Natural and reinforced grass%2c experiences learned and shared%2c 2011 (1).pdf

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Sportfloor TechnologieS Natural & reinforced grass qualities, 15.05.2011 page 1/48

Natural and reinforced grassFootball pitches

---- Quality assessment----

Experiences learned and shared

by

Sportfloor TechnologieS


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INTRODUCTION

What exactly is a natural grass pitch? _____________________________________ 3

STADIA GRASS PITCH QUALITIES

Some questions and answers concerning natural grass football pitches___________ 3

Natural grass types and qualities_________________________________________ 4Footballistic and technical qualities differences______________________________ 9

Natural grass grown outside of a stadium

• harvested in turf farms _____________________________________________ 10

• grown in box systems______________________________________________ 13

Reinforced natural grass

• reinforced with organic or artificial fibres within the grass roots_______________ 15

• reinforced with implanted fibres_______________________________________ 17

• reinforced with artificial fibres of a turf carpet____________________________ 19

Typical pitch constructions_______________________________________________ 24

Line markings_________________________________________________________ 28

ADDITIONAL PITCH INSTALLATIONS

Water sprinkler _______________________________________________________ 29

Soil heating __________________________________________________________ 31

Artificial lightening_____________________________________________________ 33

Artificial aeration below the root zone______________________________________ 34

MAINTENANCE __________________________________________________ 36

Cost comparison between the three mayor turf systems________________________ 37

Example of detailed yearly maintenance cost________________________________ 38

APPENDIX

Competition regulations_________________________________________________ 41

Extracts of studies and publications of reinforced grass_______________________ 42

Detailed footballistic test results__________________________________________ 46

Test template for natural and reinforced grass pitches_________________________ 47

Author Rolf HedigerExpert in sport surfaces / floorings; 30 years of experiencesDirector of a sport surface installation company; 1980 - 1997Sport expert, Sportfloor TechnologieS, since 1997Consultant of UEFA, Fifa, the Italian Football Federation (LND) and EFTGInitiator of the UEFA test manual and test criteria (2003); today’s FIFA Football Turf 2Star criteriaUEFA study comparing natural grass and Football Turf (footballistic qualities compared to injuries)in European stadia used by professional teams in the Champions League 2006-2008 und during the Euro08

Address 28, CorgeonCH-1095 [email protected] www.sportfloor.ch

Documentation Publication from the industry, Football Associations and communities


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INTRODUCTION

What exactly is a natural grass pitch?

Natural grass is something so common in our l ives that we take its very existence, and rampant use, for granted. Butwhat is grass and why do we spend so much time obsessing over it? Grass is the familiar name given to the family ofplants known as the graminae. The graminae family consists of over 6,000 species, making it one of the largest in life.

Grass, as a family, isn't limited to being something to just play football on. Bamboo rice, corn and oats are part of thegrass plant family and so are the plants that make sugar, liquor, bread, and many other staples of the average kitchentable. Though it may not seem obvious, even lawn grass contains the building blocks of all plant l ife: stems, roots,leaves, and yes, flowers. The flowers are quite obvious in grass plants like corn or even wheat. But in garden grass, youhave to get on your hands and knees to see how the grass functions and reproduces. The secret to grass, if there is one,is the fact that it all its growing takes place from what is known as the crown: a part of the stem that is at or near thesurface of the ground. Grass is adaptable and relatively easy to garden. You can mow a lawn and as long as the crownlevel isn't affected, the grass grows back. Likewise, if you grow grass and slice it from the ground as turf, as long as thecrown remains intact, the roots underneath can be sliced through below their tips. Grass reproduces by the seedingprocess, but also by stems that emanate from the crown. Stems that grow above the surface are called stolons. Stemsbelow the surface are called rhizomes.

STADIA PITCH QUALITIES Some questions and answers concerning natural grass football pi tches

What do the Football Associations require concerning the different types and qualities of grass used in itscompetitions?

• There are no regulation and recommendations whatsoever concerning the grass types and qualities used forfootball and so far no studies have been published by Football Federations.

What does the football player wish / request of a grass pi tch?

• A soft, not too deep surface.

• A full / dense and humid grass cover.

• An optical nice looking green surface.

What does the spectators like?

• An optically nice looking green pitch cover.

How many hours of play a natural grass pitch can be used?

• A natural grass pitch can, under normal circumstances, be used only a few hours per week, calculated over afull year between 400 to max. 700 hours, in order to keep a pitch in perfect condition.

What about stadium pit ches used for European Championship matches?In modern stadium, the surfaces can very often not be used as they are covered with:

• Artificial lighting to make the grass growing especially in the shades of the arena roofs.

• Covers over the entire pitch in order to blow warm air onto the pitch in order to grow the grass during the wintermonths.


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Natural grass quality

Pitches used for UEFA championship matches dur ing the season 2005 / 2006

Extremes overused pitches…

… and pitches covered with sicknesses

An average stadia grass density…. …… compared to an ideal grass density


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Perfect root density without too much thatch

Some renowned Greenkeeper of mayor stadium in Europe do think that the ideal compositionof a 100% natural grass pitch should be composed of:

• 70 – 90% Lolium Perenne

• 30 – 10% Poa pratensis

During the FIFA World Cup 2006 in Germany, two grass solutions have been adopted for all stadia pitches Type A

70% Festuca arundinacea 10% Lolium perenne

20% Poa protensis

Type A 80% Festuca arundinacea 20% Poa pratensis

• Poa pratensis= Kentucky blue grass = Common Meadow Grass = = Smooth stork meadow grass = Pâturindes prés = Wiesenrispe

• Lolium perenne = Ray-grass (english) = Perennial Ryegrass = Weidelgrass

• Festuca arundinacea = Fétuque élevée = Tall fescue = Rohr-Schwingel

Characteristics

Lolium Perenne Poa pratensisFine leaves Less playing resistance

Good playing resistance Need more maintenance and fertilisation

Good resistance against sicknesses Good resistance for a low cut, around 20mm

Fast growing Slow growing

Note: it seems that poa potencies can cause problemsbecause of its very strong roots which can lead to hightraction values = possible injuries.

Lolium Perenne Poa pratensis


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This graph show the type and composition of grass used in some of the mayor stadiumsand if any reinforcement is used, which type of reinforcement

0

10

20

30

40

50

60

70

80

90

100

A B E Ma MI MO P B1 B2 B G Z I K S V

Lolium perenne Poa pratensisPoa supina Kentucky BlueLolium & Poa in unknown proportion Limonta SportDD GrassMaster Fibreturf

It is estimated that an excellent football pitch has about 25’000 to 40’000 grass leafs per m2,which means an average of 300 Million grasses leafs per football pitch! A comparison: Golf Greens contain about 100’000 to 200’000 leafs par m2


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Maybe some stupid questionsMany football pitches in mayor stadium are reinforced with all types of artificial fibres systems or grow natural grasswithin artificial turfs.

• Are Football pitches with implanted artificial fibres or similar systems assimilated to natural grass?

• At which moment a football pitch is no longer considered natural?

• Is it when the numbers of artificial fibres per m2 are 10%, 20% or above 50% of a pitch?

Mix of natural grass and artificial fibres (National Stadium, San Marino)

Answer At the moment, 2010, the Football Associations (FIFA and UEFA) do not take this evolution into account.They are considering that a pitch which has any kind and number of natural grass within the playing surface is to beconsidered as natural grass. No any kinds of approvals or tests are required as with artificial pitches.


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Ar ti ficial help to reinforce and grow the natural grass

To strengthen the natural grass, in some stadia grass pitches, the grass root zone is reinforced with artificial ororganic fibres. Additional equipment is also installed in order to keep the grass growth as soil heating and aerationsystems below the root zone and above the turf as well as artificial lighting.

Implanted artificial fi bres and artificial light ing (London, Emirate Stadium)

Arti ficial aeration below and above the pitch


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Footballistic and technical quality differences

Footballistic and technical tests have been by UEFA made on European stadia with natural andreinforced grass pitches used for UEFA championship matches during the seasons 2006 to 2008 aswell as during the EURO08.The stadia pitches have been tested by 5 different FIFA accredited test laboratories and the testedpitches are

• 97 Football Turf

• 29 natural grass• 6 reinforced natural grass

During the same period the number and type of injuries where recorded by Prof. Ekstrand, a memberof the UEFA Medical committee, and a correlation between the footballistic pitch results and the injury studydata has been made.

Some test apparatus

Ball roll, Rotational resistance and Shock absorption / Energy restitution / V-deformation

ResultsUntil today, UEFA has not published the test report, therefore no detailed comments can bemade.In general, the pitch results show significant technical and footballistic quality differences between thetested pitches. Due to the technical and footballistic characteristics, the natural grass pitches have tobe divided into two groups; on one hand pitches with natural grass (pure top soil) and on the otherhand natural grass including different systems of root reinforcements.

Ball roll distanceTest results on different football pitches in mayor European stadia

Lenth of the ball roll in m compared to the grass height in mm

0

5

10

15

20

25

30

35

40

Ars enal april Arsenal

september

Barcelona Eindhoven

february

Eindhoven

september

Malta Moscow

Locomotif

Milan Porto

mm minimum maximum

A B C D E F G H IContrary to general belief (coaches and ground keepers), the grass density(grass cover) defines the ball speed and not the height of the grass!


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NATURAL GRASS GROWN OUTSIDE OF STADIA

Natural grass harvested in turf farms

Harvesting in rolls from 0.30m to 2.20m width and 15 to 35mm thickness

Installation during the EURO08 in Basel


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Installation for the European Champions final in Moscow (Luzhniki) 2008


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Covering the artificial turf wi th a natural grass pitch for the EURO08

Experiences dur ing the EURO08 in Bern Wankdorf (Swi tzerland) and Salzburg (Austria)

Af ter the EURO08, removal of the natural grass

Construction scheme for the EURO 08 in Bern and Salzburg


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Natural grass grown in box systems

Preparation and fi lling the modules with sand

Levelling the height ready to plant the grass

The modules are ready for the installation in the stadium


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The installation in the stadium


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REINFORCED NATURAL GRASS

Grass reinforced with organic or artific ial fibres within the grass roots

The marked overall improvement in football pitches probably really started in the late 70’s and early 80’s, with theintroduction of sand - dominant root zones.However as an infrastructure with 100% sand is unstable, various fibre reinforcement techniques in sand-dominant root zones represented a significant step forward in tackling the basic lack of stability inherent in suchroot zones.Two such techniques firstly, the Fibreturf system of random fibre orientation developed in the USA in order to usea stadium for concerts and other non sportive events and secondly, the DESSO GrassMaster system of ‘stitchedfibre’.This type of pitches are now relatively commonplace and are to be found in many top-class pitches and also onthe numerous training and academy pitches of the top tier clubs.

However, sand-dominant root zones by their very nature produce harder surfaces than soil root zones; fibre-reinforced sand-dominant root zones even more so. The development of maintenance techniques, particularlyVerti-draining and other forms of solid-tine aeration, has been very important, therefore, in enabling the groundsstaff to exercise control over the somewhat conflicting requirements of hardness v stability.

The majeure problems of all t his type of pitchesare felt and thatch!


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Fibrelastic, a product of Fibresand UK

Fibrelastic® pitches are both more player friendly and more grounds man friendly than existing fibre reinforcedsand dominant pitches and, as such, represent a further step forward in root zone technology for natural turfpitches. This particular grass root reinforcement lessens the surface hardness, reducing the risk of player injury,and improves both the surface resilience and traction. A typical Fibrelastic® Root zone (FERZ) would comprise 80% by volume sand and 20% by volume organic matterreinforced with both Polypropylene and Elastane fibres. The reinforced root zone is totally premixed at our

modern production facility and delivered to site in bulk tipper vehicles. A typical Football or Rugby pitch of 7,500 m2 would require 1,200 tonnes of FERZ to form the upper root zone ata depth of 100mm. The importance of this procedure makes it essential for the Fibrelastic® pitch to be laid by aqualified and specialist sports turf contractor.Fibrelastic is different to other fibre reinforced sand dominant pitches such as Desso GrassMaster and XtraGrass.These rely on synthetic grass fibres as the root zone stabiliser.The aim has been achieved by mixing silica sand, organic matter, rigid polypropylene fibres and flexible elastanefibres to produce a completely homogeneous blend which is termed a Fibrelastic® Root zone (FERZ).The fully pre-mixed blend is then supplied to site for the sports field contractor to lay typically as a 100mm thickupper root zone followed by surface preparation, fertilisation and seeding in order to produce the final natural turffinish.This ‘elastication’ of the pitch provides a much more player-friendly surface, with less jarring of the limbs and alower risk of injury. It is also less prone to surface disturbance, giving ball players a better grip.It’s easier to look after than most current pitches because it’s just as hard wearing but doesn’t get as many divots.

In order to keep making progress and particularly in order to address the hardness v stability situation, FibresandUK in 2007, after a two year research programme at the STRI, introduced a new dual fibre reinforced root zonetermed Fibrelastic.The Fibrelastic rootzone system should ensure a firmer more resilient playing surface and comprises silica sand,organic matter, rigid polypropylene fibres and flexible elastane fibres, which produce an ‘elastication’ of the pitch. As a result, the surface should be less tiring and more player friendly, with injuries to knees, ankles and lowerbacks less likely to occur. It also should make the surface less prone to disturbance, giving players a better grip.

The aim of the product was threefold: Firstly, a reduction in surface hardness = less jarring of limbs and lower riskof player injury. Secondly, an increase in surface resilience = more energy feedback to players feet, therefore, aless tiring surface. Thirdly, a further increase in root zone cohesion = increased traction, therefore, les surfacedisturbance.

The overall result of these three factors is a surface which has all the attributes of a typical fibre-reinforced sanddominant surface but which feels considerably softer and more akin to a soil based pitch in good condition.

For more details, refer to Appendix: extracts of studies and publications concerning Turfgrids, Fibersoil and similar products

Aviva Stadium, Dubl in


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Grass reinforced with implanted artificial fibres

GrassMaster, a product of Desso


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1. The leaf blades reside above the tops of the synthetic tufts creating a fully natural grass surface. If the turfcanopy is worn away, the sand based filled synthetic matrix continues to provide a consistent, sure-footedplaying field.

2. The grass roots become entwined in the matrix of synthetic tufts and, unimpeded, grow downward throughthe plastic mesh and into the foundation material below.

3. The predominantly sand fill layer is selected to be compatible with our site’s foundation material,

minimizing the potential for layering and assuring high water infiltration rates through the turf.4. The tough plastic mesh immediately below the vertical fibres acts as the anchor for the components above

it and provides additional horizontal subsurface load bearing capacity. Depth around 20cm every 2x2cmand above the ground between 15-20mm.

This means a reinforced Grass Master Football pitch contains approximately

20 Million synthetic fibers

together with 300 Millions of natural grass fibers


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Natural grass reinforced with artificial fibres of a turf carpet

XtraGrass, a product of Greenfields

XtraGrass™ is a grass reinforcement system natural grass grows through a specially woven synthetic turf fabric.1. The presence of the XtraGrass reinforcement, with or without polystyrene amendment in the root zone, does

not significantly affect plant development.

2. The addition of polystyrene amendments to the root zone of the XtraGrass system significantly reduces

hardness of the surface, resulting in values well within the acceptable range for football.

3. Ball rebound resilience followed a similar pattern to hardness, with all values within the acceptable range.

4. All trials with XtraGrass reinforcement had significantly higher traction values than the un-reinforced natural

grass reference trials. The advantage of using XtraGrass reinforcement is evident in that even under high

intensity wear it still has better traction than un-reinforced natural turf subjected to moderate wear.

5. Infiltration rates for all treatments XtraGrass were very good.

6. Furthermore no hydrological barriers are being created for drainage and irrigation water to be obstructed to

move to lower levels of the playing field.

7. The results for hardness, ball rebound and traction from the XtraGrass reinforcement are comparable with

measurements made by STRI on professional natural turf football pitches during studies in 2000-2005.

Installation

XtraGrass™ will be supplied to site in 1,4m wide rolls or alternatively pre-manufactured into rolls of 4,2m width.Each roll or section of rolls will be laid on the prepared root zone surface ensuring the level and evenness of theroot zone will remain within the required specification. The joints will be sewn together using a hand operatedsewing machine with cotton thread. After the rolls have been sewn together the carpet is stretched over the pitchsurface, the root zone mix topdressing will be applied via a special topdressing unit either tractor mounted orstand alone. The root zone mix will be dried for this purpose. The infill rate is set for 10-15mm of material at eachapplication, followed by a tractor mounted brush in order to lift the XtraGrass™ fibres. The total infill rate of 45-50mm will be achieved after 3-4 applications. Once the final level and surface evenness has been achieved theXtraGrass™ fibres will stand up and show for a minimum of 80%. A pre-seeding fertilizer application will be addedto the root zone prior to seeding.


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The pitch will be seeded using a Brillion type of seeder ensuring the integrity of the XtraGrass™ system will notbe damaged. The type of grass seed and application rates as well as seeding depth is depending on the climateconditions at the project location and will be specified during the initial site meetings. After seeding the pitch will be rolled with a light land roll to cover and fix the seed in the top of the root zoneprotecting it from washing out or animal damage. Regular watering will commence after seeding in order toencourage the germination of the grass. Once the grass has germinated and the plants reach a length of 50mm,the initial cut will be made using a pedestrian rotary mower. A detailed maintenance program will be prescribed toensure swift settlement of the grass within the XtraGrass™ system.

Advantages

The stability of the pitch is enhanced substantially by combining the strengths of synthetic and natural turf

Increased hours of use on natural turf: up to 1000 hours of playing time can be achieved with the correct

maintenance program

Can be grown as big roll, 40-50mm thick, and cut turf.

The open structure avoids compaction, which can be enhanced by additions in the lower root zone

XtraGrass™ allows traditional turf management practices to be carried out

The increased strength of the sward and stability of the pitch, pitches can be used for different sports, such as

rugby and soccer

Excellent playability in poor weather conditions due to excellent stability and water permeabilityThe synthetic turf fibres have a green ‘natural grass-like’ appearance and protect root zone and grass plants

Level and smooth surface

Easy to exchange (parts of) the pitch with new XtraGrass turf.

PITCH PERFORMANCE CRITERIA - STRI TESTS


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Green Live, a product of Limonta

Green Live is a grass reinforcement system where natural grass grows within a special organic infill material andartificial fibres.


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Base: Volcanic gravel

Arti ficial grass: Limonta Diamond 60mm

Infill: Organic performance Infill “ Pro-Geo”

Seeding: Lolium perenne and Poa pratensis

Usage: 5-6houres a day, summer and winter

Maintenance Clipping ( mowing: 2-3 x per week in the growing season Fertilisation every 2 months Harrowing, brushing and removal of the thatch 2 x a month Over seeding: executed the traditional way

No maintenance work for: Top dressing, coring, sodding, verti-cutting, addition of sand, aeration Preventive weed control: no weeds do grow in this type of pitch Pest control: no preventive treatments (only of any symptoms manifest / are visible)

Watering 5-6mm water per day

Spring 2 x per week Summer 3 x per week Autumn 1 x per week Winter nothing


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Installation in the National stadium of San Marino


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SOME EXAMPLES OF PITCH CONSTRUCTIONS

Construct ions in Germany; according to DIN 18 035/4

• Ray grass

• Top soil mixed with volcanic gravel, 5cm; or

• Top soil & sand 50/50 15cm (coarse sand 30%, fine sand 15%, chalk 1.5%, argil less than 5%, organic materialmin.3.5%, azotes min. 0.1%, potassium 0.025 and 0.05%, PH 5 to 8)

•

Crushed rock 10 – 20cm• Drainages on top every 120cm, depth 35cm, with 5cm with round gravel min. 5cm all around

• Drainage below every 6 to 12m, diam. 60-80mm, depth min. 30cm, slope min.03%

• Bottom of the excavation, slope 0.5 - 1%

Stade de Gerland in Lyon, France

• 50% ray grass and 50% poa pratensis

• Prefabricated turf

• Supporting layer: 160mm volcanic soil (pouzzolane - scoria carboniferous)

• Gravel layer: 10/20 of 15mm

• Gravel layer: 20/40 of 40cm

• Drainages: every 6 to 10m, diam. 80 to 100mm

• Bottom of the excavation, slope 0.5 - 1%

Stade de Genève, Switzerland

• 50% ray grass and 50% poa pratensis

• Prefabricated turf

• Support: 150mm volcanic soil (pouzzolane 0/6 - scoria carboniferous)

• Layer of pouzzolane 15cm

• Gravel layer, 30cm

• Drainages

• Bottom of the excavation


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Example of cross sections

System with drainages

System without drainages (water permeable bottom of excavation)

Example: Stade de Genève


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Construction experiences outside of Europe

Example from Asia

Construction parameter

• River gravel as foundation

• Standard drainage system

• 5cm not washed see sand

• Grass cover with 50% Princess and 50% Sydney couch (20/20kg/m2)

The field and it’s surrounding with a grass cover without any treatment.

Comparison of two infrastructure compositi on on the same pitch. Sydney couch grass and treated invadergrass (yellow colour). Bigger invaders have to be removed by hand-picking.

A pitch wi th excel lent deep growing roots and a mixture of Sydney and Princess Grass


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A pitch wi th Sydney blue couch

Comparison: irrigated pit ch and non irr igated and treated spectator area

Base with purely natural top soil …… and enhanced with sand

Example from South-Africa

SSSouth African sports fields contain warm-season grass types, usually Kikuyu (Durban’s Moses Mabhida stadium isthe only match venue containing a warm-season grass called Cynoden) as Kikuyu grass doesn’t perform well in thesalty environment of Durban because it is inexpensive and drought tolerant.The FIFA however demanded that all World Cup matches must be played on cool season Ryegrass, because it isaesthetically more pleasing in colour for the television-screen. This is possible, because the World Cup is beingplayed during the South African winter, when the Kikuyu goes dormant.TTTherefore, all 72 playing fields (fields containing Rye grass spread all over the country are dedicated to the WorldCup) assigned for the World Cup 2010 were recently renovated with fraise mowing to remove the top of the Kikuyuplants leaving only the roots. These roots are very important as they serve as a reinforcement of the turf and create abase for the roots of the Ryegrass to hold on to.

The pitches were then aerated using a Verti-Drain, cracking the soil with solid tines and thus creating ideal growingconditions for the new seed which was sown using a Speed-Seed.This seeder creates close on 1900 holes per m2 with random dispersal of seed to leave no drill lines.TTThe procedure was finished off with the surface receiving a thin layer of sand from, for example, a Rink brushspreader. This ensured the seed was allowed the maximum soil contact for optimum germination. This is followed byvery heavy irrigation, between 100.000-150.000 litters per field per day, so that the thirsty Ryegrass could grow anddevelop quickly. (Information from STRI)


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Line markings

Visible displacement of the pitch playing lines to avoid overuse of the grass

Note:The security zone for UEFA is minimum 3m, however this depend national regulation.In addition, it is recommended to add a stabilised 3m surrounding between the security zone and the spectators.Elements such as filed markings goalpost etc…, have to be according to the laws of the game and the local competition regulation.


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ADDITIONAL PITCH INSTALLATIONS

Water sprinkler

Water sprinkler ins talled at the edge of the pitch

This type of sprinklers should not be installed in the middle of the pitch, as they can endanger theplayers.


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If irrigation systems are installed within the pitch, they must be small enough as not to affect andendanger the players.

Multiple irrigation system used in San Marino fo r a reinforced natural grass pit ch


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Soil heating

Samples of soil heating systems (with w ater or w ith electricity)


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Example


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Ar tif icial l ightening

Arsenal, Emi rate Stadium

Quote Paul Burgess, Greenkeeper of ArsenalIn order that the system is useful it needs 9 units for a half pitch, which cost approx. 1 Mio. SFr, withrunning cost per year of SFr.180’000.- . During the winter months, the lighting is used every day / 24hduring 6 months (except on match day).Result: the grass cover will never be below 90% (if the additional daily maintenance is done).


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Ar ti fic ial aeration below the root zone

SubAir system

The SubAir system applies a vacuum within the subsoil drainage pipe network to increase the rate at which wateris moved from the surface and through the soil profile. The management of subsoil moisture also helps with

temperature moderation in the entire soil profile.

SubAir also applies pressure to force air from the subsoil pipes through the soil profile. This patented technologycreates air movement that provides aeration while moderating temperature in the root zone.

The SubAir aeration and moisture removal system promotes healthier, stronger playing surfaces through moisturecontent management, subsurface aeration, and root zone temperature control. As a result, SubAir providesoptimum aerobic subsurface growing conditions.SubAir’s team of agronomists and engineers has developed a complete system to accelerate moisture removaland increase gas exchange. The SubAir Sport system helps provide an optimal growing environment for anyplaying surface – increasing playability and producing a more enjoyable experience for players and spectators.Through the use of the AirWave monitoring and control system, SubAir Sport is automated based on datareceived from the field.

A SubAir Elite vault, housing the blower that provides both vacuum and pressure mode, is connected to the pipingnetwork. A Distributed Separator is connected to the green’s drainage network. This patented assemblyseparates the air from the water so that the air flows to the SubAir vault and the water drains to the outfall. A Dual

Valve is used on the end of each outfall to create an air lock. This directs the air through the soil profile so it doesnot escape through an open ended pipe.


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OSMO-DRAIN System

The system for the

• Aeration

• Ventilation

• Watering

• Drainageof Football pitches can be installed into an existing pitch par a special cut machine. On the edge of the pitch every 25cma cut is made with a width of 16mm. During the same work action, a tube is laid without mixing the different subsoil

stratus. The only visible part of the work will be outside of the playing surface for the access tubes.

Aeration and venti lat ion Air can be compressed pushed through the tubes into the sub-soil. Each sector of the pitch can be treated individual.Within one hour the full pitch can be treated. On the contrary it is possible to make an aspiration of ambient oxygen fromthe top of the pitch into the sub-soil.

Watering and drainageDepend the amount of rainfall or the size of the shade covering, the water quality can be adjusted for each sectorindividually and gradually.

Access pipes….. and installation of the tubes

Existing pitch with a new installation


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A pitch being over seeded with theSpeed Seed, a machine which isproducing nearly 2000 holes per m2for the seed to drop in. Immediately

behind the Speed Seed, the soil waspenetrated vertically by hollow coringtines installed on the Verti-DrainMustang.

Thus, the soil and the seed werebrought to the surface of the field.This was followed by a drag mat,which pulled the seed and soilmixture into the millions of holesensuring a maximum germination

A pitch being over seeded with theSpeed Seed, a machine which isproducing nearly 2000 holes per m2 forthe seed to drop in. Immediately behindthe Speed Seed, the soil waspenetrated vertically by hollow coringtines installed on the Verti-DrainMustang.

Verti-Drain model hollow cores thestadium pitch 300mm deep in order toestablish a perfectly drainingsubsurface, before the new grass coverwas brought on.

MAINTENANCE

Example by Redexim

After the installation of a new grasscover of approximately 3 ½cm thick,it was then immediately followed by atreatment with the Verti-DrainMustang with thin solid tines, in orderto establish quickly the contact of thenew grass cover with theunderground.

A top dresser spreads the sand

between the grass blades, 2 weeksbefore the first game.


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MAINTENANCE COST

Cost comparison between the three mayor tur f systems

Natural grass

Reinforced natural grass (example : GreenLive)

Football Turf (artificial turf)

GRASS TYPE natural grassReinforced

natural grass Football Turf

Maximal hours of usage per year 500 - 700 700 - 1000 1800

Pitch size: 105 m x 68 m plus 3m securi ty

Cleaning 2 hours per week 7’500.00 7’500.00 5'000.00

Decompaction 7'900.00 3'600.00

Line marking 9'600.00 9'600.00

Mowing 17'200.00 17'200.00

Rolling 3'800.00

Irrigation 12'000.00 12'000.00 5'000.00

Fertilisation 4'700.00 4'700.00

Treatments 1'600.00 1'600.00

Slitting 2'500.00

Verti-cutting 6'500.00

Replacements 4'300.00

Dressing 3'000.00

Emptying the sprinkler system during the winter 400.00 400.00 400.00

Harrowing 4'500.00

Over seeding 2'500.00

Replacement or removal of granules 2'500.00

Brushing 4'500.00

Divers (fuel and power) 2'500.00 2'500.00 2'500.00

TOTAL COST 83'500.00 62'500.00 26'000.00

COST PER ONE HOUR OF PLAY 140.00 75.00 15.00PITCH CONSTRUCTION COST 600’000.00 1'700'000.00 1'500'000.00

COST PER ONE HOUR OF PLAYDURING 10 YEARS

225.- 265.- 95.-

RENOVATION COST 100'000.- 300'000.- 600'000.-

COST PER ONE HOUR OF PLAYDURING 20 YEARS

190.- 190.- 70.-


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Example of a detailed yearly report from a communi ty in the Geneva area

Usage in hours of a football pitch during one year HOURS

Janvier 0

Février 51

Mars 102

Avril 102

Mai 102

Juin 51Juillet 0

Août 51

Septembre 102

Octobre 102

Novembre 102

Décembre 51

Total 816

Entretien

Electricité / lumière terrain / an: 32 KW x 52 sem. X 5,6 h 9'318.40 0.2175 2'026.75

MO / Nettoyage du terrain par an : 2 heures par semaine 104.00 48.32 5'025.28

MO / Elimination des déchets : 1 heure par semaine 52.00 48.32 2'512.64

MO / Nettoyage des vestiaires : 2-4 vestiaires 195.00 48.32 9'422.40

1. Décompactage 7'865.552. Marquage 9'610.24

3.Tonte 17'171.52

4. Débroussaillage clôture 745.44

5. Roulage terrain 3'787.20

6. Arrosage 11'900.80

7. Engrais 4'727.40

8. Traitements terrain 1'621.28

9. Traitements clôtures 877.20

10. Fendeuse 2'524.80

11. Carottage sur-semi 6'417.20

12. Placage 4'212.64

13. Sous-sablage 3'000.00

14. Mise en eau / hors gel 386.56

15. Divers travaux d'entretien 2'512.64

TOTAL entretien 77'360.47 77'360.47

TOTAL DES COUTS D'ENTRETIEN ANNUEL 96'347.54

(*) variable : le prix de revient de la MO

Coût par heures (816) 118.00

Coût par heures (816) de jeux par jouer (22) 5.40

Coût de la construction à neuf, durée de vie 30 ans 600'000.00

Coût d'un plaquage après 15 ans 250'000.00

Coût d'entretien pendent 30 ans, 27 x 100'000.- 2'700'000.00

Coût de l'amortissement, 15 ans 600'000.- & 250'000.- 600'000.00

Coût total sur une dure de vie de 30 ans 4'150'000.00

Coût par heures (816) 170.00

Coût par heures (816) de jeux par jouer (22) 7.70

Recyclage 60 m3/30 tonnes x 28 semaines (*)estimation faite à 500 kg au m3 30.00 160.00 4'800.00


39/48


Coût de revient détaillé1. Décompactage confié à une entreprise extérieure 7'865.55

Période et fréquence : de 1 x par an à 1 x tous les 2 ans

2. Marquage

Période 8 mois

Fréquence 1 x par semaine

Durée 1 heure

Mo interne 32 heures 32.00 48.32 1'546.24

Heures machine 32 heures 32.00 120.00 3'840.00Matériels 20 kg = CHF 132.-- par semaine 32.00 132.00 4'224.003.Tonte

Période Avril à octobre = 28 semaines

Fréquence 1,5 x par semaine en moyenne

Durée 1 heure

Mo interne 1 h x 1,5 x 28 semaines (tonte) 42.00 48.32 2'029.44Heures machine 1 h x 1,5 x 28 semaines (tonte) 42.00 120.00 5'040.00

Mo interne 0.75 h x 1,5 x 28 sem. (ramassage) 31.50 48.32 1'522.08

Heures machine 0.75 h x 1,5 x 28 sem. (ramassage) 31.50 120.00 3'780.00

4. Débroussaillage clôture

Fréquence 3 x par année

Durée 1,5 heure

Mo interne 1,5 x 3 4.50 48.32 217.44

Heures machine 1,5 x 3 4.40 120.00 528.00Recyclage compris sous point 3 160.005. Roulage terrain

Période Avril-octobre sans l'été = 10 sem.

Fréquence 1,5 x par semaine

Durée 1,5 heure

Mo interne 1,5 h x 1,5 x 10 semaines 22.50 48.32 1'087.20

Heures machine 1,5 h x 1,5 x 10 semaines 22.50 120.00 2'700.00

6. Arrosage

Période Mai à septembre = 20 semaines

Fréquence 3 arrosages par semaine

Consommation 3 x 86 m3 x 20 semaines 5'160.00 1.26 6'501.60

Mo interne 1 h x 3 x 20 semaines 60.00 48.32 2'899.20

Matériels Remplacement pièces d'arrosage 2'500.00

7. Engrais Fréquence 5 x par année

Durée 1,5 heure

Mo interne 1,5 h x 5 7.50 48.32 362.40

Heures machine 1,5 h x 5 7.50 120.00 900.00

Matériels 5 x 7 sacs de 25 kg/CHF 99.-- 35.00 99.00 3'465.00

8.Traitements terrain

Fréquence 2 x par année pour 6'000 m2

Durée 2 heures

Mo interne 2 h x 2 4.00 48.32 193.28

Heures machine 2 h x 2 4.00 120.00 480.00

Matériels 30 litres x 2 60.00 15.80 948.00

9. Traitements clôtures

Fréquence 2 x par année pour environ 50 m2Durée 2,5 heures

Mo interne 2,5 h x 2 5.00 48.32 241.60


Matériels 1 litre x 2 2.00 17.80 35.6010. Fendeuse

Période Février à octobre


Durée 1,5 heure

Mo interne 1,5 x 10 15.00 48.32 724.80

Heures machine 1,5 x 10 15.00 120.00 1'800.00


40/48


11. Carottage sur-semi

Fréquence 2 à 3 x par année pour 6'000 m2

CARROTTAGE

Durée 2 heures

Mo interne 2 h x 3 6.00 48.32 289.92

Heures machine 2 h x 3 6.00 120.00 720.00

Matériels 0,015 kg x 6'000 m2 x 3 270.00 9.00 2'430.00

PASSAGE DE LA GRILLEDurée 0,75 heure

Mo interne 0,75 h x 3 2.25 48.32 108.72


PASSAGE DU ROULEAU

Durée 0,75 heure

Mo interne 0,75 h x 3 2.25 48.32 108.72


EPANDAGE PAILLE 1 X par année

Durée 4 heures

Mo interne 4 h x 3 12.00 48.32 579.84

Heures machine 4 h x 3 12.00 120.00 1'440.00

Matériels 2 rouleaux à CHF 100.-- pièce 2.00 100.00 200.00

12. Placage Pour une surface d'environ 200 m2

Fréquence 1 x par annéeDurée 2 jours pour 2 personnes

Mo interne 2 jours x 8 heures x 2 personnes 32.00 48.32 1'546.24

Heures machine 0,5 jour x 8 heures x 5 personnes 20.00 48.32 966.40

Matériels 200.00 8.50 1'700.00

13. Sous-sablage confié à une entreprise extérieure 3'000.00

Fréquence 1 x tous les 2 ans

14. Mise en eau / hors gel

Période Printemps - automne


Durée 4 heures

Mo interne 4 h x 2 8.00 48.32 386.56

15. Divers travaux d'entretien

Période Toute l'année

Fréquence 1 x par semaineDurée 1 heure

Mo interne 1 h x 52 52.00 48.32 2'512.64


41/48


APPENDIX

UEFA Competition regulations

The UEFA competition regulations are edited new each year and refer to:

• Technical Recommendations and Requirements for the Construction or Modernisation of Football Stadium,

and

• Regulations of the UEFA Champions League

The regulations require a playing field in perfect playing condition:

absolutely smooth and level

with an efficient watering system

equipped with a underground heating system in cold climates

with a recommended field area of 120m x 80m

with playing dimensions of 105m x 68m

with a natural grass cover or an artificial turf*

Arti cle 7 – Playing sur face

1 The stadium must be equipped with either a natural playing surface or a Football Turf (artificial turf).

2 A Football Turf must meet all of the following conditions:

a) it must have been granted the required FIFA licence, which can only be delivered after the turf in questionhas been tested by a FIFA-accredited laboratory as meeting the FIFA quality standards for artificial turf;

b) it must meet all the requirements of the national legislation in force;

c) its surface must be green.

UEFA Cup and UEFA Champions League competi tions

If the cover is a Football Turf, intended to be used for an UEFA competition, then the pitch has to be certifiedaccording to the FIFA Quality Concept 2 Star system and must show a valid test certificate (validity: maximum 12months).

UEFA competitions for Under-17, Under-19, Under-21 and women

Type of test certificate depending of the UEFA product manager; minimum according to IATS.

Swiss Competition regulations

The field of play must be absolutely smooth and level.

It must be equipped with a drainage system to eliminate the possibility of its becoming unplayable due to flooding.It must comply with the following dimensions and requirements

Stadium category Length Width Additional requirements

Super league

Challenge league105m 68m

1st league 100m 64m

100m 64mRegional leagues

or proportionally maximum 10% less

SlopeLength: max. 0.5%Width: max 1%

The stadium must be equipped with either a natural playing surface or a Football Turf (artificial turf).

Stadium category Football Turf

Super league

Challenge leagueFIFA 2 Star

1st league min. FIFA 1 Star

Regional leagues min. CEN-EN


42/48


Extracts of s tudies and publications

Turfgrids, FibersoilCopyright ©2007 Fibersoils. Geofibers®, TurfGrids®, and Sportgrids®This study was conducted to determine the effect of various

types and rates of soil reinforcing materials on soil bulk density,

soil water content, surface

hardness, and turfgrass density of a high-sand root zone exposed to three levels of simulated

traffic (wear). Six soil reinforcing materials were mixed at

varying rates with a high-sand root zone. These included DuPont Shredded Carpet, Netlon, Nike Lights, Nike Heavies, Turfgrids,

and Sportgrass. Three

levels of wear were imposed on each treatment. The types and rates of reinforcing materials had varying effects

on surface hardness, bulk density,

water content, and turf density of the root zone. Surface hardness and soil bulk density were

correlated during the 2-yr test period (r = 0.63). The

reinforcing treatments that lowered soil bulk density and surface hardness

were DuPont Shredded Carpet, Nike Lights, and Nike Heavies.

Reinforcing

material treatments that increased or did not affect soil bulk density generally resulted in increased surface hardness

compared with nonamended

controls. These treatments included Netlon and Turfgrids. Surface hardness generally became more pronounced as the level of wear increased forNetlon, Turfgrids,

and Sportgrass treatments. The Sportgrass treatment consistently

measured lower in soil water content than the control and had

a

turfgrass density lower than the control on all rating dates in 1996 but did not differ from the control in 1997. Athletic

field managers considering using

reinforcing materials should be aware that the type of material and rate influence athletic

field surface hardness.

Table 5. Mean surface hardness, soil bulk density, and soil water content values for treatments across all wear levels.

SOIL REINFORCING MATERIALS have been mixed with high-sand athletic field root zones in an attempt to improve surface stability. Althoughsome of these materials have demonstrated improved

playing surface quality through greater surface stability, there

is evidence that certain reinforcing

materials increase soil bulk density and surface hardness (Baker, 1997). Surfaces that

are hard can be dangerous to athletes (Rogers and Waddington,

1990). Reinforcing materials considered for use in athletic

field root zones should provide surface stability benefits without

increasing surface hardness

to unacceptable levels.

Baker (1997) reviewed much of the research on synthetic reinforcing materials for turfgrass soils and proposed two broad categories:

(i) randomly

oriented fibers, filaments, or mesh elements and (ii) horizontally placed fabrics. Most randomly oriented fiber

reinforcing materials studied in turf consist

of relatively short polypropylene fibers. Baker and Richards (1995) incorporated

both straight and crimped polypropylene fibers (36 mm in length

and

113 µm in diameter) into sandy soils at rates up to 7.5 g kg

-1. At the 4.0 g kg

-1 rate they reported increased surface

hardness on two of the 11 rating

dates. When the rate was increased to 7.5 g kg

-1, significant increases in surface hardness were

reported on eight of the 11 rating dates. During dry

conditions at the end of the study, the fiber reinforcing materials made

the surface harder than the range the researchers considered

acceptable for

player/surface impact.

Mesh elements were first evaluated as a soil reinforcing material

by researchers attempting to increase the strength of sand for

engineering applications such as support beneath building footings (Mercer et al., 1984; McGown et al., 1985). Mercer et al. (1984)

stated that to

optimize soil strength, the size and shape of the filaments comprising mesh elements must be related to the

size of soil particles in which they are

placed. In order not to weaken the soil, the addition of mesh elements must not significantly

decrease soil bulk density (Mercer et al., 1984). Mercer et

al. (1984) found that at mesh contents up to 5.5 g kg

-1, the

bulk density of the mixture was the same or greater than the

sand alone.

Turfgrass scientists

have evaluated mesh elements, similar to those described by Mercer et al. (1984), as reinforcing materials

for athletic field root zones. Under simulated

soccer-type wear, Baker (1997) reported no significant effect of mesh elements

on the retention of grass cover, ball rebound, or surface hardness.

In a

study without simulated wear treatments, Beard and Sifers (1993) found an increase in soil water content and a small decrease

in surface hardness

values with increasing concentrations of mesh elements. In another mesh element study using a method

different from Beard and Sifers (1993) to

assess surface hardness, Canaway (1994) reported a general increase in surface hardness

as the rate of mesh elements in sand increased.

Richards (1994) conducted a laboratory study in which mesh elements were mixed with sand and compacted in 100-mm diam. cylinders.

The results

indicated reduced soil bulk density and increased total porosity of the mixture with increasing rates of mesh

elements. These results are not consistent

with the civil engineering work of Mercer et al. (1984) where the mesh elements either

slightly increased or had no effect on soil bulk density.

Another

type of reinforcing material that has been amended into turfgrass soils is shredded carpet. McNitt and Landschoot (2001b)

mixed shredded carpet

fibers into a sand-based modular turf system and found a reduction in divot size and surface hardness.

Shredded carpet is the shredded remains of

predominately nylon carpet fragments that include both pile and backing. The yarn-like

fibers range in length from 20 to 610 mm. Although shredded

carpet has not been widely studied in turf systems, some engineering research has shown that increasing rates of continuous yarn

up to 1 m in length

increased soil strength significantly more

than an equal weight of shorter yarn (Leflaive, 1982). Whereas

the strength imparted by shorter fibers is dueto friction between individual soil particles and the fibers, Leflaive (1982) explained

that continuous yarn increases soil strength by coiling tightly

around

groups of soil particles. In addition, the random looping and crossover of yarn fibers results in a tightening of slack

sections as further soil loading

occurs, thus increasing reinforcement. The conflicting soil bulk density results obtained by civil

engineers and turfgrass researchers for mesh element

reinforcing materials and the varying results obtained for surface hardness

of reinforced sand indicate that additional research is needed

on the effects

of soil reinforcing materials in high-sand athletic field root zones. Also, shredded carpet should be evaluated

as an amendment in high-sand root zones

to determine its effect on surface hardness, soil bulk density, and soil water content

under different levels of wear.

The objective of this study was to

evaluate the effects of varying rates and types of soil reinforcing materials on the surface

hardness, soil bulk density, and soil water content of a sand

root zone after wear is applied.

Descriptions of Reinforcing Materials Randomly Oriented Fibers, Filaments, or Mesh Elements DuPont Shredded Carpet. DuPont Shredded Carpet was obtained

from DuPont Nylon (Chestnut Run Plaza, Wilmington, DE) and is

the shredded

remains of carpet fragments that include both pile and backing. The shredded carpet is not commercially available,

but is a component of a sand-based

modular turfgrass system called GrassTiles (Hummer Sports Turf, Lancaster, PA). DuPont

Shredded Carpet is 70% nylon, 12.2% calcium carbonate,

10.7% latex, and 7.1% polypropylene on a weight basis (V.J. Kumar,

1998, personal communication). On the basis of 100 randomly

selected carpet

fibers, the average length was 135 mm, and the range was 20 to 610 mm. Fifteen carpet fibers were randomly

selected and measured for width. The

width of a carpet fiber averaged 2.4 mm and ranged from 0.5 mm to 4 mm. The compressed

and uncompressed density of a mass of shredded carpet

was measured

using a 1000-mL cylinder. The uncompressed density was determined

by measuring the dry weight of shredded carpet required toloosely fill a 1000-mL cylinder. The compressed density was measured

using the same mass of carpet compressed in the 1000-mL cylinder

using a 1-

kg weight. The compressed and uncompressed densities of the shredded carpet were 0.153 and 0.073 g cc

-1, respectively.

Netlon. The Netlon discrete mesh elements were supplied by Netlon Ltd. (New Wellington, St. Blackburn, U.K.). The mesh is manufactured

from

extruded polypropylene and has a mass per unit area of 52 g m

-2. The filament thickness is 0.50 mm (vertical medial

diameter) and 0.48 mm (horizontal

medial diameter). The filaments are arranged in a grid, creating rectangular openings that are

6.7 by 7.1 mm. Each element is 100 by 50 mm.

Nike Reuse-A-Shoe Materials. The Nike Reuse-A-Shoe materials are the shredded remains of used athletic shoes. In the shredding

process, the

entire shoe is granulated before the components are separated by screening and floating and sinking in water.

The Reuse-A-Shoe materials currently

do not have a size specification. Their gradation is a result of passing granulated shoes through

a 16-mm screen in the primary granulator and a 19-mm

shaker screen.

The materials that make up a shoe vary substantially. Most shoes

have uppers, midsoles, and outsoles (Malloch, 1996). The most

prevalent materials in the upper shoe component are nylon, synthetic leather (polyester with polyurethane coating), leather, cotton,

polychloroprene

(neoprene sleeves), polyester, polyurethane open cell foam, and cellulose. The midsole contains polyurethane

and ethylene vinyl acetate and the

outsole contains styrene butadiene rubber, polybutadiene (synthetic rubber), and natural

rubber (Malloch, 1996).

Nike supplied two materials from the

Reuse-a-Shoe program for this study: Nike Lights and Nike Heavies. Samples of the materials

produced at the Wilsonville, WA, processing site were

taken on 6 Sep. 1996 by technicians working on the project (Malloch, 1996).

The Nike materials were analyzed by the technicians for

purity, density,

and gradation. The Nike Lights contained 740 g kg

-1 uppers, 230 g kg

-1 midsole, and 30 g kg

-1 outsole. The

Nike Heavies contained 150 g kg

-1 uppers,

510 g kg

-1

midsole,

and 340 g kg

-1

outsole.

The compressed and uncompressed densities of the Reuse-a-Shoe

materials were measured to make acomparison with the Shredded Carpet used in this study. The uncompressed density of each

material was determined by weighing loosely placed

samples in a 1000-mL cylinder. A compressed density was measured by applying

a 1-kg weight to each material in the 1000-mL cylinder. The

compressed and uncompressed densities of the Nike Lights were 0.107 and 0.053 g cc

-1, respectively. The compressed and uncompressed

densities

of the Nike Heavies were 0.244 and 0.200 g cc-1

, respectively.


43/48


Turfgrids. Turfgrids is a commercially available, polypropylene fiber reinforcing material manufactured by Synthetic Industries,

Inc. (Chattanooga, TN).

It is 99.4% polypropylene and individual fibers are 38-mm long and 5-mm wide. Each individual fiber is

fibrillated to form a net-like structure of finer

fibers (fibrils). When mixed with soil, each fiber expands and the net-like configuration

of fine fibers is randomly-oriented throughout the root zone.

Horizontally Placed Fabrics Sportgrass. Sportgrass is a commercially available product manufactured

by Sportgrass, Inc. (McLean, VA). Sportgrass consists of a polypropylene

woven backing with 24 yarn strand ends per 25.4 mm in the lineal direction and 11 yarn strand ends per 25.4 mm in width. Yarn

strands are 11 000

denier (1.0 denier is equal to the fineness of a yarn weighing 1.0 g for each 9000 m). The woven backing

is tufted with fibrillated polypropylene tufts. In

the lineal direction there are 16 tufts per 102 mm. In width, the tufts

are 9.5 mm apart. The pile height is 32 mm. The individual tufts

form a net-like

configuration when expanded. A fibrillated tuft is 6700 denier (W. Cook, 1998, personal communication).

Treatment Rates Treatment rates of reinforcing materials were based on industry

recommendations, previous research, and preliminary lab tests.

The preliminary

laboratory tests included mixing different rates of reinforcing materials (except Sportgrass) with the sand and

peat mixture used in the main field study.

The root zone was mixed on a volume basis using nine parts sand to one part sphagnum

peat. Two hundred-millimeter-diameter polyvinyl chloride pipe

was filled 150-mm deep with each mixture and compacted with a Proctor Hammer (American Society for Testing and Materials, 1999).

Bulk density,

total porosity, aeration porosity, and capillary porosity were determined for each mixture using a

tension table and methods similar to those listed in

American Society for Testing and Materials (1997). Two rates were chosen

for Netlon and Turfgrids; 3 and 5 g kg

-1. The 3 g kg

-1 rate

of reinforcements

for the Netlon and Turfgrids were based on standard industry recommendations for sports fields (Netlon

Advanced Turf, Blackburn, UK; and Synthetic

Industries, Chattanooga, TN). The 5 g kg

-1 rate for both of these products is considered

high for sports fields and is primarily recommended for turfgrass

horse racing track installations. Rates exceeding 5 g kg-1

were not used in this study because of the difficulty in maintaining

a homogenous blend of

sand root zone and reinforcing material in preliminary studies.

Preliminary studies indicated that the DuPont Shredded Carpet

could be mixed

effectively at rates up to 30 g kg-1

. Nike Lights and Nike Heavies treatments could be mixed at rates higher than

30 g kg

-1, but due to a lack of available

material and to make a rate comparison with the DuPont Shredded Carpet 30 g kg

-1, the 30 g kg

-1 rates were chosen. Since little data exists for

the

DuPont Shredded Carpet, four rates were chosen. The rates were 5, 10, 20, and 30 g kg

-1.

Plot Construction Field plots were established at the Joseph Valentine Turfgrass

Research Center in University Park, PA, in September of 1995.

The plot area consisted

of an underdrained gravel layer, 150-mm deep, overlaid by a 65-mm intermediate layer. A 100-mm layer

of the sand and sphagnum root zone mix

that was used during

the preliminary testing was installed over the intermediate

layer. The mix was donated by the Fertl-Soil Company, Kennett

Square,PA (Table 1).

A grid of 3.05- by 3.05-m treatment plots was laid over the

level root zone mix. A 300-mm border surrounded each treatment

plot. The

experimental design was a split block (blocks split by three levels of wear) with 12 treatments and three blocks.

All of the treatments (with the exception

of Sportgrass) were weighed and mixed with the root zone mix using a front–end

loader on an asphalt mixing pad. The sand was saturated with

water

during mixing. Wooden frames, 3.05 m by 3.05 m by 150 mm high, were placed on each treatment plot and leveled using

a transit. After filling the

frames with the mixed root zone treatments and allowing the mixture to drain, the surface was

leveled by raking and hand tamping.

The Netlon

treatments were filled to within 15 mm of the surface and 15 mm of the unarmended root zone mix was placed on the surface

of the Netlon/root zone

mixture as per industry recommendations. For the Sportgrass treatment, frames were installed and filled

with the root zone mix to within 25 mm of the

top. The Sportgrass was then cut to fit the frames. Next, small amounts of the root

zone mix was applied over the surface and worked into the pile

with

brooms. The plots were watered and allowed to dry, then more of the mix was broomed into the pile. This process was

repeated until 3 mm of pile

protruded above the settled mix. After the borders were filled with root zone mix, the frames

were removed and plots were seeded with ‘SR 4200’

perennial ryegrass (Lolium perenne L.) at the rate of 200 kg ha

-1. Nutrients and water were applied as needed to prevent

nutritional deficiency and

drought stress. The plot area received five N applications equaling 50 kg N ha

-1 during each growing

season (April–October). The turf was mowed twice

per week with a reel mower at a height of 38 mm and clippings were not

collected in baskets.

Wear level treatments were applied with a Brinkman

Traffic Simulator (Cockerham and Brinkman, 1989). The Brinkman Traffic Simulator

weighs 410 kg and consists of a frame housing two 1.2-m-long

rollers. Each roller has steel dowels or spriggs (12.7-mm diam. by 12.7-mm length) welded to the outside of the rollers, at

an average of 150 dowels m

-

2. These dowels are the approximate

length and width of the cleats on the shoe of an American football

lineman at the collegiate level. The Brinkman

Traffic Simulator produces wear, compaction, and turf/soil lateral shear. The

drive thrust yielding lateral shear is produced by different

sprocket sizes

turning the rollers at unequal speeds. The Brinkman Traffic Simulator was pulled with a model 420 tractor (Steiner

Turf Equipment Inc., Dalton, OH)

equipped with a dual turf tire package. Blocks were split with three levels of wear. The wear levels were no-wear, medium-wear (three passes with theBrinkman Traffic

Simulator three times per week), and high-wear (five passes

three times per week). According to Cockerham and Brinkman (1989),

two passes of the Brinkman Traffic Simulator produces the equivalent number of cleat dents created at the 40-yard line during one

National Football

League game. Thus, 15 passes per week are equivalent to the cleat dents sustained from 7.5 games per week.

In 1996, wear began on 1 June and

ended on 17 October. In 1997, wear began on 2 June and ended 17 October. Typically, wear was

applied regardless of weather conditions or soil

water content. Numerous wear applications occurred when the soil water content

was at or near saturation. Occasionally, due to heavy precipitation

or

schedule conflicts, wear was not applied on the scheduled day. In these cases, wear was applied on the following day.

Data Collection The criteria used for comparing treatments were surface hardness,

soil bulk density, soil water content, and turfgrass density.

Surface hardness was

measured using a Clegg Impact Tester (Lafayette Instrument Company, Lafayette, IN) equipped with a 2.25-kg missile

and a drop height of 440 mm

(Rogers and Waddington, 1989). Impact attenuation, as measured by an accelerometer mounted on the

missile, was used to indicate surface hardness

and is reported as Gmax, which is the ratio of maximum negative acceleration

on impact in units of gravities to the acceleration due to gravity.

The

average of six hardness measurements taken in different locations on each subplot was used to represent the hardness

value of the subplot.

Soil bulk

density data were derived from measurements of soil total density and volumetric water content taken with a Troxler

3400-B Series surface moisture-

density gauge (Troxler Electronic Laboratories, Inc., Research Triangle Park, NC). The Troxler

Gauge uses neutron scattering simultaneously with ray

attenuation to measure the volumetric water content and total density of

the soil (Gardner, 1986). A 150-mm deep guide hole was created

in the soil

using a template and guide rod. A137

Cs source was then inserted into the hole to a depth of 150 mm. The amount

of photons emitted from the source

and reaching the receiver on the surface is a measure of total soil density. Soil bulk density is derived by subtracting the density due to water from thetotal soil density.

Because some reinforcing materials could influence water content

measurements, the Troxler Gauge was calibrated using a Tektronix

1502B time-domain reflectometry (TDR) unit (Tektronix, Inc., Beaverton, OR). To calibrate the Troxler Gauge, water contents

were determined from

each treatment plot, using both the TDR and the Troxler Gauge, on six different occasions to provide

a range of soil water contents. Linear

relationships between the two methods for each reinforcement treatment were evident,

with regression coefficients greater than 0.90).

All water content

values reported in this experiment were collected using the Troxler gauge and then adjusted using the appropriate

regression equation. The values

represent the water content in the surface 150 mm of root zone mix. The adjusted soil water

contents were used to calculate the density due to water

which was subtracted from total density to provide soil bulk density.

Turfgrass density was rated visually and served as an estimate

of number of tillers

per unit area. Density was rated using a scale of 0 to 5 with half units. A plot with no turfgrass

present is rated as 0, and 5 indicates maximum possible

tiller density.

The turfgrass density ratings and the means of the three soil

bulk densities, three soil water contents, and six surface hardness

measurements were analyzed using analysis of variance and Fisher's least significant difference test at the 0.05 level. A LSD was

not calculated when

the F ratio was not significant at the 0.05 level.

Surface Hardness Significant treatment differences for surface hardness were

found on each rating date. Surface hardness of plots

generally increased with increasing

wear levels in both years of the study. Although surface hardness for medium

and high-wear treatments was significantly greater than for

no-wear

treatments on all evaluation dates, actual Gmax values did not differ by >10 units on any date. Surface hardness also

increased as each season

progressed for wear and no-wear treatments. When surface hardness data were averaged across all wear levels,

differences were detected among

reinforcing materials. Generally, surface hardness differences among reinforcing material treatments were greater than differences among wear

treatments. The range of Gmax values for reinforcing material treatments exceeded 20 Gmax units on all rating dates.

Sportgrass had higher surface

hardness values than all other treatments on four of six rating dates and ranged between 28

and 37% higher in surface hardness than the control on

each rating dates. Both rates of Turfgrids and Netlon produced

higher surface hardness values than the control on all rating

dates. When averaged

across all rating dates, the low rates of Netlon and Turfgrids increased surface hardness by 13 and

14%, respectively, when compared with the control,

while the high rates increased surface hardness by an average of 22 and

24%, respectively.

DuPont Shredded Carpet and both Nike treatments usually

produced lower surface hardness values than Sportgrass, Netlon, and Turfgrids. Surface hardness generally decreased as rates of

DuPont Shredded


44/48


Carpet increased from 5 to 30 g kg-1

. When averaged across all rating dates, the 30 g kg

-1 rates of DuPont Shredded

Carpet and Nike Lights produced

surface hardness values that were 10.5 and 12.5% lower than the control, respectively.

Reinforcing material treatment x wear interactions occurred

on

18 Oct. 1996 and on all rating dates in 1997. The interactions indicate that the surface hardness values of some treatments were more strongly

influenced by wear than others. In the case of Sportgrass, surface hardness values for

the high-wear level ranged between 16.5 and 25.4% higher than

the no-wear level on each rating date. Sportgrass consistently measured higher in surface hardness than all other treatments

after wear was applied.

Whereas under no-wear, Sportgrass had surface hardness values similar to the 5 g kg

-1 rates of Netlon

and Turfgrids. DuPont Shredded Carpet 30 g

kg-1

and both Nike treatments responded differently to increasing wear than Sportgrass.

For these treatments, the surface hardness values for the high-

wear level were only 5% higher than the no-wear level when averaged

across all rating dates.

Soil Bulk Density No significant wear x reinforcing material interactions were

detected for bulk density on any of the rating dates in this

study. Bulk density increased with

increasing wear

levels in 1996 and 1997. Also, soil bulk density generally

increased for all wear levels as each growing season progressed.

Soil bulkdensity values ranged from a low of 1.35 g cc

-1 for

the no-wear treatment on 11 June 1997 to 1.47 g cc

-1 for the

high-wear treatment on 15 Oct. 1997.

Increases in bulk density on no-wear plots were presumably due to routine maintenance and foot traffic during data collection.

The drop in bulk

densities for all treatments between 18 Oct. 1996 to 11 June 1997 was likely due to freeze-thaw cycles during

the winter months.

Soil bulk density

values averaged across wear levels revealed differences among the reinforcing material treatments.

The range of bulk density values among

reinforcing material treatments was similar to the range for wear treatments (1.34

g cc

-1 for Nike Lights 30 g kg

-1 on 11 June 1997 to 1.47 g cc

-1for

Netlon 5 g kg-1

on 18 Oct. 1996). The 5 g kg

-1 Netlon treatment produced higher bulk density values

than the control plots on five of six rating dates.

This treatment generally produced higher bulk density values than Sportgrass;

the 10, 20, and 30 g kg

-1 rates of DuPont Shredded Carpet; Nike

Lights

and Heavies; and the 3 g kg-1

rate of Turfgrids. The 3 g kg

-1 Netlon treatment and 3 g kg

-1 Turfgrids treatment typically

did not influence bulk density

relative to the control. The 10, 20, and 30 g kg

-1 rates of DuPont Shredded Carpet lowered

soil bulk density relative to the control on five of six rating

dates. The 5 g kg-1

rate of shredded carpet had no affect on soil bulk density on four of six rating dates. This treatment

resulted in a soil bulk density

that was higher than the control on 23 Aug. 1996 and lower than the control on 15 Oct. 1997.

As with surface hardness, bulk density generally

decreased with increasing rates of DuPont Shredded Carpet. Nike Lights and

Nike Heavies treatments also lowered bulk densities relative

to the control

on five of six rating dates.

Soil Water Content No reinforcing material treatment x wear interactions occurred

in this study with respect to soil water content.

Differences in soil water content were

found among wear levels on four of six rating dates. When differences occurred,

water contents were higher in no-wear and medium-wear treatments

than in high-wear treatments. However, the differences were slight, with an overall variation of only 0.05 m m

-3 across

the duration of the study.

Soil

water contents differed among reinforcing material treatments during both years of the study. Nike Lights 30 g kg-1 and Sportgrass had lower soil watercontents than the control

on five of six rating dates. No other reinforcing material treatment

had a soil water content lower than the control on more than

two of the six rating dates. The only treatments which measured higher in soil water content than the control were Turfgrids

3 g kg

-1 on three rating

dates and all four rates of DuPont Shredded Carpet on one or two rating dates. The range in water

contents during both years of the study was


45/48


The Sportgrass treatment produced the highest surface hardness of any treatment in this test. Surface hardness for this treatment

increased

substantially as wear level increased and as each season progressed. Surface hardness did not appear to be related

to soil bulk density, as there were

no differences in bulk density between the Sportgrass treatment and the control.

The increased surface hardness of the Sportgrass treatment may

have

been the result of an increase in soil strength near the root zone surface. Horizontally-oriented fabrics at or near

the soil surface have dramatically

increased soil strength and load carrying capacity (Gray and Al-Refeai, 1986). Increased

soil surface strength typically results in a higher surface

hardness (Waddington, 1992). The Sportgrass treatment showed a consistent reduction in soil

water content compared with the control throughout the

study. Dryer soil conditions produced by Sportgrass may have resulted

in slightly higher surface hardness. However, the moisture differences

between

the Sportgrass treatment and the control were only 0.02 to 0.03 m m

-3, and probably not enough to account for the large

differences in surface

hardness.

CONCLUSIONS Overall, the greatest impact of reinforcing materials subjected to different wear levels in a sand root zone was on surface hardness. This is potentiallysignificant because increased

surface hardness of an athletic field results in a greater risk

of athlete injury in the event of a fall (Baker and Canaway,

1993). Conclusions and recommendations based on surface hardness

data from the present study are difficult to formulate because

no recognized

standards currently exist for acceptable surface hardness values of athletic fields as measured by the Clegg

Impact Tester. In an attempt to relate

surface hardness to athlete performance and safety, Canaway et al. (1990) correlated athletic

field surface hardness measurements with athlete's

perceptions of surface hardness. On the basis of hardness values obtained

with the Clegg Impact Tester and a 0.5-kg missle, Canaway et al. (1990)

suggested a preferred upper limit of 80 Gmax. A 2.25-kg missile was used in the present study and has been shown to

produce lower Gmax values

compared with the 0.5-kg missile (Rogers and Waddington, 1990). Rogers and Waddington (1990) reported

that the 0.5-kg missile will typically record

Gmax values that are 24 to 50 units higher than values produced by the 2.25-kg

missile. Using this comparison, Sportgrass, Netlon 5 g kg

-1, and

Turfgrids 5 g kg-1

reinforcing material treatments resulted in hardness values that were probably greater than the preferred

upper limit suggested by

Canaway et al. (1990). Athletic field managers considering the use of soil reinforcing

materials should be aware that if a field is exposed to high

wear,

Netlon and Turfgrids at the 5 g kg-1

rate and Sportgrass have the potential to exceed the preferred upper surface hardness

limit suggested by Canaway

et al. (1990). The high rates of DuPont Shredded Carpet and Nike Lights consistently resulted

in surface hardness values lower than the control, even

under high wear, and may be less likely to result in athlete injury

during player/surface impacts.

REFERENCES• American Society for Testing and Materials. 1997. Annual Book of ASTM Standards. Vol. 15.07. End Use Products. Standard test method for

saturated hydraulic conductivity, water retention, porosity, particle density, and bulk density of putting green and sports turf rootzone mixes.F1815–97. ASTM, West Conshohocken, PA.

• American Society for Testing and Materials. 1998. Annual Book of ASTM Standards. Vol. 15.07. End Use Products. Standard test method fororganic matter content of putting green and sports turf rootzone mixes. F1647–98. ASTM, West Conshohocken, PA.

• American Society for Testing and Materials. 1999. Annual Book of ASTM Standards. Vol. 4.08. Soil and Rock. Test method for laboratorycompaction characteristics of soil using standard effort. D698–91. ASTM, West Conshohocken, PA.

• Baker, S.W. 1991. Temporal variation of selected mechanical properties of natural turf football pitches. J. Sports Turf Res. Inst. 67:83–92.

• Baker, S.W. 1997. The reinforcement of turfgrass areas using plastic and other synthetic materials: A review. Int. Turf. Soc. Res. J. 8:3–13.

• Baker, S.W., and P.M. Canaway. 1993. Concepts of playing quality: Criteria and measurement. Int. Turf. Soc. Res. J. 7:172–181.

• Baker, S.W., and C.W. Richards. 1995. The effect of fibre reinforcement on the quality of sand rootzones used for winter games pitches. J. SportsTurf Res. Inst. 71:107–117.

• Beard, J.B., and S.I. Sifers. 1993. Stabilization and enhancement of sand-modified rootzones for high traffic sports turfs with mesh elements. Arandomly interlocking me

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