provided on a fairly frequent basis. Given this, perhaps fertilizing at the LF rate is just as beneficial to the plant as fertilizing at the HF rate. The lesser amount, yet higher frequency of application in the LF fertilizer regime may have provided plants with adequate available nutrients so they were just as healthy as plants fertilized at the HF level. Therefore, fertilizing at the low rate is enough for annual nitrogen requirements; however, because this study was on a sand based rootzone, the light and more frequent fertilizer applications are necessary. This effect was somewhat modified in 01 October 2001, when the HF fertilizer level increased turfgrass cover by 8% over the LIF fertilizer levels. Continuing with this effect, beginning on the next rating date and continuing through the rest of traffic simulation, the HF fertilizer level had higher turfgrass cover ratings then either of the other fertilizer levels. The reason the effect of fertilizer level was modified from 2000 may be because a half-pound of nitrogen per application did not provide enough nutrients for plants in the second year of intense traffic. Similar results were also found for the Cady traffic simulation. 31 This data shows that by fertilizing at the HF rate, the turfgrass will at least appear to be denser for an additional 30 passes. Surface Hardness Fertilizing at the LF rate yielded a lower surface hardness then fertilizing at either the HF or LIF rate in May through August of 2000 (Tables 7 and 8). The LF rate of fertilizer yielded lower surface hardness ratings on these dates because the higher frequency of fertilizer application may have caused plants in this regime to have increased shoot growth (Juska, 1967; Johnston, 1984). The increased shoot growth provided for a slight increase in turfgrass cover, which previous research has shown to have an inverse relationship with surface hardness (Rogers et al., 1988). This could have caused a slight decrease in surface hardness ratings. However, once traffic began these effects were indiscernible. Shearvane Statistical significance occurred for the UP, LF, and HF fertilizer levels in June of 2000 (19.4, 18.1 and 20.0), 01 October (16.9, 17.6, and 17.8) and 15 October of 2001 (16.1, 17.0, and 17.6) (Tables 9 and 10). However, because the actual difference between shear strength ratings were so small, it is inconclusive whether or not fertilizer rate and frequency had an effect on shear vane ratings. However, the October and November 2000 ratings did vary enough to show a slight trend. In October, the LF fertilizer had higher shear strength ratings 32 then the LIF level and in November the LF level had higher ratings then either of the other fertilizer levels. This could be because plots in the LF and HF fertilizer regime had higher turfgrass cover over plots in the LIF fertilizer regime (Table 5). In addition, the increased frequency of fertilizer application potentially increased rooting and shoot growth (Kussow, 2000; Bredakis and Roberts, 1959). Therefore, when rotational shear strength was measured, plants in the LF regime yielded higher ratings (Tables 9 and 10). These results are supported by previous athletic turfgrass research which has demonstrated that increased turf cover leads to increased rooting (Rogers et al., 1988) and that rooting has a considerable effect on turfgrass shear strength-especially in sand root zones (Chen et al., 1980). Thus, plants in the LF fertilizer regime benefited from fertilizer being supplied on a frequent basis; the overall health of these plants was maintained, even at lower nitrogen levels. Shear/clegg Fertilizing at the LIF rate gave a higher shear strength rating then fertilizing at either the LF or the HF rate of fertilizer on 01 October 2001 and a higher shear strength ratings then fertilizing at the HF rate on 26 October 2001 (Table 11). Although the LIF rate of fertilizer had increased shear/Clegg ratings for two sampling dates, the increase was minimal. However, a possible reason for the LIF fertilizer rate having higher shear strength ratings may be because of increased rooting and shoot growth (Bredakis and Roberts, 1959; Juska, 1967). 33 The reason the shear/Clegg ratings showed different statistical significance between fertilizer treatments then the shear vane could be because the shear/Clegg measures lateral shear strength, which is more of a reflection on rooting depth while the shear vane measures rotational shear strength, which is more of a reflection on plant and plant tiller tensile strength. Quality Fertilizer levels had a significant effect on quality ratings at almost all of the ratings dates (Tables 12 and 13). However, there was little consistancy between ratings. At times, the LIF had the highest ratings, but the majority of the time, either the LP or the HF rate of fertilizer had higher ratings. This was probably due to the increased frequency of applications for both of these levels over the LIF level; quality ratings were often taken shortly after fertilizer applications. In addition, in Michigan, October is typically the end of the optimal growing season for cool season turfgrasses and any additional nutrients would improve turfgrass growing conditions-especially considering that these plants were being grown in a sand rootzone (Baker and Jung, 1968). As a result, plants receiving more fertilizer appeared to be healthier. Color Similar to quality ratings, fertilizer level almost always had an effect on turfgrass color (Table 14 and 15). Most frequently, the HF fertilizer level rating was similar to the LF level and higher then the LIF level. This could be because 34 plants were getting more of the nutrients they needed when they needed them- especially considering that these plants were being grown in a sand rootzone. In Michigan, October is typically the end of the optimal growing season for cool season turfgrasses. Therefore, any additional nutrients will improve turfgrass growing conditions, thereby making the plants appear healthier and more vibrant (Baker and Jung, 1968). Plots fertilized at the LIF level had lower color ratings because although they received as much fertilizer per application as did plots at the HF level, the accumulated amount and frequency was lower. In addition, plots fertilized at the LF and HF level received fertilizer more frequently then plots fertilized at the LIF level. Hence, when color ratings were taken, these plots had usually just received a fertilizer application (Table 3). Cultivation Plant counts Cultivation had no effect of plant counts throughout the study (Table 4). Cultivation did not have an effect on plant counts because the study was on a three-year old, sand based root zone field. The field was probably not compacted enough to effect turfgrass growth; therefore, differences in plant counts were not significant. In addition, cultivation was done at the end of traffic simulation and again in the early spring. Thus, when plant counts were taken, almost four months had passed since the plots had been cultivated. Therefore, any long-term cultivation benefits were not attained for an increase in plant counts. 35 Turfgrass cover Statistical significance occurred between cover ratings on 26 October (67 and 72%), 09 November (52 and 56%) and the 16 November of 2001 (37 and 42%) for the low and high cultivation frequencies respectively (Tables 5 and 6). However, because the difference between ratings was minimal, it is inconclusive as to whether or not cultivation had an effect on turfgrass cover. Consequently, because the ratings were qualitative, the effect only occurred once, and the variance did not show in plant counts (Table 4), the difference was probably incidental. However, more investigation is warranted because this data, although weak, does show the potential for cultivation frequency to extend turfgrass cover for at least an additional 6 traffic applications. Surface Hardness Cultivating twice per year decreased surface hardness from June through November of 2000 and again in May through July, September, and 15 October through November of 2001 (Tables 5 and 6). This effect was seen because cultivation directly affects soil conditions; therefore it has the potential to greatly influence surface characteristics, as it did on these rating dates. This result was also seen on Poa pratensis and Festuca arundinacea in a study done by Rogers and Waddington (1990). However, by November 2000 and 26 October 2001, although statistically significant, the difference in ratings between treatments was minimal; this could be because the effects of traffic made the soil conditions more uniform. These results potentially show that for 2000, surface hardness can be 36 lowered by cultivating twice per year for an additional 25 games and, for 2001, surface hardness conditions can be lowered for an additional 10 games. Shearvane Statistical significance occurred between shear strength ratings in May through September 2000 and June through August 2001 (Tables 9 and 10). However because the difference between ratings was small, it is inconclusive as to whether or not cultivation frequency effects shear vane ratings. Previous research has shown that for treatment effects to be truly significant, the difference between ratings should be greater then five (Stier and Rogers, 2001). Even though differences between treatments were small, more research is warranted because it does appear that cultivation does lower shear strength until traffic simulation begins. This trend was seen at every rating date with the exception of 26 October 2001. However, these ratings were also too similar to regard as truly being significant. Shear/clegg Statistical significance occurred between shear/Clegg ratings on 01 October 2001 (31.5 and 29.2) for the low and high cultivation frequencies respectively (Table 11). However, because the difference between ratings was minimal, it is inconclusive if cultivation frequency had and effect on shear/Clegg ratings. 37 However, more investigation is warranted because this occurrence although weak, supports the theory also found in the Cady and native soil results’ shear vane ratings that cultivating lowers shear strength. Quality Although statistical significance occurred for quality ratings between plots cultivated twice per year versus not cultivated on 15 October (6.6, 7.0), and 26 October of 2001 (7.4, 7.8), the actual difference between numbers for qualitative quality ratings is not enough to warrant further discussion or acceptation of statistical significance (Table 13). Color Although statistical significance occurred for color ratings between plots cultivated twice per year versus not cultivated in September of 2000 (7.5, 7.7), and May of 2001 (6.9, 7.1), the actual difference between numbers for qualitative color ratings is not enough to warrant further discussion or acceptation of statistical significance (Tables 14 and 15). Mowing x Fertilization Interaction In August of 2001, plots mown once per week had higher shear strength ratings if they were fertilized at the LF level then if they were fertilized at either the LIF or the HF level. If plots were mown twice per week, fertilizer rate and frequency did not have an effect. However, the difference between ratings was minimal and this was the only date that this effect occurred (Table 16). 38 Table 16. Significance of the Interaction of mowing frequency, fertilizing rate and frequency and Brinkman traffic on turfgrass Eijelkamp shear strengthI on a Poa pratensis/Lolium perenne turf stand, East Lansing, MI. 2001 8/15 Mowing x FertilizingI 1x/week, Low infrequent 13.9 1x/week, Low frequent 15.1 1x/week, High 14.3 2xlweek, Low infrequent 14.8 2xlweek, Low frequent 14.6 2xlweek, High 15.0 LSD(o.05) 0.7 # of Passes - j Shear strength was measured using2 the Eijelkamp Shear Vane In Newton meters (Nm). I Low infrequent fertilizer- - 25 g N m2 ear with 5 applications, Low frequent- - 25 g N m2 yearI with 8 applications; High= 35 g N m year Iwith 7 applications. 39 Mowing x Cultivation Interaction If plots were mown once per week, cultivation lowered shear vane and surface hardness ratings. lf plots were mown twice per week cultivation increased quality and shear/Clegg ratings. However, the differences between ratings were minimal and these ratings were isolated (Table 17). Fertilization x Cultivation Interaction In August of 2001, not cultivated had higher shear vane ratings if they were fertilized at the HF level, as compared to the other two levels of fertilizer. However, if plots were cultivated, plots fertilized at the HF level had lower shear vane ratings then plots fertilized at the other two fertilizer levels. However, difference between ratings was minimal and these ratings were all isolated (Table 18). In terms of shear/Clegg ratings, plots fertilized at the LIF level and cultivated twice per year had higher shear/Clegg ratings if they were fertilized at the same level and not cultivated. If plots were fertilized at either of the other two levels, cultivating twice per year yielded lower shear/Clegg ratings-although not significantly lower. l-lowever, similar to the shear vane ratings, differences between ratings were minimal and this was an isolated observation (Table 18). Mowing x Fertilization x Cultivation A three-way interaction occurred for turfgrass cover ratings on 16 November 2001. This interaction shows that cultivation by itself does not lead to increased turfgrass cover late in the season. However, cultivation seems to act 40 Table 17. Significance of the interaction of mowing, cultivatln "’19 and Brinkman traffic on turfgrass Eijelkamp and Clegg/shear shear strength , surface hardnessI, and qualityI on a Poa pratensis/Lollum perenne turf stand, East Lansing, MI. 2000- 01. Shear Surface Quality Shear/Clegg Vane (Nm) Hardness (Gum) (Nm) 2000—— —— 2001 8/15 10/15 10/15 10/26 Mowing x Cultivating 1x/week, Low 21.8 69.1 6.6 23.6 1x/week, High 17.7 59.6 6.5 23.5 2xlweek, Low 21.6 61.5 6.7 18.6 2xlweek, High 21.3 63.3 7.4 22.1 LSD(0,05, 2.6 6.4 0.62 2.4" # of Games - 15 15 19 Shear strength was measured using the Eijelkamp Shear Vane In Newton meters (Nm). IShear strength was also measured using the shear/Clegg In Newton meters. ISurface hardness was measured using the Clegg Impact Soil Tester In gravity deceleration (Gm). IQuality was rated visually on a 1-9 scale: 1=necrotic turf/bare soil, 9=dense, uniform turf with acceptable color (color_ > 5). I:I‘Significant to the 0. 01 value. SignIf cant to the 0.10 value. Table 18. Significance of the interaction of fertilizingt cultivating, and Brinkman traffic on turfgrass Eijelkamp and Clegg/shear shear strength on a Poa pratensis/Lolium perenne turf stand, East Lansing, MI. 2001 Shear Vane (Nm) Shear/Clegg (Nm) 8/15 11/9 FertilizingI x Cultivating Low infrequent, Low 14.6 26.2 Low frequent, Low 15.3 28.6 High, Low 15.8 27.8 Low infrequent, High 14.2 30.9 Low frequent, High 14.3 26.8 High, High 13.6 26.2 LSD(0_05) 0.7 3.3 # of Games - 22 I Shear strength was measured using the Eijelkamp Shear Vane In Newton meters (Nm). I Shear strength was also measured using the shear/Clegg In Newton meters. I Low infrequent fertilizer - 25 g N m2 year Iwith 5 applications, Low frequent- " 25 g N m2 yearI with 8 applications; High= 35 g N m year Iwith 7 applications. 41 as a catalyst for mowing and/or fertilizing applications to increase turfgrass cover. Thus, cultivation, in combination with either the low mow/HF fertilizer treatment or the high mow/LF or HF fertilizer treatment, did increase turfgrass cover. Furthermore, if both mowing and fertilizing are applied at the high rate, there is not an increase in turfgrass cover. This is likely a result of the environmental and plant limitations. A three-way interaction also occurred for other ratings throughout the study. However, each of the observations were isolated, thus, no trend can be made (Table 19). Treatment Comparisons The highest and lowest level treatment regimes were compared to quantify the number of additional games gained from increased inputs. 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Em... .xss2 3.620 660 .560 66E sustaw 96> 6scw 62w 660 Seaémm.‘ ._2 $5.26.. 66m .966 E: 22661 52.046.66.93 col 6 so .6666: suntan E6 .uacsoo :6... (£636 £39.26 626 nEsx_s.._m is>oo mascots“ :o 026: 6.5.5.5 v.6 $562230 $55.36.— .mEBoE no :26225 65 no sonneEcmfi .3 s33. 43 1002 + N § 80 e 3 - \— vL : 4 t 60 +Low Infrequent .3 l +Low Frequent g 40 i +High o L Aug. Sept. 14 Oct. 13 Oct. 20 Oct. 27 Nov. 15 Games Simulated 0 7 14 18 22 25 Figure 3. Effect of fertilizer and Brinkman traffic on turfgrass cover over time, East Lansing Michigan, 2000 3 > 8 c: + Low Infrequent .3 + Low Frequent E + High § 0 a. Aug. Sept. 13 Oct. 01 Oct. 15 Oct. 26 Nov. 09 Nov. 16 Games Simulated 0 7 10 14 18 22 25 Figure 4. Effect of fertilizing and Brinkman traffic on turfgrass cover over time, East Lansing, MI, 2001 1001 80 60 f \ + 1xlweek ‘ +2x/week Percent Turf Cover Aug. Sep. 13 Oct. 01 Oct. 15 Oct. 26 Nov. 09 Nov. 16 Games Simulated 0 7 10 14 18 22 25 Figure 5. Effect of mowing and Brinkman traffic on turfgrass cover over time, East Lansing Michigan, 2001 44 Results and Discussion Cady Traffic Simulator Results and discussion are divided by maintenance practice and then subdivided by the effect each practice had on the evaluation criteria. Interaction results and discussion are at the end. We designated surface hardness measurements between treatments to be inconclusive if differences were less then 5 gm. In general, ratings decreased faster with the Cady traffic simulator as opposed to the Brinkman traffic simulator. The only exceptions were shear strength ratings, which remained similar and surface hardness ratings, which increased. Comparisons between treatments for plant count and percent cover ratings are listed in Appendix C. A cost analysis for each treatment is also listed in Appendix C. Mowing Plant counts Plots mown twice per week gave a 9-15 % increase in plant counts over plots mown once per week on August through 15 October 2001 and again on 09 November 2001 (Table 20). The higher number of plant counts may have occurred at the high mowing level because mowing, at the proper height and frequency, stimulates shoot growth and tillering (Juska, 1961; Crider, 1955). Thus, the increased mowing frequency resulted in increased tillering and shoot production causing an increase in plant counts. Furthermore, if more then 30% of the leaf blade of a plant is removed in a single mowing, the all or nearly all of the plants energy goes into shoot production and negligible amounts, if any go 45 Table 20. Significance of treatment effects and Cady traffic on plant countst on a Poa pratensis/Lolium perenne turf stand, East Lansing, MI. 2001 8/25 10/01 10/15 10/26 11/09 11/16 Mowing 1x/week 171.1 163.0 115.1 97.7 80.3 57.9 2xlweek 201.6 188.4 129.4 103.9 88.7 69.9 flgnificance ** *“ ' * ns * ns Fertilization‘ Low infrequent 178.5 148.3 103.5 93.8 79.2 64.2 Low frequent 191.0 185.8 129.2 99.0 80.2 66.7 High 189.6 193.1 134.0 109.7 94.1 60.8 Significance ns **‘ “* ns ns ns Cultivation 0x/yr’1185.9 181.9 119.2 98.2 83.1 58.3 2x/yr 186.8 169.4 125.2 103.5 85.9 69.4 Significance ns ns ns ns ns ns # of Passes - 20 30 38 44 50 *, **, *“ Significant at the 0. 10, 0. 05, and 0. 01 probability levels, respectively. Ns Not Significant at the 0.10 probability level. :Plant counts were hand counted using three subsamples per treatment. Low infrequent fertilizer- - 25 g N rn'2 year with 5 applications; Low frequent“ - 25 g N m 2'year' with 8 applications; High= 35 g N m year with 7 applications. 46 into root, rhizome, or tiller initiation (Crider, 1955). As a result, it follows that once traffic simulation began, the root systems of the plants mown once per week may have been weaker then the root systems of the plants mown twice per week, because all of their energy was probably being put towards shoot development as opposed to tillering. Therefore, when subjected to traffic simulation, plants were removed from the ground much more easily causing a decrease in plant counts. Turfgrass cover Plots mown twice per week yielded at least a 3% increase in turfgrass cover over plots mown once per week on 01 October and 09 and 16 November 2001 (Table 21). These results mirror what was seen in plant count ratings. Thus, similar to plant counts, this effect most likely occurred as a result of a weakened root system. As a result, it follows that when subjected to traffic simulation, plants were removed from the ground much more easily causing a decrease in plant counts and visual decrease in turfgrass cover (Table 20). Between the rating dates of 01 and 15 October, there was a drop in turfgrass cover ratings in plots mown twice per week. This may have been because the optimal growth period for recovery worsened while traffic simulation continued. Finally, although statistically significant the 16 November ratings of 12 and 15% for the low and high mowing frequencies respectively, did not differ enough to warrant discussion or acceptation of statistical significance. 47 Table 21. Significance of treatment effects and Cady traffic on turfgrass coverT on a Poa pratensis/Lolium perenne turf stand, East Lansing, MI. 2001 8/25 10/01 10/15 10/26 11/09 11/16 Mowing 1x/week 100 49 43 30 14 12 2xlweek 100 58 48 32 22 15 _Significance ns “* ns ns “* ‘ Fertilization‘ Low infrequent 100 50 42 28 17 13 Low frequent 100 52 43 31 18 1 3 High 100 60 51 35 20 15 _S_ignificance ns “* “ “* ns ns Cultivation Oxlyr" 100 52 44 31 17 13 2x/yr" 100 56 47 31 19 14 Significance ns “ ns ns ns ns # of Passes - 20 30 38 44 50 *, “, *“ Significant at the 0.10, 0.05, and 0.01 probability levels, respectively. Ns Not Significant at the 0.10 probability level. tTurf cover was visually estimated on a percent (0-100%) scale. * Low infrequent fertilizer = 25 g N m'zyear'1 with 5 applications; Low frequent = 25 g N m'2 year‘1 with 8 applications; High = 35 g N m' year’1 with 7 applications. 48 Surface hardness Mowing frequency did not have an effect on surface hardness ratings at any of the data collection dates (Table 22). If the field was severely compacted or if mowing frequency resulted in major differences in turfgrass cover, then mowing frequency may have an effect on surface hardness ratings. However, because this study was conducted on a three-year old sand based root zone field, compaction was not a major issue. In addition, although mowing frequency increased plant counts (Table 20), the increase was not so vast that it affected the surface conditions of the soil. Thus, mowing frequency did not have an effect on surface hardness ratings. Shearvane Mowing frequency did not have an effect on turfgrass shear strength except on 16 November 2001 when mowing once per week gave a higher shear vane reading then mowing twice per week (Table 23). This effect was probably seen because at the time of data collection, plants counts per unit area were 57.9 and 69.9 and shear vane ratings were 12.7 and 13.4, for plants mown once per week and twice per week respectively. Because there was such little turfgrass cover, getting an accurate rating was nearly impossible and, although the Eijelkamp shear vane ratings were statistically significant, the differences between ratings was so small, it is inconclusive if mowing frequency had an effect on shear vane ratings. Previous research has shown that for treatment effects to be truly significant, the difference between ratings should be greater 49 Table 22. Significance of treatment effects and Cady traffic on surface hardnesst on a Poa pratensis/Lolium perenne turf stand, East Lansing, MI. 2001 8/25 10/01 10/15 10/26 11/09 11/16 Mowing 1x/week 47.7 51.9 43.2 54.6 64.9 61.5 2xlweek 47.9 50.8 43.7 55.6 64.4 61.9 _S_ignificance ns ns ns ns ns ns FertilizationI Low infrequent 48.4 51.8 44.2 54.1 65.4 61.7 Low frequent 47.3 49.4 44.5 55.0 64.8 62.1 High 47.8 52.7 41.6 56.3 63.8 61.3 Significance ns “ ns ns ns ns Cultivation Oxlyr" 50.9 54.0 44.9 56.4 65.2 61.8 2x/yr" 44.7 48.6 42.0 53.9 64.1 61.6 Significance *“ m *' " ns ns # of Passes - 20 30 38 44 50 *, “, *” Significant at the 0.10, 0.05, and 0.01 probability levels, respectively. Ns Not Significant at the 0.10 probability level. ' Surface hardness was measured using the Clegg Impact Soil Tester in gravity deceleration (Gmax)° ’ Low infrequent fertilizer = 25 g N m'2 year" with 5 applications; Low frequent = 25 g N 111'2 year" with 8 applications; High = 35 g N m' year" with 7 applications. Table 23. Significance of treatment effects and Cady traffic on Eijelkamp shear strengtht on a Poa pratensis/Lolium perenne turf stand, East Lansing, Ml. 2001 8/25 10/01 10/15 10/26 11/09 11/16 Mowing 1x/week 18.6 19.1 18.8 18.4 14.2 13.4 2xlweek 21.4 18.8 18.6 18.0 13.8 12.7 _Significance ns ns ns ns ns “ Fertilization‘ Low infrequent 18.9 19.5 18.8 19.2 14.3 12.8 Low frequent 18.7 19.1 18.9 17.6 13.6 13.5 High 22.5 18.3 18.3 17.8 13.9 12.8 _fignificance ns ns ns " ns ns Cultivation Oxlyr" 21.9 19.1 19.1 18.3 14.8 13.9 2x/yr" 18.1 18.8 18.2 13.1 13.1 12.2 Significance ns ns ns ns '" m # of Passes - 20 30 38 44 50 *, “, “* Significant at the 0.10, 0.05, and 0.01 probability levels, respectively. Ns Not Significant at the 0.10 probability level. * Shear strength was measured using the Eijelkamp Shear vane in Newton meters (Nm). * Low infrequent fertilizer = 25 g N m' ear’ with 5 applications; Low frequent = 25 g N m'2 year" with 8 applications; High = 35 g N m' year" with 7 applications. 50 then five (Stier and Rogers, 2001). In addition because this was the only date that this difference occurred, the reason for differences is most likely chance by sampling location. Shear clegg Plots mown twice per week yielded higher shear/clegg ratings then plots mown only once per week on 25 August 2001 (Table 24). Plots mown twice per week may have had higher shear/clegg ratings because of higher numbers of plant counts (Table 20). Although August was the first date that the shear/clegg was used, this data implies that mowing twice per week increases the lateral shear strength of the grass. The reason there were no significant differences for shear vane readings for this date may be because the shear vane measures rotational shear strength and the shear/clegg measures lateral shear strength. Quality Mowing twice per week gave higher quality ratings then mowing once per week beginning 01 October and continuing through 16 November 2001 (Table 25). This effect may have been because the increased mowing frequency caused the older leaf tissue to be removed and newer leaf tissue to emerge. This caused the plants to appear healthier and more vibrant in color. In addition, because there were more plants per unit area (Table 20) in plots mown twice per week, individual plant damage (i.e. necrosis) was less noticeable and the quality to appeared higher. Furthermore, because this effect appeared after traffic 51 Table 24. Significance of treatment effects and Cady traffic on Clegglshear strength1 on 3 Pas pratensis/Lolium perenne turf stand, East Lansing, MI. 2001 8/25 10/01 10/15 10/26 11/09 11/16 Mowing 1x/week 20.5 37.4 29.3 25.1 32.0 28.6 2xlweek 25.9 36.5 32.6 25.6 31.0 29.2 _ggnificance “" ns ns Ns ns ns Fertilization Low infrequent 25.7 38.9 33.6 24.0 32.5 30.8 Low frequent 22.9 36.1 32.1 27.8 28.7 30.0 High 20.9 35.9 27.2 24.3 33.3 26.0 _Eignificance * ns ** Ns ns “ Cultivation Oxlyr" 22.7 38.7 30.5 23.8 33.2 29.6 2x/yr" 23.7 35.3 31.4 26.9 29.8 28.2 Significance ns ns ns * " ns # of Passes - 20 30 38 44 50 *, “, *“ Significant at the 0.10, 0. 05, and 0. 01 probability levels. respectively. Ns Not Significant at the 0.10 probability level. :Shear strength was measured usungz the shear/clegg In Newton meters (Nm). Low infrequent fertilizer - 25 g Nrn year with 5 applications, Low frequent- - 25 g N m'2 year" with 8 applications; High= 35 g N m year 1with 7 applications. Table 25. Significance of treatment effects and Cady traffic on turfgrass quality1 on a Poa pratensis/Lolium perenne turf stand, East Lansing, MI. 2001 8/25 10/01 10/15 10/26 11/09 11/16 Mowing 1x/week 8.6 3.9 3.7 3.4 1.9 2.5 2xlweek 8.7 4.6 4.2 3.8 2.5 3.0 Significance ns it it it! it. tit Fertilization Low infrequent 8.8 4.0 3.6 3.3 2.0 2.7 Low frequent 8.6 3.9 3.8 3.6 2.2 2.4 High 8.6 4.8 4.4 3.9 2.4 3.0 finificance "5 it ifit tit ! it Cultivation Oxlyr" 8.6 4.1 3.7 3.3 2.1 2.6 2x/yr" 8.7 4.4 4.2 3.8 2.3 2.8 Significance ns ns *‘ “" ns ns # of Passes - 20 30 38 44 50 *, “, *** Significant at the 0. 10, 0. 05, and 0. 01 probability levels, respectively. Ns Not Significant at the 0.10 probability level. 1Quality was rated visually on a 1—9 scale. 1=necrotic turf/bare soil, 9= dense, uniform turf with tacceptable color (color_ > 5). Low infrequent fertilizer- - 25 g N m'2 year1with 5 applications; Low frequent - 25 g N rn'2 year" with 8 applications; High= 35 g N m year 1with 7 applications. 52 simulation began, this data implies that mowing, in combination with traffic, stimulated higher wear tolerance and more growth, which resulted in greater turfgrass cover (Tables 20 and 21). This provided for a more uniform turf appearance, which resulted in greater turfgrass quality ratings. Color Mowing twice per week gave a higher color rating then mowing once per week in August of 2001 and again 15 October through 09 November 2001 (Table 26). Similar to quality ratings, plots mown twice per week may have had higher color ratings because the increased mowing frequency allowed older leaf tissue to be removed and newer leaf tissue to emerge and because the higher amount of plants per unit area (Table 20) caused individual plant damage to become (i.e. necrosis) less noticeable. In addition, by the end of traffic simulation, the environmental conditions were no longer optimal for turfgrass growth. This resulted in slow growth and slow recovery from damage. This could be why at the last rating date, there were no longer differences in turfgrass color. Fertilization Plant counts Plots fertilized at either the low frequent (LF) or high (HF) rate of fertilizer gave at least a 20% increase in higher plant counts over plots fertilized at the low infrequent (LIF) rate of fertilizer on 01 and 15 October 2001 (Table 20). This effect could have resulted because in Michigan, October is typically the end of 53 Table 26. Significance of treatment effects and Cady traffic on turfgrass color1 on a Poa pratensis/Lolium perenne turf stand, East Lansing, MI. 2001 8/25 10/01 10/15 10/26 11/09 11/16 Mowing 1x/week 7.8 4.9 4.6 4.3 3.1 3.3 2xlweek 8.2 5.2 4.9 4.6 3.4 3.4 Significance “ ns ' *“ *“ ns Fertilization’ Low infrequent 7.8 4.5 4.4 4.3 3.3 3.4 Low frequent 8.0 5.0 4.6 4.3 3.2 3.2 High 8.2 5.8 5.3 4.8 3.3 3.4 Significance ns “* “* *" ns ns Cultivation Oxlyr" 7.9 5.0 4.7 4.4 3.3 3.3 2x/yr" 8.1 5.2 4.8 4.5 3.3 3.4 Significance ns ns ns Ns ns ns # of Passes - 20 30 38 44 50 *, ", m Significant at the 0.10, 0.05, and 0.01 probability levels, respectively. Ns Not Significant at the 0.10 probability level. 1Co|or was rated using the SpectrumTM FieldScout chlorophyll meter (Spectrum Technologies, lnc., Plainfield, IL). 1 Low infrequent fertilizer = 25 g N m'2 year" with 5 applications; Low frequent = 25 g N m'2 year" with 8 applications; High = 35 g N m' year" with 7 applications. the optimal growing season for cool season turfgrasses. Therefore, any additional nutrients would probably improve turfgrass growing conditions- especially considering that these plants were being grown in a sand rootzone (Baker and Jung, 1968). Given this, perhaps fertilizing at the LF rate is just as beneficial to the plant as fertilizing at the HF rate. The lesser amount, yet higher frequency of application in the LF fertilizer regime may have provided plants with adequate available nutrients so they were just as hardy as plants fertilized at the HF level (Johnston, 1984). Furthermore, by 01 October 2001 traffic had been applied forjust over a month (20 passes). Thus, fertilizing at the LP or HF rate proved to extend the amount of plants per unit area for an additional 2 weeks (8 passes). However, with continued traffic (after 30 passes) the effects of fertilizer rate and frequency were no longer significant. Turfgrass cover Plots fertilized at the HF rate gave at least an 8% increase in turfgrass cover ratings over plots fertilized at either the LlF or the LF rate on 01 and 15 October 2001. On 26 October 2001, plots receiving the HF rate of fertilizer had a 7% increase in turfgrass cover over the plots receiving the LIF rate of fertilizer (Table 21). The reason plots fertilized at the HF level appeared to have higher turfgrass cover then plots fertilized at either the LIF or LF levels on 01 and 15 October may be because October is typically the end of the optimal growing season for cool season turfgrasses. Therefore, and additional nutrients would help increase turfgrass growth-especially considering that these plants were 55 being grown in a sand rootzone. Perhaps the HF level of fertilizer appeared to have higher turfgrass cover ratings because there were more nutrients available for the plants. Plots fertilized at the HF rate had, cumulatively, 25 g N m'2 while plots fertilized at either of the other two levels had only 15 g N m'z. Perhaps at the ratings dates, plots fertilized at the HF and the LF levels were deficient in nutrients which caused the plants to have decreased shoot density, and also a decrease in recuperative potential (Kussow, 2000). However, the plant count data indicates that both the HF and the LF fertilizer levels were equal in terms of quantitative density ratings. Therefore, more research is warranted to determine if both levels of fertilizer equally support increased turfgrass growth. By the 26 October rating date, plots at the LF level had the same turfgrass cover ratings as plots fertilized at the HF level while plots fertilized at the LIF level had lower turfgrass cover ratings then both of these plots. This occurrence may have been influenced by the fact that all plots had just gotten a 5 g N m'2 application so plots at the HF fertilizer level had, cumulatively, 30 g N 111'2 while plots at the LIF level and LF fertilizer level had, cumulatively, 20 g N m'2. However, plots fertilized at the LIF level had only 4 applications while plots at the LF had 7 and plots at the HF level had 6. The fact that all plots just had an equal amount of nitrogen applied coupled with the increased frequency of application of fertilizer for the LF plots may have caused the plants to become hardier and equally able to withstand traffic as the plots maintained at the HF fertilizer level. The reason this effect did not show for the rest of the season may have been because when the final cover ratings were taken, the effects of traffic simulation 56 were very severe. Therefore, the chances of variability between treatments had become greatly reduced. Surface Hardness Statistical significance occurred between surface hardness ratings on 01 October 2001 (51.8, 49.4, and 52.7) for the LIF, LF, and HF fertilizer levels respectively (Table 22). However, because the difference between ratings was so small (less the 5 Gmax), it is inconclusive whether fertilizer rate and frequency had an effect on surface hardness ratings. Shear Strength Statistical significance occurred between Eijelkamp shear vane ratings on 26 October 2001 (19.2, 17.6, and 17.8) for the LIF, LF, and HF fertilizer levels respectively (Table 23). However, because the difference between ratings was very small, it is inconclusive whether or not fertilizer rate and frequency had an effect on shear strength. Previous research has shown that for treatment effects to be truly significant, the difference between ratings should be greater then five (Stier and Rogers, 2001). Shear/clegg Plots fertilized at the LIF rate had higher shear/clegg ratings then plots fertilized at the HF rate on 25 August, 15 October, and 16 November 2001. Although the LIF rate of fertilizer had increased shear/clegg ratings for those 57 three sampling dates, the increase in shear strength was minimal (Table 24). However, a possible reason for the LIF fertilizer rate having higher shear strength ratings may be because of increased rooting and shoot growth (Bredakis and Roberts, 1959; Juska, 1967). In addition, the reason the shear/clegg ratings showed differences between fertilizer treatments and the shear vane did not could be because the shear/clegg measures lateral shear strength (plant displacement from the soil) while the shear vane measures rotational shear strength (plant and plant tillers). Quality Fertilizing at the HF rate gave a higher quality rating then fertilizing at either then LIF or the LF rate on 01 and 15 October. On 26 October and continuing through 09 November, the HF rate of fertilizer gave a higher quality rating then only the UP rate of fertilizer (Table 25). The reason plots fertilized at the HF level gave higher quality ratings then plots fertilized at either of the other levels from 01 through 15 October 2001 may be because the plants were getting more of the nutrients they needed when they needed them. In Michigan, October is typically the end of the optimal growing season for cool season turfgrasses. Therefore, any additional nutrients will improve turfgrass growing conditions- especially considering that these plants were being grown in a sand rootzone (Baker and Jung, 1968). As a result, plants receiving more fertilizer appeared to be healthier. Plots fertilized at the LF level got the nutrients at a slightly higher frequency, but the quantity per application was lower. This could have resulted 58 in the lower quality ratings. However, as traffic simulation continued, quality ratings for these plots were no different from quality ratings for plots fertilized at the HF level. This could be because fertilizing on a low, but frequent basis caused the plants to become hardier and better able to withstand traffic as time went continued. Color Fertilizing at the HF level gave higher color ratings then fertilizing at either the LIF or the LF level on 01 October through 26 October. This effect was seen because, at these ratings dates, plants fertilized at the HF level appeared to be getting more of the nutrients they needed when they needed them. As a result, these plants appeared to have more vibrant color. In Michigan, October is typically the end of the optimal growing season for cool season turfgrasses. Therefore, any additional nutrients will improve turfgrass growing conditions and cause the plants to appear healthier-especially considering that these plants were being grown in a sand rootzone (Baker and Jung, 1968). Plots fertilized at the LF level had lower color ratings the plots fertilized at the HF level because although they got the nutrients at a slightly higher frequency, but they got them at a lesser quantity. Plots fertilized at the LIF level had lower color ratings because although they received as much fertilizer per application as did plots at the HF level, the accumulated amount and frequency was lower. In addition, plots fertilized at the LF and HF level received fertilizer more frequently then plots 59 fertilized _at the LIF level. Hence, when color ratings were taken, these plots had usually just received a fertilizer application (Table 3 and 26). Cultivation Plant counts Cultivating had no effect on plant counts. Cultivation may not have had an effect on plant counts because the study was on a three-year old, sand based root zone field. Therefore, the field was probably not compacted enough to have differences in plant counts. In addition, cultivation was done at the end of traffic simulation and again in the early spring. Thus, when plant counts were taken, almost four months had passed since the plots had been cultivated. Therefore, any long-term cultivation benefits were not attained in terms of an increase in plant counts (Table 20). Turfgrass cover Although statistical significance occurred between turfgrass cover ratings on 01 October 2001 (52 and 56%), for the low and high cultivation frequencies respectively, the ratings did not differ enough to warrant discussion of cultivation effects on turfgrass cover. Because the ratings were qualitative, the effect only occurred once, and the variance did not show in plant counts (Table 20), the difference was probably incidental. However, more investigation is warranted because this data, although weak, does show the potential for cultivation 60 frequency to extend turfgrass cover for at least an additional 4 traffic applications (Table 21). Surface Hardness Plots not cultivated had higher surface hardness ratings then plots cultivated twice per year from August through 26 October 2001 (Table 22). This effect may have occurred because cultivation directly affects soil conditions; therefore it has the potential to greatly influence surface characteristics as it did August through 26 October 2001. This result was also seen on Poa pratensis and Festuca arundinacea in a study done by Rogers in 1990. These results show that surface hardness can be lowered by cultivating twice per year for an additional 36 passes. The reason this effect did not show for the rest of the traffic simulation may have been because when the final surface hardness ratings were taken, the effects of traffic simulation were very severe. Therefore, the chances of variability between treatments had become greatly reduced. Shear strength Statistical significance occurred between Eijelkamp shear vane ratings on 09 November 2001 (14.8 and 13.1) and 16 November 2001 (13.9 and 12.2), for the low and high cultivation frequencies, respectively. However, because the difference between the ratings was so small, it is inconclusive as to whether cultivation frequency had an effect on shear strength. Previous research has shown that for treatment effects to be truly significant, the difference between 61 ratings should be greater then five (Stier and Rogers, 2001). Furthermore, when these ratings were taken turfgrass cover and plant count ratings were very low (Table 20 and Table 21), therefore the differences for these dates is most likely due to chance by sampling location (Table 23). Shear/clegg Plots cultivated twice per year had higher shear/clegg ratings then plots not cultivated on 26 October 2001 and 09 November 2001 (Table 24). The reason for this effect may be because the higher cultivation frequency may have caused an increase in rooting due to increased macro pore space during this period of time (Lee and Rieke, 1993). Because the shear/clegg measures lateral shear strength, an increase in rooting would have given an increase in lateral shear strength. The reason this effect was reversed on 09 November 2001 for Eijelkamp shear vane ratings may be because the shear vane measures rotational shear strength as opposed to the lateral shear strength. Quality Although statistical significance between quality ratings occurred on, 15 October (3.7 and 4.2) and the 26 October 2001 (3.3 and 3.8), for the low and high cultivation frequencies respectively, the ratings did not differ enough to warrant discussion of cultivation effects on turfgrass quality. Because the ratings were qualitative, the difference was probably incidental. However, more investigation is warranted because this data, although weak, does show the 62 potential for cultivation frequency to extend turfgrass quality for an additional 4 traffic applications (Table 25). Color Cultivation did not have a visible effect on color ratings. Cultivation may not have a visible effect on color ratings because the study was on a three-year old, sand based root zone field. Therefore, the field was probably not compacted enough to warrant cultivation frequency having a significant affect on nutrient availability or nutrient holding capacity, either of which could have caused a difference in color ratings (Table 26). Mowing x Cultivation Interaction Plots mown twice per week had higher color, quality and plant count ratings if they were cultivated twice per week then if they were not cultivated. However, the difference between ratings was minimal and this was the only date that this effect occurred (Table 27). Mowing x Fertilization x Cultivation Interaction A three-way interaction occurred for turfgrass cover ratings on 01 October 2001. This interaction shows that cultivation by itself does not lead to increased turfgrass cover late in the season. However, cultivation does act as a catalyst for mowing and/or fertilizing applications to increase turfgrass cover. Thus, cultivation, in combination with either the low mow/HF fertilizer treatment or the 63 Table 27. Significance of the Interaction of mowing, cultivating and Cady traffic on turfgrass color1, quallty1, and plant counts’ on a Poe pratensis/Lolium perenne turf stand, East Lansing, MI. 2001 Color Quality Plant Counts (plants 1000m' 2) 10/01 10/15 11/12 10/15 Mowing x Cultivating Low mow Low cultivating 5.1 4.7 2.0 118.1 Low mow High cultivating 4.8 4.7 2.2 120.4 High mow Low cultivating 4.8 4.5 1.9 112.0 High mow High cultivating 5.6 5.2 2.7 138.4 1.60.0115) 0.7 0.5 0.4 17.0‘ # of Passes 20 30 44 30 1 Color was rated using the Spectrum” FieldScout chlorOphyll meter (Spectrum Technologies lnc., Plainfield, IL). 1 Quality was rated visually on a 1-9 scale: 1=necrotic turf/bare soil, 9=dense, uniform turf with acceptable color (color 2 5). 1 Plant counts were hand counted using three subsamples per treatment. 1 Significant to the 0.10 value. 64 high mow/LF or HF fertilizer treatment, did increase turfgrass cover. Furthermore, if both mowing and fertilizing are applied at the HF rate, there is not an increase in turfgrass cover. This is likely a result of the environmental and plant limitations. A three-way interaction also occurred for turfgrass cover ratings on 16 November 2001. On this date, it was shown that cultivation would increase turfgrass cover if plots were maintained at the low mowing and LIF fertilizer levels. If plots were maintained at either the high mowing frequency, or the LF or HF fertilizer level, cultivation would not increase turfgrass cover. Furthermore, cultivation increased plant counts if it was combined with either low mowing and LIF fertilizing or if it was combined with high mowing and HF fertilizing. A three-way interaction also occurred for various other ratings throughout the study. However, each of the observations were isolated, thus, no trend can be made (Table 28). Treatment Comparisons The highest and lowest level treatment regimes were compared to quantify the number of additional games gained from increased inputs. In addition, fertilizer regimes were compared to quantify the number of additional games gained from the varying fertilizer inputs (Appendix D). 65 dig mod 2: 0. Emowzcwfi : 3:238:93 N. 53> 13> N.E Z w mm H :3: 5:658:er w 55 18> N.E Z w mm H E33... 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Lao—3320 E; ammo—5:: coat—a mac—.3 :3... .3838 323...: .5 oEab menu 6:: “5.95.3 $53.23.. .9558 he 55228:. 2: he vacuum—.55 .3 «3:. 66 100 T—\ 80 ‘ 3 . \ 3 I g 60 1 +1x/week 5 40 T +2x/week . . “- 20 . _ 0 I Aug. 15 Oct. 01 Oct. 15 Oct. 29 Nov. 09 Nov. 16 Games Simulated 0 10 14 18 22 25 Figure 6. Effect of mowing and Cady traffic on turfgrass cover over time, East Lansing, MI, 2001 \ _ + Low Infrequent + Low Frequent + High Aug. 15 Oct. 01 Oct. 15 Oct. 29 Nov. 09 Nov. 16 Games Simulated 0 10 14 18 22 25 Figure 7. Effect of Fertilizer and Cady traffic on plant counts overtime, East Lansing, MI, 2001 67 Conclusions Sand soil The objectives of this study were ascertained, as we were able to quantitatively define differences between treatment applications. We are confident this research, coupled with continued research will set a foundation for which the future expectations of athletic fields based on cultural inputs of mowing, fertilizing, and cultivating can be determined. Mowing The object of this experiment was defined and it was determined that mowing twice per week versus once per week increased plant counts and turfgrass cover. Mowing twice per week also improved quality and cover ratings and on occasion, turfgrass shear strength and surface hardness characteristics. Fertilizing It was determined that when fertilizing with 25 g N rn‘2 year" frequent applications are best on a sand based root zone (at least 8 applications per year). In addition, less frequent fertilizer applications can be used if a greater amount of annual nitrogen is applied (35 g N rn‘2 year"). The higher annual nitrogen (35 g N rn'2 year") or the increased frequency of nitrogen application at the lower rate of nitrogen 25 g N rn'2 year" increased plant counts, percent cover, quality, and on occasion turfgrass shear strength 68 and surface hardness. Deciding between these two rates can be determined by environmental factors as well as labor and fertilizer costs. Cultivating Cultivating at the end of traffic simulation and again in the early spring provided increased turfgrass cover near the end of the experiment. Lower surface hardness values were obtained from core-cultivation throughout the study. In contrast, core cultivating showed a negative effect on turfgrass shear strength. 69 Chapter 2 Impact of Cultural Practices and Traffic on a Native Soil Athletic Field Introduction The combination of grass, maintenance, and condition of the root zone are essential components in determining if an athletic field will hold-up under game traffic, or if it will fail. The root zone is the source of nutrient and water for turfgrass growth and it provides for the stability of the grass plants by anchoring their roots (Beard, 1973). The grass provides the cover of the field as well as adds stability. Consequently, even if the field has the highest standards for root zone and turf cover, if it is not properly managed, worn areas will occur, resulting in a lack of stability and decreased playing surface conditions. Worn areas and instability have been shown not only to reduce the playability and aesthetics of the field but also to increase field-related injuries (Harper et al., 1984; Rogers et aL,1988) An athletic field must provide firm footing, adequate resiliency on impact, and resistance to tearing during play. It must also drain well and resist compaction from continues severe traffic (Turgeon, 1996). This statement describes a combination of the two most commonly used athletic field root zones today. It describes the resistance to compaction of a sand based root zone and it describes the firm surface of an “existing” or native soil root zone-which is higher in silt + clay then a sand based field. Because both of these root zones 70 represent the different types of root zones used in Michigan athletic fields and because both of these root zones have benefits for athletic traffic and may respond differently to treatments, this research was done on both types of root zones. The pore spacing in a native soil root zone is primarily the result of aggregation from the cohesive nature of clay (Foth, 1990). There are benefits of using a native soil root zone for athletic field construction. Not only can native soil fields be cheaper to construct because the existing soil is used, but also, the smaller pore spaces provide for increased stability as well as increased nutrient and water holding capacity. In addition, because clay has a high cation exchange capacity, native soils are more fertile then sand based root zones on a regular basis (Beard, 1973). Unfortunately, native soil fields have less desirable characteristics as well. The clay aggregates in a native soil can be destroyed by intense traffic, which causes a reduction in pore space. Smaller pore spaces leave the stand more susceptible to compaction, and subsequently, a decrease in drainage and a decrease in air and water flow (Adams and Jones, 1979). Eventually, a decrease in root and shoot growth will occur, leaving the plant much weaker (Beard, 1973; Lee and Rieke, 1993; Nelson and Larson, 1994). The native soil field was on existing Capac loam soil (Fine-loamy, mixed, mesic Aeric Ochradqualfs) with a poa pratensis blend cover. The maintenance practices for this research consisted of twelve different treatments, compromised of three treatment factors each; mowing, fertility, and cultivation. The mowing height (6 cm) was slightly higher then the mowing height chosen for the sand 71 based field. This height was chosen because it is the optimal mowing height for a non-irrigated, poa pratensis stand, subjected to high traffic conditions (Rogers, pers. comm.) The increased mowing height is necessary for a native soil, non- irrigated field receiving intense traffic because it should result in increased root and rhizome growth, which will increase resistance to drought stress (Turgeon, 1996) Fertilizer rate and frequency was slightly lower then the fertilizer rate and frequency for the sand based field. This is because of the increased nutrient holding capacity from the clay content. Fertilizer was applied at a rate of 5 g N m'2 two times per year for a total of 10 g N yr" (low infrequent), 2.5 g N m'2 applied 4 times per year for a total of 10 g of N yr"(low frequent), or 5 g N rn'2 applied 4 times per year for a total of 20 g N yr" (high). These rates and frequencies were chosen because this was a native soil based root zone-which has high nutrient holding capacity, we looked at the same annual rate of nitrogen with varying frequencies within the low rate of nitrogen to see if fertilizing less frequently would provide the same quality turf stand as fertilizing more frequently. This would mean that less labor would be needed to maintain the field, which is typical for a native soil field. Differences in nitrogen rates were looked at to see if the growth and development of the grass would differ at different rates when subjected to traffic. Similar to the sand based field, plots were cultivated zero or two times per year for the low and high rate, respectively. While the main reason for coring the sand based root zone field was to dilute the potential for layering from 72 decomposing organic matter, the primary reason for core cultivating the native root zone study was to alleviate compaction from trafficking as well as to dilute the effects of decomposing organic matter. With the results of this study we are going to quantify the relationship between cultural practices and turfgrass quality on a native soil athletic field. 73 Materials and Methods The experimental design for this study was a 2 x 3 x 2 (mowing x fertilizing x cultivating) randomized complete block design with three replications. Individual plots were 2.7 m by 2.7 m. Plots were located on an existing, non- irrigated, Capac loam soil (Fine-loamy, mixed, mesic Aeric Ochradqualfs) on the campus of Michigan State University. The area was seeded 27 August 1997 with Kentucky bluegrass var Conventry (Scotts Co., Marysville, OH) at a rate of 7.5 g m‘z. Plots were prepared for this research on 18 October 2000 by fertilizing with 5 g N m‘2 of Scotts 18-5-18 fertilizer (Scotts Co., Marysville, OH) and mowing to a height of 5 cm with a Toro zero turn mower (Toro 00., Minneapolis, MN). The only other maintenance procedure necessary was one spray application of Confront (lndianpolis, IN 33% triclopyr, 12.1% clopyralid, liquid formulation) on 8 May 2001 at a rate of .74 fl oz /1000ft'2 for control of broadleaf weeds. Plot maintenance Twelve different treatments, with three treatment factors each, (mowing, fertility, and cultivation) were used in this study. Plots were mown either once or twice per week for the low and high treatment, respectively. Fertilizer was applied at a rate of 5 g N In2 two times per year for a total of 10 g N m'2 yr" (low infrequent), 2.5 g N rn'2 applied 4 times per year for a total of 10 g of N rn'2 yr' 1(low frequent), or 5 g N rn'2 applied 4 times per year for a total of 20 g N m'2 yr" (high). Plots were core cultivated zero or two times per year for the low and high rate, respectively. These treatments are outlined in Table 29. 74 Table 29. Treatment applications for the native soll athletic field study, 2000, 2001. Treatment Mowing1 flimes/week") Fertilizer1 Q N rn’2 year") Cultivation? 1 1 10(LIF) NO 2 1 10(LIF) No 3 1 10(LF) Yes 4 1 20(LF) Yes 5 1 10(ngh) Yes 6 1 20(High) No 7 2 10(LIF) NO 8 2 10(LIF) Yes 9 2 10(LF) N0 10 2 10(LF) Yes 1 1 2 20(High) No 12 2 20(High) Yes 1' The native soll study was mown at 5 cm, respectively. 1 The fertilizer treatments consisted of low infrequent, lo1w frequent, and high levels. LIF- - 10 g N m 2'year 1with four applications; LF - 10 g N m 2'year 1with eight applications; High= 20 g N m 2year" with six applications. § Cultivation consisted of spring and fall core cultivation. 75 Mowing treatments began the first week of May 2001. All plots were mown to a height of 5 cm using a Tom zero turn mower (Toro Co., Minneapolis, MN) once per week. Plots mown at the high level were mown an additional time each week with a rotary mower set at 5 cm. Fertilizer treatments began for all plots on 18 October 2000. On 18 November 2000, a 10 g N m'2 of urea (46-0-0) dormant feeding was given to all plots. For 2001, Scotts 18-5-18 fertilizer (Scotts Co., Marysville, OH) was applied two or four times (Table 30). Fertilizer was applied with a drop spreader unless all plots were to receive at least 2.5 g of N m’z. In such cases, a rotary spreader was used to apply the 2.5 g of N rn'2 and a drop spreader was used to apply the additional 2.5 g of N m'z. Plots were cultivated 28 November 2000 and 9 May and 05 December 2001 using a 1.2 m Toro walking greens aerator with 7.6 x 0.64 cm tines (Toro C0., Minneapolis, MN). These plots were not irrigated, unless by nature. Traffic Simulation For traffic simulation, each 2.7 x 2.7 m plot was split in half; one half received traffic using the Brinkman Traffic Simulator (BTS) during late fall season 2000 and spring and fall seasons 2001, the other half received no traffic simulation. The BTS imposes both compactive and tearing forces on the turf by using full rollers with metal cleats. Two passes with the BTS equal the cleat marks between the hash marks and between the 40 yard lines during one NFL football game (Cockerham and Brinkman, 1990). For this research, 2 passes 76 Table 30. Annual fertilizer1 schedule for native soll athletic field study, 2000-2001. Year Date Low Medium High Infrequent Frequent --—------ gN rn'2 application" -------- 2000 18 October 5.0 5.0 5.0 18 November1 5.0 5.0 5.0 Total g N m'zlyr. 10.0 10.0 10.0 2001 3 May - 2.5 .. 22 May 5.0 2.5 5.0 12 June - 2.5 5.0 3 September 5.0 2.5 5.0 19 October - - 5.0 Total N m'2 10 10 20 T Scotts ProTurf fertilizer 18-5—18 1 Dormant fertilization using urea (460-0). 77 were made 2 times/week 23 October through 16 November 2000, 17 April through 24 May and 27 August through 19 November 2001. Data Collection Turfgrass density, color, quality, shear strength, and surface hardness ratings were made in October and November of 2000, and monthly from May through November of 2001. The density ratings were based on a visual percent cover scale (0-100%). Beginning in 2001, density was also measured quantitatively by plant counts 100 cm". Quality and color were rated on a visual (1-9) scale. For quality ratings, a rating of one was given for dead or no turf, six for acceptable turf, and nine for excellent turf. For color, a rating of one was given for yellow or brown turf, six for acceptable turf color, and nine for dark green. Beginning in July of 2001, color was assessed using the SpectrumTM FieldScout chlorophyll meter (Spectrum Technologies, lnc., Plainfield, IL). Shear strength was measured using an Eijelkamp shear vane (Eijkelkamp, Giesbeck, The Netherlands) and beginning in August of 2001, shear strength was also assessed using the Shear Clegg (Dr. Baden Clegg Pty Ltd., Perth, Australia) Surface hardness was measured using a Clegg Impact Hammer (Lafayette Instrument Co., Lafayette, IN). 78 Results and Discussion Results and discussion are divided by maintenance practice and then subdivided by the effect each practice had on the evaluation criteria. Interaction results and discussion are at the end. We designated surface hardness measurements between treatments to be inconclusive if differences were less then 5 gmax- A cost analysis for each treatment is also listed in Appendix C. Mowing Plant counts Plots mown twice per week gave a 31 % increase in plant counts over plots mown once per week in June and a 25 % increase over plots mown once per week in 01 October 2001 (Table 31). This effect was also seen on the sand based root zone. Once traffic simulation began, the root systems of the plants mown once per week may not have been as strong as the root systems of the plants mown twice per week, because all of their energy was being put towards shoot development. Therefore, when put under stress, these plants were removed from the ground much more easily causing a decrease in plant counts. The reason this effect only occurred on these two dates could be because the entire plot area was dormant, due to water and heat stress, throughout the month of July and part of August. Therefore, mowing and fertilizer treatments could not have much of an effect because the grass was not growing and the fertilizer could not be absorbed because of a lack of rain. Thus, although the grass was 79 Table 31. Significance of treatment effects and traffic on plant counts (plants 100cm )1, East Lansing, MI. 2000-01 5/08 6/15 7/12 8/25 10/01 10/15 10/29 11/09 11/16 Mowing 1x/week 35.3 128.0 88.7 75.5 68.1 67.1 73.6 76.4 67.8 2xlweek 39.0 185.4 97.5 81.9 91.4 78.7 71.5 84.5 70.0 Significance n5 ** ns ns “ ns ns ns ns Fertilization1 Low Infrequent 34.6 179.5 95.1 76.0 78.1 69.1 66.0 78.5 64.6 Lowfrequent 44.0 144.8 89.9 83.3 76.7 73.3 77.8 77.4 60.4 High 32.8 146.2 94.1 76.7 84.4 76.4 74.0 85.4 81.6 Significance n5 ns ns ns ns ns ns ns " Cultivation 0 x/yr" 39.7 181.7 97.9 85.7 87.3 75.7 70.6 81.3 73.4 2 x/yr" 34.6 131.9 88.2 71.8 72.2 70.1 74.5 79.6 64.4 Significance n5 * ns ns ns ns ns ns ns # of Passes 6 - - - 10 14 18 22 25 ', *" ,**‘ Significant at the 0.10, 0.05, and 0. 01 probability levels, respectively. Ns Not significant at the 0.10 probability level. :Plants were hand counted using three subsamples per treatment. 1Low infrequent- - 10 g N m 2'year 1with two applications; Low frequent - 10 g N m 2‘year 1with four applications; High= 20 g N m 2'year 1with four applications. 80 almost entirely out of summer dormancy by the time traffic simulation began, it is unclear how much of the treatments were able to have an effect on the plants. As a result, although this data implies that plots mown twice per week maintained higher plant count ratings for an additional two games, given the environmental factors, more research is warranted. Turfgrass cover Plots mown twice per week yielded at least a 4% increase in turfgrass cover over plots mown once per week on 15 October through 16 November 2001 (Table 32). This effect was only seen on these dates because in June, plant growth was fairly slow because growing conditions were not optimal and, in July and August plant growth was minimal because the plants were in summer dormancy. Therefore, mowing frequency effects on turfgrass cover really did not begin to show until turfgrass growth slowed and traffic simulation continued. At this time, the results indicate that mowing frequency has the potential to maintain increased turfgrass cover for a longer period of time under traffic simulation. This could be because the mowing at the proper height and frequency stimulates shoot growth and tillering (Juska, 1961; Crider, 1955). However, if more then 30% of the leaf blade of a plant is removed in a single mowing, all or nearly all of the plants energy goes into shoot production and negligible amounts, if any go into root, rhizome, or tiller initiation (Crider, 1955). The negative effect of the apparent weakened root system becomes obvious once traffic simulation begins because these plants are torn from the ground more easily, causing a decrease 81 Table 32. Significance of treatment effects and traffic on turfgrass cover', East Lansing, MI. 2000-01 2000 2001 10/27 5/15 6/15 7/12 8/25 9/13 10/01 10/15 10/26 11/09 11/16 Mowing 1x/week 100 51 57 20 35 38 34 35 37 35 18 2xlweek 100 54 61 18 31 38 36 41 45 43 22 Significance ns ns ns ns ns ns ns " “* "* " Fertilization1 Low infrequent 100 53 60 18 31 39 36 39 40 38 20 Low frequent 100 50 60 20 34 37 33 36 41 37 1 7 High . 100 55 58 19 34 38 36 39 43 41 24 ns t. Significance ns ns ns ns ns ns ns ns ns Cultivation 0 x/yr" 100 56 59 24 41 40 36 39 43 40 22 2 x/yr" 100 49 60 14 25 36 34 37 40 38 19 Significance n5 ' n5 *“ *“ " ns ns ns n5 n5 # of Passes - 6 - - - 5 10 14 18 22 25 ', “ ,*“ Significant at the 0.10, 0.05, and 0. 01 probability levels, respectively. Ns Not significant at the 0.10 probability level. :Turf cover was visually estimated on a percent (0-100%) scale. 1Low infrequent- -' 10 g N m2year1with two applications; Low frequent- '- 10 g N m2'year1with four applications; High= 20 g N m 2'year 1with four applications. 82 in visual density (Table 31). Hence, this data shows that mowing twice per week will result in higher turfgrass cover ratings for an additional ten games. Surface hardness Mowing frequency did not have an effect on surface hardness. This is likely because mowing effects plant physiology, not soil conditions (Table 33). Shear vane and Shear/clegg Plots mown twice per week gave higher shear strength ratings then plots mown once per week on 16 November 2001 (Table 34 and 35). This effect may have been seen because at the time of data collection, there was a significant difference in turfgrass cover (18 and 22%); thus yielding a significant difference in shear vane ratings (6.2 and 7.1) and shear/clegg ratings (17.0 and 20.1) for plots mown once per week versus plots mown twice per week. However, because the turfgrass cover in plots mown twice per week was only 4% greater then in plots mown once per week, getting an accurate rating with the Eijelkamp shear vane was nearly impossible. In addition, because this was the only date that mowing frequency had an effect on shear strength, the difference may have occurred as a result of chance by sampling location. Quality Plots mown twice per week gave higher quality ratings then plots mown once per week on 09 November 2001 (Table 36). This effect probably occurred 83 Table 33. Significance of treatment effects and traffic on surface hardness1, East Lansing, Ml.2000-01 2000 2001 10/27 5/15 6/15 7/12 8/25 9/13 10/01 10/15 10l26 11/09 11/16 Mowing 1xlweek 70.3 88.2 60.1 130.5 88.0 82.7 69.5 55.2 77.3 78.7 61.9 2xlweek 68.9 87.6 62.8 114.7 86.3 84.9 67.6 52.7 64.4 79.7 63.9 Significance ns ns ns ns ns ns ns ns ns n5 n5 Fertilization‘ Low infrequent 71.0 91.1 62.8 146.5 89.1 87.8 68.1 55.1 66.1 79.9 64.3 Lowfrequent 70.2 85.9 616 112.9 864 80.1 67.2 54.0 643 78.7 60.8 High 67.6 86.7 60.9 108.5 86.0 83.6 70.4 52.7 82.2 78.9 63.6 _gignificance ns ns ns ns ns “ ns ns ns ns ns Cultivation 0 x/yr" 68.6 87.4 61.8 122.7 92.8 89.7 71.6 55.1 79.6 81.7 64.0 2 x/yr" 70.6 88.4 61.8 122.5 81.5 77.9 65.5 52.8 62.0 76.6 61.8 Significance ns ns ns ns 1“ “" *” ns ns “ ns # of Passes - 6 - - - 5 10 14 18 22 25 ',",“* Significant at the 0.10, 0.05, and 0.01 probability levels, respectively. Ns Not significant at the 0.10 probability level. 1 Surface hardness was measured using the Clegg Impact Soil Tester in gravity deceleration (Gmax). 1 Low infrequent = 10 g N m'2 year" with two applications; Low frequent = 10 g N m'2 year" with four applications; High = 20 g N rn'2 year" with four applications. Table 34. Significance of treatment effects and traffic on turfgrass Eijelkamp shear strength1, East Lansing, MI. 2000-01 2000 2001 10/27 5/15 6/15 7/12 8/25 9/13 10/01 10/15 10l26 11/09 11/16 Mowing 1xlweek 30.9 19.6 22.2 20.6 15.3 16.0 14.9 15.6 15.3 10.9 6.2 2xlweek 31.0 19.0 22.1 20.4 15.5 17.3 16.1 15.6 15.6 10.8 7.1 figfificance n5 n5 ns ns ns ns ns ns ns ns m Fertilization1 Lowinfrequent 31.0 19.1 21.1 20.1 15.6 16.0 15.7 16.1 15.1 11.0 6.5 Lowfrequent 31.3 19.3 23.2 20.8 14.7 16.5 15.1 15.5 14.8 10.7 6.8 High 30.5 19.4 22.1 20.6 15.9 17.4 15.8 15.2 16.5 10.9 6.5 flgnificance n5 ns ns ns ns ns ns ns ns ns ns Cultivation 0 x/yr" 30.1 19.8 22.4 21.7 16.0 17.4 15.3 15.4 15.6 10.4 6.4 2 x/yr" 31.1 18.8 21.9 19.3 14.8 15.8 15.8 15.8 15.4 11.3 6.8 Significance ns ns ns “* ns *‘ ns ns ns ‘" ns # of Passes - 6 - - - 5 10 14 18 22 25 *,**,“* Significant at the 0.10, 0.05, and 0.01 probability levels, respectively. Ns Not significant at the 0.10 probability level. 1 Shear strength was measured using the Eijelkamp Shear vane in Newton meters (sz). 1 Low infrequent = 10 g N m'2 year" with two applications; Low frequent = 10 g N m’ year" with four applications; High = 20 g N m'2 year" with four applications. Table 35. Significance of treatment effects and traffic on turfgrass Clegg/shear strength1, East Lansing, MI. 2001. 9/13 10/01 10/15 10l26 11/09 11/16 Mowing 1xlweek 16.3 19.9 15.6 19.4 22.6 17.0 2xlweek 18.6 19.8 16.6 19.1 23.4 20.1 Significance ns ns ns ns Ns ** Fertilization1 Low infrequent 15.5 20.5 17.1 17.6 24.0 20.0 Low frequent 19.5 19.8 14.7 20.4 22.0 18.8 High 17.3 19.2 16.5 19.6 23.0 16.9 _S_ignificance ns ns ns ns ns ns Cultivation 0 x/yr"17.9 19.1 16.2 18.8 22.4 19.1 2 x/yr" 16.9 20.5 16.0 19.7 23.6 18.0 Significance ns ns ns ns ns ns # of Passes 5 10 14 18 22 25 ‘ ,“ ,“* Significant at the 0.10, 0. 05, and 0. 01 probability levels, respectively. Ns Not significant at the 0.10 probability level. 1 Shear strength was measured using the shear/clegg In Newton meters. 1Lowi2nfrequ16nt= 10 g N m 2year 1with two applications; Low frequent = 10 g N m 2'year 1with four applications; High= 20 g N m 2year 1with four applications. Table 36. Significance of treatment effects and traffic on turfgrass quality1, East Lansing, Ml. 2000-01 2000 2001 10/27 5/15 6/15 7/12 8/25 9/13 10l01 10/15 10/26 11l09 11/16 Mowing 1xlweek 7.5 6.7 7.0 1.3 5.0 3.7 2.9 3.4 4.0 3.6 3.6 2xlweek 7.5 6.7 7.1 1.5 5.2 3.8 2.8 3.5 4.3 4.1 3.8 flgnificance n5 n5 ns ns ns n5 ns ns ns “ ns Fertilization1 Low 7.5 6.7 7.1 1.4 5.1 3.7 2.9 3.5 4.3 3.8 3.6 infrequent Low frequent 7.5 6.7 7.0 1.5 5.3 3.8 2.6 3.3 3.9 3.6 3.3 High 7.5 6.8 7.0 1.4 5.0 3.8 3.0 3.6 4.2 4.1 4.2 _ggnificance n5 n5 ns ns ns ns ns ns ns ns 1'" Cultivation 0 x/yr" 7.5 6.8 7.0 1.7 5.2 3.9 3.1 3.6 4.2 4.0 3.8 2 x/yr17.5 6.6 7.1 1.1 5.0 3.6 2.6 3.3 4.0 3.7 3.5 Significance n5 n5 n5 " ns ns " ns ns ns ** # of Passes - 6 - - - 5 10 14 18 22 25 " ," ,“* Significant at the 0.10. 0.05, and 0. 01 probability levels, respectively. N5 Not significant at the 0.10 probability level. 1Quality was rated visually on a 1-9 scale: 1=necrotic turf/bare soil, 9: dense, uniform turf with acceptable color (color_ > 5).2 1Low infrequent - 10 g N m2year1with two applications, Low frequent - 10 g N m 2year 1with four applications; High= 20 g N m 2year 1with four applications. 85 because the increased mowing frequency caused the older leaf tissue to be removed and newer leaf tissue to emerge, as a result plants appeared to be more vibrant and healthy. In addition, plots mown twice per week were not put under “mowing stress.” Plots mown once per week were having more then 30% of their leaf tissue removed with each mowing. This may have caused less energy to go towards the root system and much more to go towards the shoots (Crider, 1955). When the plants were not under additional stress, the effects of this physiological change went unnoticed. However, when the plants were put under the additional stress of traffic, the effects become discemable. This resulted in less turfgrass cover (Table 32) in plots mown once per week, thereby causing individual plant damage (i.e. necrosis) to be less noticeable and the quality to appear lower. In addition, this effect appeared after traffic simulation began; thus, this data implies that mowing, in combination with traffic, stimulated higher wear tolerance and more growth, which resulted in greater turfgrass quality. However, because the plants were just recovering from drought and heat stress when time traffic simulation began, it is unclear how much of the treatments were able to have an effect on the plants. Color Plots mown twice per week had higher color ratings on 09 and 16 November 2001 then plots mown only once per week. This effect may have occurred as a result of increased mowing frequency, which caused the older leaf tissue to be removed and newer leaf tissue to emerge. This caused the plants to 86 appear healthier and more vibrant (Table 37). In addition, plots mown twice per week were not put under “mowing stress.” Plots mown once per week were having more then 30% of their leaf tissue removed with each mowing. This may have caused less energy to go towards the root system and much more to go towards the shoots (Crider, 1955). When the plants were not under additional stress, the effects of this physiological change went unnoticed. However, when the plants were put under the additional stress of traffic, the effects became discemable. This resulted greater turfgrass cover (Table 32) in plots mown twice per week, thereby causing individual plant damage (i.e. necrosis) to be less noticeable and the color to appear darker. Fertilization Plant counts and Turfgrass cover Fertilizer rate and frequency had an effect on plant counts and turfgrass cover ratings on 16 November 2001 when the high (HF) rate of fertilizer yielded at least a 21% increase in plant counts and at least a 4 % increase in turfgrass cover over plots fertilized at either the LIF (LIF) or the low frequent (LF) rate (Tables 31 and 32). This effect was seen because, within one month of this rating date, plots fertilized at the HF level were the only plots to receive a fertilizer application. Plots maintained at either of the other two levels did not have a fertilizer application since 3 September 2001. Because the plants in these regimes were most likely low in nitrogen, they did not recuperate or generate growth as rapidly, therefore they had a lower number of plant counts (Kussow, 87 Table 37. Significance of treatment effects and traffic on turfgrass color1, East Lansing, MI. 2000-01 2000 2001 10/27 5/15 6/15 7/12 8/25 9/13 10/01 10/15 10/26 11/09 11/16 Mowing 1xlweek 7.0 8.0 8.5 3.3 6.4 5.0 5.5 6.0 6.5 4.8 4.3 2xlweek 7.0 8.0 8.5 3.4 6.5 5.2 5.7 6.4 7.1 5.2 4.7 Sign nificance ns n5 n5 ns ns ns ns ns ns " " Fertilizationf Lowinfrequent 7.0 8.0 8.5 3.3 6.2 5.1 5.3 6.2 7.0 4.8 4.3 Lowfrequent 7.0 8.0 8.5 3.3 7.0 5.1 5.5 6.1 6.7 4.8 4.3 High 7.0 8.0 8.5 3.5 6.3 5.1 6.0 6.4 6.8 5.4 4.9 _S'Ignificance ns ns ns ns ns ns ns ns ns “ “ Cultivation 0 x/yr" 7.0 8.0 8.5 3.6 6.7 5.2 5.7 6.3 6.8 5.0 4.6 2 x/yr" 7.0 8.0 8.5 3.1 6.3 5.0 5.5 6.2 6.8 5.0 4.4 Significance ns n5 n5 1'“ ns ' ns ns n5 n5 n5 # of Passes - 6 - - - 5 10 14 18 22 25 ‘, “ ,'“ Significant at the 0.10, 0. 05, and 0 01 probability levels, respectively. N5 Not significant at the 0.10 probability level. 1 October 2000 through June 2001 color was rated visually on a 1-9 scale: 1 = dead/no turf, 9" - uniform dark green turf. July through November 2001 color was rated using the Spectme FieldScout chlorophyll meter (Spectrum Technologies, lnc., Plainfield, IL). 1Low infrequent = 10 g N m 2year 1with two applications; Low frequent- - 10 g N m2year1with four applications, High= 20 g N m2year1with four applications. 88 2000 and Carrow et al., 2001). Fertilizer level may not have had an effect on plant counts at any of the other dates because the actual rates of annual nitrogen applied were in the range of what is recommended for Poa pratensis on a native soil root zone. Therefore, differences were less likely to occur. In addition, differences may not have shown in the summer months because there was very little water to dissolve the fertilizer for plant uptake (Appendix B). Surface hardness Fertilizer rate and frequency did not have an effect on surface hardness ratings except in September when the LIF rate of fertilizer gave a higher surface hardness rating then the LF rate of fertilizer (Table 33). Fertilizer rate and frequency may have had an effect on this date because the higher or more frequent nitrogen applications caused a greater accumulation of thatch; thus yielding significant differences in surface hardness. The reason this effect did not continue might be because the effects of continued traffic eliminated further differences in thatch accumulation. However, because no thatch measurements were collected, this is only a speculation as to why significant differences occurred on this date. Shear vane and Shear/clegg Fertilizer rate and frequency did not have an effect on turfgrass shear strength or shear/clegg ratings (Tables 34 and 35). Fertilizer rate and frequency may not have effect shear ratings because from June through August, plants only 89 get 6.5 inches of rain. Because this was the only water these plants received, absorption of fertilizer was probably very minimal. Therefore, fertilizer regime may have not had an effect on shear strength because plants were unable to absorb enough fertilizer to effect on tensile strength. Quality Fertilizer rate and frequency did not have an effect on turfgrass quality except on 16 November when the HF rate of fertilizer gave a higher quality rating then either of the other two treatments (Table 36). This effect was seen because, within one month of this rating date, plots fertilized at the HF level were the only plots to receive a fertilizer application. Plots maintained at either of the other two levels did not have a fertilizer application since 3 September 2001. Because the plants in these regimes were most likely low on nitrogen, they did generate growth or recuperate from traffic as rapidly, therefore the plants did not appear to be as healthy and the quality ratings were lower (Carrow et al., 2001). Fertilizer level may not have had an effect on plant counts at any of the other dates because the actual rates of annual nitrogen applied were in the range of what is recommended for Poa pratensis on a native soil root zone. Therefore, differences were less likely to occur. In addition, differences may not have shown in the summer months because there was very little water to dissolve the fertilizer for plant uptake (Appendix B). In addition, similar to other results from this study, because the plants were just recovering from drought and heat stress when time traffic simulation 90 began, it is unclear how much of the treatments, particularly mowing and fertilizing, were able to have an effect on the plants. As a result, although this data implies that plots fertilized at the HF level maintained higher turfgrass quality ratings for an additional two games, given the environmental factors, more research is warranted. Color Plots fertilized had the HF rate of fertilizer had higher color ratings then plots fertilized at either of the other two levels on 09 and 16 November as well (Table 37). This effect was seen because, within one month of this rating date, plots fertilized at the HF level were the only plots to receive a fertilizer application. Plots maintained at either of the other two levels did not have a fertilizer application since 3 September 2001. Because the plants in these regimes were most likely low in nitrogen, the color appeared lighter and less vibrant (Carrow et al., 2001). In addition, plant counts and percent cover ratings were higher in plots mown twice per week, (Table 31) causing more plants per unit area. This resulted in individual plant damage (i.e. necrosis) to be less noticeable and the color to appear darker for plots receiving the HF level of nitrogen. Fertilizer effects may not have been seen earlier in the season because there was no water to dissolve the fertilizer for plant uptake (Appendix B). Cultivation 91 Plant counts and Turfgrass cover It can be ascertained that cultivating had a negative effect on plant counts and percent turfgrass cover (Tables 31 and 32). This may be because the effects of cultivating, although intended to be beneficial, may have actually been detrimental. Because plots were not irrigated the aerification holes allowed the soil to dry out faster. This added an additional stress to the turf, which possibly caused a reduction in plant counts and turfgrass cover. Surface hardness Cultivation frequency had an effect on surface hardness ratings in August through 01 October 2001 and again on 09 November 2001 when plots not cultivated yielded higher surface hardness ratings then plots cultivated twice per year (Table 33). This result was also seen on Poa pratensis and Festuca arundinacea in a study done by Rogers in 1990. This effect was probably seen because cultivation directly affects soil conditions, therefore it has the potential to greatly influence surface characteristics, as it did in August through 01 October and again on 09 November 2001. Although surface hardness ratings were not significantly lower for plots cultivated twice per year on 15 and 26 October, the ratings on these dates continued with the trend that surface hardness ratings are lower on cultivated versus non-cultivated plots. Therefore, it can be determined that cultivation, done twice per year on a native soil root zone, decreases surface hardness for at least an additional 13 games. By 16 November cultivation frequency may have not had an effect on surface hardness because when the 92 final surface hardness ratings were taken, the effects of traffic simulation were severe. Therefore, the chances of variability between treatments had become reduced. Shearvane Statistical significance occurred between the shear vane ratings in July (21.7 and 19.3), September (17.4 and 15.8) and 09 November (10.4 and 11.4), for the low and high cultivation frequencies respectively. However, because the difference between ratings was so small, it is inconclusive as to whether or not cultivation frequency had an effect on shear vane ratings. Previous research has shown that for treatment effects to be truly significant, the difference between ratings should be at greater than five (Stier, 2001). Furthermore, when these ratings were taken turfgrass cover and plant count ratings were very low (Table 31 and Table 32), therefore the differences for these dates is most likely due to chance by sampling location (Table 34). Shear clegg Cultivation rate and frequency had no effect on shear/clegg ratings. Cultivation did not have an effect on shear/clegg ratings because the field was probably not compacted enough to show differences in shear/clegg ratings. The rooting amount and depth between plants probably did not differ enough to effect lateral shear ratings. Therefore, any long-term cultivation benefits were not attained for an increase in shear/clegg (Table 35). 93 Quality Although statistical significance occurred between quality ratings for July (1.1 and 1.7), 01 October (3.1 and 2.6), and 16 November ratings (3.8 and 3.5), for the low and high cultivation frequencies respectively, the ratings did not differ enough to warrant discussion of cultivation effects on turfgrass quality (Table 36). Because the ratings were qualitative, and the actual ratings between treatments differed by less then one, the statistical difference that showed for quality ratings was likely incidental. Color Although statistical significance occurred between color ratings in July (3.6 and 3.1), and September (5.2 and 5.0), for the low and high cultivation frequencies respectively, the ratings did not differ enough to warrant discussion of cultivation effects on turfgrass color (Table 37). Because the ratings were qualitative, and the actual ratings between treatments differed by less then 0.5, the statistical difference that showed for color ratings was likely incidental. Mowing x Fertilization Interaction Plots fertilized at the LIF level had greater turfgrass cover if they were mown twice per week. However, if plots were mown once per week, then turfgrass cover and plant counts were greater if plots were fertilized at the HF level (for the 10/29 rating date plots fertilized at the LF rate also yielded higher 94 turfgrass cover ratings). An interaction also occurred for shear vane and shear/clegg ratings. However, the differences between the ratings was minimal and each of the observations were isolated, thus, no trend could be drawn (Table 38). Fertilization x Cultivation Interaction Plots fertilized at the HF level had higher turf cover ratings if they were not cultivated then if they were cultivated both prior to and during traffic simulation. In addition, in May, plots fertilized at the HF level yielded higher surface hardness ratings if they were cultivated then if they were not. This effect was changed in late summer when plots fertilized at either the LIF or the LF level had lower surface hardness ratings if they were cultivated twice per year then if they were not cultivated. An interaction also occurred for quality and shear vane ratings. However, the differences between the ratings was minimal and each of the observations were isolated, thus, no trend could be drawn (Table 39). Mowing x Fertilization x Cultivation Interaction Cultivation increased quality and turfgrass cover ratings if plots were mown once per week and fertilized at the HF level. Cultivation also increased quality ratings if plots were mown twice per week and fertilized at the LIF level. This interaction shows that cultivation by itself does not lead to increased turfgrass quality or cover. 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S. 600 v.0 0.0 0.0 26.. .E0360.. 26.. 0.00 0.00 0.0. 0.00 5.00 0.00 0.0 0.0 o... 2.0.. ..:0360..:. 26.. 05.9.60 x . 50...... 0 :0 0:0 0:0 0 :0 005. 0 :0 NE: 00.0. 020 .30. 000:0.0... 000.50 .EZ. 0:0> .00:0 .060 ..3.r >.._03G PGON J: .OpngNA «Gnu .rmmGC—Efiz Goat—aw UCG ..:.0:0..0 .00:0 09:00:05 ...0>00 {£330 «00.0.5. :0 050.. 0:0 0:202:30 .0:.N.....0. .0 :0..00.0.:. 0:. .0 00:00:60.0 .00 0.00.0 97 cultivation, in combination with either the low mow/HF fertilizer treatment or the high mow/LF or HF fertilizer treatment, did increase turfgrass quality and cover. Furthermore, if both mowing and fertilizing are applied at the HF rate, there is not an increase in turfgrass quality or cover. This is likely a result of the environmental and plant limitations. Conversely, if plots were mown twice per week and fertilized at the LF level, cultivation decreased turfgrass cover. However, this was an isolated finding so the actual significance is inconclusive. A three-way interaction also occurred for plant count ratings. Plots maintained at low mow and LIF fertilizer had lower plant counts if they were cultivated then if they were not. However, again this was an isolated finding so the actual significance is inconclusive (Table 40). * The Spring traffic applications did not yield any significant differences probably because treatments had not been applied for a long enough period of time. 98 .20. 0o... 0... .0 €80.60 0 0.6002300 .30. 5.2. 7.00.. N..... z 0 cm H :0... 0:38.600 .30. :..2. ..00.. N.:. z 0 o. n .:0360.. 26.. .0:0..00..000 02.. :..2. 7.00.. A...E z 0 o. n .:0300..:. 2.0.. — .E0E.00.. .00 00.00.0830 00.:. 0:.03 00.:300 0:0: 0.02. 0E0... 0 0.000 300070. E0800 0 :0 00.0E..00 >_.030.> 002. .060 03... . .3 M .060. .0.00 0.00.0080 :..2. ..3. E.0..:3 .00:00u0 ._.00 0.0.2.5. 26.00:". 0.000 0-. 0 :0 2.0303 00.0. 002. £030 _ ..0.3” 0.0. 0.0. 0... .. 00.. .00 0.00 0.0.. 0.. :0... :0... .835 0.8. 0.00 0.00 0.. 26.. :0... 000250 0.... .00 0.0.. N. .0... ....0=8..33 .0035 0.3. .00 0.00 2. 33 €030.33 000250 0.00. 0.... 0.00 0.. .0... ....0=8.....33 000250 0.00 0.00 0.00 0.0 33 ....0=..0....:so._ .835 0.00. 0.0.. .00 0.0 .00.: :9: 0002.3 0.0 .00 2.. 0.. 26.. .00.: :82... 0.8 0.2 0.00 N. .0... .5823... 00033 0.... .00 0.0.. 0.. 33 .508... 33 2002.3 0.00 .00 0.0.. 0.. .0... ....0=..0...._;o._ .6033 0.0: :0 .02 0.. 2.3 .8392}... £833 £02.30 0.1.0.50. x 526.2 0:. 0:0 0:0 0:. 0E0.& 0.:300E0... .060 030 2:030 .80 ...2 0505.. .000 .00.:300 E0... 0:0 0.0.60 .3506 0006.5. :0 00.0.. 0:0 0:002:30 0:356. 0526.: .0 :0..00.0.:. 0:. .0 00:00:60.0 .3 0.00... 99 Conclusions Native soil The objectives of this study were ascertained, as we were able to quantitatively define differences between treatment applications. We are confident that this research, coupled with continued research will set a foundation for which the future expectations of athletic fields based on cultural inputs of mowing, fertilizing, and cultivating can be determined. However, due to drought, the turf was in summer dormancy through much of the experiment. This may have caused the effects of the treatments to be lessened. Mowing The object of this experiment was defined and it was determined that mowing twice per week was generally better then mowing once per week. Although not always significant, mowing twice per week increased plant counts. Unlike the sand soil study, differences between mowing treatments were not as evident in terms of other data collection measurements. This is likely because the mowing treatments were not in place long enough (October 2000 - November 2001) to produce a significant effect. Fertilizing It was determined that fertilizing did not produce significant trends for any of the data collected. 100 Cultivating Core cultivating had a negative effect on turfgrass cover and shear vane ratings. This negative effect was likely a result of the core aerification holes remaining open during the hot and dry summer months and the lack of irrigation. Conversely, cultivation did decrease surface hardness ratings during traffic simulation as anticipated in a native soil root zone. 101 APPENDICES 102 .20: .50» .0 2.05035:— u:. 95:00:00 Eaten—E. o: »uE .00. 30» .05 .50.. 2:. .0 :00: u... 0. anuEES 7:00.00- »:0 000 0000....— ...u50 .0 w:_=30.:0> .m 520...; .0 9.002000... .m 5:00:02. 0:: 0=0w .N 30:00:50. 5:03:30 0.00 ._ 0.3000 .05 :0 0.2.0 0000.... 003 30» 00 00050:. 500.530 .055 2:00.000. A320... .30» 0.03.30 30» 00 :0:>> 0.0.20... .30» 0.03.30 30» OD 0.00. 00002. 5.2. 00.0.50 0. 30.0... .30»..0 03.50.00 0:3 . 3...... 30» 00 00:0 2.0: CH. .. 3:00 30» 00 020... 5.22. 0 00.0“» .05. 000.058: 3.50 30.4 00 00:0 30 0000.053: 3.30 30» 00 020... :02? 0 . 0300» .05 80.0.33. 30:0 30» 00 5:0 2.0 _ 0000.0_w:3.. 3.30 30» 00 020... :0.:2. 0 . 0900» .05 0000.020 30» 00 0.0. .055 .0. 00.00» .0... 0000.020 30» 00 5:0 30: 00». 0000 3.00% 05.2. 080.03 30» 00 0:3 0080.020 30» 0. 30.0... :02? 09.00.02 BESS .02. 3.50 30» 00 :owo...: :03:. 30: ill. .500» .05 SEES. 3.50 30» 0 0 5:: 2.0: .0005. 8.. 00 E .2. 5...... .20.... .5. 8 0 0.00 .022. 0:0...0ME. 0..0E0.30 020: 30» 0.10.0.0. :02... .0... 0.00:2. :6 A520... .30» 30E :0» 00.: 0: 3:2. 2 00.002. .0... «0.20... .30» 30:. 30» 00 5:0 25— . 2002. .2. 3.0.0... .30» :0 00E0w 0.0: 30» 00 5:0 25: 00.003 .00 $0.0... .30» :0 00:00.: 30» 00 00:0 2.0: ”3.0000 .050 0.0... 00000... 050.50 5:003:80 0.0... oEuw 0:350 5:003:80 0.0... 00:00... .308 20... 080w .800w 0.0... 00:00.... :38...— 0_0_.. 0.5% .0500... 02 00> 02 00> .03... s 0» 0. 3.50 .05 05.0030 0:. .0305 0000.: 600000 m:_30=0. 05 .0...— 030» 0. E00 00:05.02. 020.2205 0:50 8.: 30» 0.302. 0: .: 02205 :0..0.0000< 0.02.5.2 0.3.0 000% 0.00:0: 0:. 0. w:0_u: 30» on. l 030» o. .000 :0..0::o..:. 020.2255 058 0.... 30» 0.302. 0: .= 022.092. :0..0.0000< 0.09.5.2 ...3.—. 008m 59:22 0:. 0. m:0_o: 30» on a 03:000....0E 0.0... 000.50 .0. 0.08:0 30:00 .30» 0000 w:.0:3.. .0350 :03... 2.0: »0>.:.m .0055 :3: :0u.:0_2 < 20:250. 5:082 .30 c. 03 0.0 0. 00 00 o.o_._E00 0. 30» 8.: 0.303 02. 3.2.30 0 0. 320m 00.0... 000.50 30:00 :9: .0 03:00:. .EEomEuE $50.03. »03.0 0 9:830:00 3.02.50 0. 3.0.03.5 0.8m :0m.:0.2 .0 E030... .:qum0:02 t3... 008w 0:... ._v 030... .5230. 0:3: 30:8 .2050 103 Michigan High School Survey Results Table 42. Results for Football Games fields from the Michigan High School Survey, 1999-2001. Mowing Responses (Am. or %) Average Height 2.5” How often do you mow your field? 1xlweek or less 39% 2X/W88k 300/0 2xlweek or greater 12% Fertilizing Average frequengy of Application 3.3 ajpsjyr. Do you Fertilize you Field Yes 96% NO 4% How much fertilizer do you put down (per app.) ? Did not know 83% 1 lb. or less 5% 2 lbs. 1% 3 lbs. or ggater 7% Cultivating Do you cultivate your field? Yes 65% NO 350/0 lrrigating Is your field Irrigated? Yes 96% NO 4°/o 104 APPENDIX B Rainfall Table 2000-01 Table 43. Temperature and Rainfall for Hancock Turfgrass Center, 2000-01 Date Daily TemperatureC’F) 2000 Low High Average Rainfall Game played Aug. 24 63 82 72 0.0 X Aug. 25 55 80 69 0.0 Aug. 26 59 82 70 0.0 Aug. 27 62 80 71 0.0 Aug. 28 64 79 73 0.0 X Aug. 29 64 81 74 0.0 Aug. 30 64 83 74 0.0 Aug. 31 64 83 76 0.0 X Sept. 1 64 88 77 0.0 Sept. 2 65 90 74 0.0 Sept. 3 65 82 74 0.0 Sept. 4 58 82 63 0.0 X Sept. 5 46 68 57 0.0 Sept. 6 44 67 60 0.0 Sept. 7 48 75 66 0.0 X Sept. 8 54 83 66 0.05 Sept. 9 54 78 68 0.40 Sept. 10 68 82 77 1.4 Sept. 11 65 86 71 0.05 X Sept. 12 63 77 69 0.03 Sept. 13 45 74 60 0.04 Sept. 14 47 74 56 0.89 X Sept. 15 47 65 55 0.01 Sept. 16 41 63 52 0.0 Sept. 17 44 63 59 0.0 Sept. 18 44 74 62 0.0 X Sept. 19 48 79 66 0.0 Sept. 20 62 83 67 0.51 Sept. 21 46 71 52 0.0 X Sept. 22 40 57 52 1.94 Sept. 23 43 64 58 0.02 Sept. 24 47 72 52 0.00 Sept. 25 39 57 47 0.0 X Sept. 26 37 54 51 0.0 Sept. 27 38 65 54 0.0 Sept. 28 35 70 48 0.0 X Sept. 29 36 60 53 0.0 Sept. 30 41 70 58 0.0 105 Oct. Oct. 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(”NODU‘l-hwk) 9 11 12 13 14 15 41 60 52 49 46 46 32 32 35 36 38 36 39 51 49 46 42 39 49 50 42 44 52 55 55 58 42 28 28 30 32 45 41 36 33 36 39 42 43 43 39 38 40 32 30 75 77 78 71 66 55 51 49 52 62 68 71 77 75 68 57 63 68 71 73 75 69 66 65 67 74 73 51 57 62 66 68 70 60 53 60 58 51 58 62 49 45 43 49 43 59 69 62 58 51 49 41 38 49 53 58 65 60 53 55 55 55 61 63 56 55 59 61 65 66 47 43 45 48 50 58 51 45 47 47 45 50 53 46 42 41 45 38 34 0.0 0.0 0.0 0.0 0.81 0.0 0.21 0.07 0.05 0.0 0.0 0.0 0.0 0.02 0.0 0.23 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.80 0.05 0.0 0.20 0.11 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.12 0.0 0.09 0.64 0.0 0.0 0.0 0.0 0.81 106 Aug. 27 Aug. 28 Aug. 29 Aug. 30 Aug. 31 Sept. 1 Sept. 2 Sept. 3 Sept. 4 Sept. 5 Sept. 6 Sept. 7 Sept. 8 Sept. 9 Sept. 10 Sept. 11 Sept. 12 Sept. 13 Sept. 14 Sept. 15 Sept. 16 Sept. 17 Sept. 18 Sept. 19 Sept. 20 Sept. 21 Sept. 22 Sept. 23 Sept. 24 Sept. 25 Sept. 26 Sept. 27 Sept. 28 Sept. 29 Sept. 30 Oct. 1 Oct. 2 Oct. 3 Oct. 4 Oct. 5 Oct. 6 Oct. 7 Oct. 8 Oct. 9 Oct. 10 57.9 60.1 52.8 57.9 57.5 47.6 46.8 56.5 56.3 47.8 49.5 64.5 67.3 62.3 56.4 51.3 55.3 49.8 43.0 44.1 43.1 46.1 53.8 59.4 56.5 53.9 50.3 53.0 44.4 39.7 41.2 46.2 48.6 43.1 38.8 47.9 46.8 60.3 49.0 44.4 37.9 30.1 28.7 46.0 52.5 83.3 78.8 80.3 85.2 77.4 72.1 77.7 82.4 74.5 76.2 81.0 87.6 84.1 78.3 73.7 75.3 79.3 69.0 63.5 66.1 71.8 71.9 72.3 68.7 66.3 67.4 70.9 72.1 59.8 44.6 50.8 46.8 60.4 66.7 70.8 71.9 75.8 78.9 64.0 51.1 46.7 49.4 57.9 70.4 65.8 71 70 67 72 68 60 63 70 66 62 65 76 76 70 65 63 67 59 53 55 56 59 63 61 61 61 63 52 42 46 47 55 60 55 60 61 70 57 48 42 40 43 58 59 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.9 0.3 0.2 0.0 0.0 0.1 0.0 0.0 0.0 0.0 0.0 0.9 0.2 0.5 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.18 0.2 0.0 0.0 0.0 0.0 107 Oct. 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N5 .5 33 .5 .32.. 33 3.2 c. .62 .O .50 .N .50 .. .50 .O 5. .. ....< .5 2.3 .23. .Som ..u>0o Sammie .50.... :0 .88.... 5.23:... 0...... :aExctm 0:... .5852... .09. 2an 112 APPENDIX D COMPARISON OF THE EFFECT OF WEAR BETWEEN TREATMENTS 100 4. fi\ - ‘i——-I>\‘ . - 80 N ‘ , \4.\_\ Acceptable Turf cover } ‘ ........ .. -._. \\ 601”w “-\\ --.o--mm.mmm.m-mm. .0 i f ' ' +Hunuu mum Mignon l ...... O 20 % 0 A915 8013 cm ous om M09 M16 0 7 10 14 18 22 25 Games Simulated Figure 8. Comparison of Turf Density between Treatments under Brinkman Traffic. 2001 :- : ‘.‘\\ _ ' ' ‘Acoeptable Turf cover 0 . o 60 1 ~‘ - - O - ~Low Mow. Low lnfreq. Fort. Low 'F ' - Cult. 3 . . 2;. 4o ‘; b. . _ _ +High Mow High Fert. High Cult. ¢—..—-—..—'....____——. —_. L~‘-.:...__——. ._....... -- g | . _ . . ‘I\ o ‘ -.. \ °- 20 F ‘ ~ . . ‘t— . '0 ...... . o Aug. 13 Oct. 01 Oct. 15 Oct. 26 Nov. 09 Nov. 16 0 10 14 18 22 25 Games Simulated Figure 9. Comparison of Turf Density between Treatments under Cady Traffic, 2001 ' "v. . 4. . . , Acceptable Tun cover 80 - .Lfih‘V-‘Trrfi' 353-5. ' .. g wL ..,.‘.*.~:g“'. . .......Lowh"”mn[ i-——-——- —-—-——— — ---——- —-————- . -—-— 4-51- .. .,_--. —-I—Low Frequent 40 f ' - ...w.— ‘ .“ E . .,.,_ . . _‘ .9. 20 f o A A915 $0.13 or 01 ous 0.26 woe m 16 0 7 10 14 18 22 25 Games Simulated Figure 10. Turf Density as Effected by Fertilizer and Brinkman Traffic (Mown 1xlweek) ~L‘.,\ g m II “"I;'“~-O—_... 07:}: ‘: Wanda»- U ‘i .‘ "\‘.A .....Lm|mm .5 w i ' ‘ ~-e— Laura-qua: E w ~ ‘9 “on 20 ; o i__ A415 3913 Ol01 01.15 0:25 in 09 m 16 O 7 10 14 18 22 25 Games Simulated Figure 11. Turf Density as Effected by Fertilizer and Brinkman Traffic (Mown 2xlweek), 2001 113 \ Acceptable Turl cove ‘ \ .‘\ g 50 ; f\ - - O - -Low Infrequent ‘E E ‘. DB +Lo~v Frequent g 49 ‘6- . . \\ H'gh ' . ' ‘ '0. . 20 4 ~ . _ M ' . ''''' o ------- i‘ o 1_ Aug. 13 Oct. 01 Oct. 15 Oct. 26 Nov. 09 Nov 16 0 10 14 18 22 25 Games Simulated Figure 12. Turf Density as Effected by Fertilizer and Cadv Traffic (Mown 1xlweek) 100 -——Is .0 ‘ E; ”_W Turnover é a \ ‘ - - O - -mw ,_ N +Loulnqm E ‘° \ ‘ m.“ 2° 1 . . - . -‘\ 0 Aug. 13 Oct 01 Oct. 15 can Nov.” Nov. 10 0 7 10 14 18 22 25 Games Simulated Figure 13. Turf Density as Effected by Fertilizer and Cadv Traffic (Mown 2xlweek) 114 BIBLIOGRAPHY 115 Bibliography Adams, W.A., C. Tanavud, and CT. Springsguth. 1985. Factors influencing the stability of sportsturf rootzones. Proceedings of the International Turfgrass Research Conference. 5: 391-398. Adams, WA. 1981. Soil and plant nutrition for sports turf: Perspective and prospects. Proceedings of the International Turfgrass Research Conference. 4: 167-179. Adams, W. A. and R. L. Jones 1979. The effect of particle size composition and root binding on the resistance to shear of sportsturf surfaces. Rasen, Grunflachen, Begrunungen. 10(2): 48-53. Adams, W. A. 1976. The effect of fine soil fractions on the hydraulic conductivity of compacted sand/soil mixes used for sportsturf rootzones. Rasen, Grunflachen, Begrunungen. 7(4): 92-94. Anonymous. 2002. Mow and Prosper. Landscape Management. 2(41): 72. Baker, BS, and GA. Jung. 1968. Effect of environmental conditions on the growth of four perennial grasses. l Response to controlled temperature. Agronomy J. 60: 155-158. Beard, J.B., 1973. Turfgrass Science and Culture. Englewood Cliffs, NJ: Prentice Hall, Inc. Bingaman, D. E. and H. Kohnke 1970. Evaluating sands for athletic turf. Agron. J. 62: 464-467. Blake, GR. 1980. Proposed standards and specifications for quality of sand for sand-soiI-peat mixes. Proc. Int. Turfgrass Res. Conf. 3: 195-203. Bredakis, E.J., and EC. Roberts. 1959. The response of turfgrass roots to clipping and fertilization practices. 1959. Agronomy Abstracts. p. 88. Brown, K. W. and R. L. Duble. 1975. Physical characteristics of soil mixtures used for golf green construction. Agron. J. 67: 647-652. Canaway, P.M., M.J. Bell, G. Holmes, and SW. Baker. 1990. Standards for the Playing Quality of Natural Turf Association Football. Natural and Artificial Playing Fields: Characteristics and Safety Features. ASTM STP 1073. RC. Schmidt, E.F. Hoemer, E.M. Milner, and CA. Morehouse, Eds., American Society for Testing Materials, Philadelphia. pp. 29-47. ' 116 Canaway, PM, 1984. The Response of Lolium perenne (Perennial ryegrass) turf grown on sand and soil to fertilizer nitrogen Ill. Aspects of playability- ball bounce resilience and shear strength. The Journal of Sports Turf Research Institute. 60:27-36. Carrow, R.N., D.V. Waddington, and PE. Rieke. 2001. Turfgrass Soil Fertility and Chemical Problems: Assessment and Management. Chelsea, Mi: Ann Arbor Press. Chen Y., J. Tarchitzky, J. Brouwer, J. Morin, and A. Banin. 1980. Scanning electron microscope observations on soil crusts and their formation. Soil Sci. 130: 49-55. Cockerham, S.T., and D.J. Brinkman. 1989. A simulator for cleated shoe sports traffic on turfgrass research plots. California Turfgrass Culture. 39(3,4): 9-10. Crider, F.J. 1955. Root growth stoppage resulting from defoliation of grass. U.S. Technical Bulletin 1102. Foth, H.D. 1990. Fundamentals of Soil Science. New York, NY. John Wiley and Sons. 6055 R.L., and AG. Law. 1967. Performance of bluegrass varieties at two cutting heights and two nitrogen levels. Agronomy J. 59: 516-518. Harper, J.C. 1991. Aeration takes root in sports turf. SportsTURF. 7(7):17-21. Harper J.C., C.A. Morehouse, D.V. Waddington, and WE. Buckley. 1984. Turf management, athletic-field conditions and injuries in High School football. University Park, PA: The Pennsylvania State University, College of Agriculture, Agriculture Experiment Station Progress Report Number 384. Holmes, G., and M.J. Bell. 1986. A pilot study of the playing quality of football pitches. The Journal of Sports Turf Research Institute. 62:74-91. Johnston, W.J. 1984. Nitrogen source rate and time of application on bluegrass/ryegrass performance. Proceedings of the 38th Northwest Turfgrass Conference. 38: 23-29. Juska, F.V. 1967. Effects of nitrogen sources, rates, and time of application on the performance of Kentucky bluegrass turf. Proceedings of the American Society of Horticultural Science. 90: 413-419. Juska, F.V. 1961. Frequency and height of cutting bluegrass. Proceedings of the Annual Missouri Lawn and Turf Conference 2:1-2. 117 Kussow, W.R. 2000. Nutrient Management on Athletic Fields. 70th Annual Michigan Turfgrass Conference Proceedings. 29: 92-94. Lee, OK. and PE. Rieke. 1993. Soil Cultivation Effects on Establishment of Poa pratensis L. Sod. lntemational Turfgrass Society Research Journal. 7: 437-443. McClements |., and SW. Baker. 1994. The playing quality of natural turf hockey pitches. The Journal of Sports Turf Research Institute. 70: 13-26. Nelson, E. and Larson, B. 1994. Making athletic fields safer. SportsTURF. 10(9): 18-19. Orchard, J., H. Seward, J. McGivem, S. Hood. 1999. Rainfall, evaporation and the risk of non-contact anterior cruciate ligament injury in Australian Football League. The Medical Journal of Australia. 170(70): 304-306. Rogers, J.N., III, J.C. Stier, J.R. Crum, T.M. Krick, J.T. Vanini. 1996. The sports turf management research program at Michigan State University. Safety in American Football, ASTM STP 1305, Earl F. Hoemer, Ed., American Society for Testing and Materials, 1996, pp. 132-144. Rogers, J.N. and D.V. Waddington. 1993. Present Status of Quantification of Sports Turf Surface Characteristics in North America. lntemational Turfgrass Society Research Journal 7: 231-237. Rogers, J.N., D.V. Waddington. 1990. Effects of Management Practices on impact absorption and shear resistance on natural turf. 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Turfgrass Management. 4th ed. Prentice Hall, Upper Saddle River, NJ. Waddington D.V., and AS McNitt. 1995. Penn State research on surface characteristics of playing fields. The Keynoter. Lemont, PA: The Pennsylvania Turfgrass Council, lnc., 23(2): 5-7. Wilcox, H., H. Fox, and R. Beyer. 1965. Safer athletic fields. Athletic Journal. 45(10): 43. 119 Iiiji‘iiljjiijjgiiliiIliijii