Advancing Natural Turf to Meet Tomorrow's Challenges
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Advancing natural turf to meet tomorrow’s Dr Iain James challenges Senior Lecturer Centre for Sports Surface Technology Cranfield University What do we think of when we think ‘natural turf’? Golf The Wisley Golf Club, Surrey, UK Football Melbourne Cricket Ground, Melbourne Tennis All England Lawn Tennis Club, Wimbledon, London Natural turf in the news... The Guardian, 7 November 2009 Wembley Attendance: 47,106 Average attendance in Guinness Premiership on same weekend: 10,262 ± 1140 The Sun, 19 April 2010 Not just elite sport Natural Turf Performance • Ambience and aesthetic quality • Sport performance • ball-surface interactions • player-surface interactions • Durability • Environmental and financial sustainability (increasingly) Delivering quality Level Elite Quality Resource consumption Revenue generation Attention Quantity, Participation, Environmental benefit Rec. Challenges for natural turf • Deliver quality surfaces in poor environments • Deliver flexibility for stadia • Deliver safe, high quality surfaces with insufficient resources • Deliver quality surfaces with reduced resources • Deliver surfaces that look good on HD TV The natural turf system Understanding the system enables delivery of quality... (...or an explanation of why quality isn’t delivered) The natural turf system (simplified) CO2/O2 O2/CO2 Light H2O Structural support O2 H2O CO2 Plant nutrients Soil matrix 20-30% ‘Air’ 45% Mineral 30-20% ‘Water’ 5% Organic Matter www.cranfield.ac.uk/sas/sst/rolling Source: Shipton and James (2009) ECB Cranfield Guidelines for Rolling in Cricket. porosity Compaction and Moisture Content 20% 30% 1.40 g/cm 3 Dry Bulk Density 1.65 g/cm 3 1.80 g/cm 3 Soil particle size Clay Silt Fine Sand Medium Sand Coarse Sand Soil types Cricket Pitch, Eden Park, Auckland3 Cricket Pitch, WACA, Perth1 Cricket Pitch, AMI Stadium (Lancaster Park), Christchurch3 Cricket Pitch, SCG, Sydney2 Cranfield University Football Pitch Uttoxeter Racecourse, UK5 Cricket Pitch, Port of Spain, Trinidad4 Fairway, Woburn Golf Course6 Fairway, Wisley Golf Cricket Pitch, Lord’s, London Course Stadium sand-construction Lingfield Park Racecourse, football pitches UK5 e.g. Wembley, Arsenal USGA Specification Golf Green7 Outfield, Lord’s Cricket Ground, London Leicester Racecourse, UK5 8 Sandown Park Racecourse, UK5 Tennis Court, Wimbledon, London Rugby Pitch, Eden Park, Auckland Construction materials So why construct from sand? Hydraulic conductivity / Infiltration Soil type Saturated hydraulic rate conductivity Beach sand 360 mm/h Very sandy soil 180 mm/h Field (agricultural) soil 18 mm/h Irrigation water Compacted clay soil < 3.6 x 10-4 mm/h Source: Brady & Weil, Nature and Properties of Soil 13th ed. USGA Specification golf green: >150 mm/h Standard Infiltration rate FIFA 1* or 2* >180 mm/h DIN 18035/4 for >60 mm/h natural turf FA Performance >5 mm/h Quality Standard Typical CEC values for sports turf soils Fertiliser quantity Soil texture Cation exchange capacity (cmol kg-1) Sand (1-2% OM) 1-3 Sand (2-4% OM) 3-5 Sandy loam 3-10 Loam 7-16 Silt loam 10-25 Clay (2:1 mineralogy) 20-50 Clay (1:1 mineralogy) 4-6 Source: Carrow et al., 2001. Turfgrass Soil Fertility and Chemical Problems The natural turf system (simplified) CO2/O2 O2/CO2 Light H2O Irrigation quantity Structural support O2 H2O CO2 Plant Fertiliser quantity nutrients Mechanical testing of sports soils used for natural turf sportsGuisasola surfaces. IN, James Sports IT, Engineering Llewellyn 12:99-109 CA, Stiles VH, Dixon SJ (2010a). Quasi-static mechanical behaviour of soils soils testing of sports Mechanical Deviatoric stress (q), kN m -2 200 400 600 800 0 0 5 Axial strain ( 10 Sand (a) 15 a ), % 20 S3 S2 S1 25 Deviatoric stress (q), kN m -2 200 400 600 800 0 0 5 Axial strain ( Clay Loam 10 (b) 15 a ), % 20 C3 C2 C1 25 used for natural turf sportsGuisasola surfaces. IN, James Sports IT, Engineering Llewellyn 12:99-109 CA, Stiles VH, Dixon SJ (2010a). Quasi-static mechanical behaviour of soils content strength to water Sensitivity of shear Deviatoric yield stress kN m-2 (@ 100 kPa confining stress) 100 150 200 250 300 50 0 0.1 0.3 0.5 0.7 0.9 Saturation ratio Clay Loam Sand Tracking movement Courtesy of Vicky Stiles and Sharon Dixon at University of Exeter Stiles VH, Dixon SJ, James IT (2006). An initial investigation of Human-Natural Turf Interaction in the Laboratory Running on natural turf Fy, BW -1.5 -1.0 -0.5 0 0.5 1.0 1.5 3.0 0 B F 2.5 z A -0.5 Fy 2.0 -1.0 W W B 1.5 , B e -1.5 , c z r 1.0 F o C F -2.0 0.5 A 0 C -2.5 B -0.5 -3.0 0 0.1 0.2 0.3 Time, s 0.00 s 0.00 s 0.00 s 0.10 s 0.10 s 0.10 s 0.20 s 0.20 s 0.20 s 50 mm 50 mm 50 mm A(c) (d)B (e)C Cyclic dynamic loading 2 N k , 1 z F 0 0 1 2 3 4 5 6 7 8 9 10 Axial displacement (z), mm Engineering 12:111-112 turf sports surfaces. Sports behaviour of soils used forDixon natural SJ (2010b). Dynamic Guisasola IN, James IT, Stiles VH, dependent behaviour – rate Visco elastic Axial stress, kN m-2 Axial stress, kN m-2 Axial stress, kN m-2 100 200 300 400 500 100 200 300 400 500 100 200 300 400 500 0 0 0 0 0 0 0.01 0.01 0.01 0.02 0.02 0.02 C1 0.62 kN s C2 0.61 kN s S2 0.63 kN s Axial strain Axial strain Axial strain 0.03 0.03 0.03 -1 -1 -1 0.04 0.04 0.04 Last cycle First cycle 0.05 0.05 0.05 Axial stress, kN m-2 Axial stress, kN m-2 Axial stress, kN m-2 100 200 300 400 500 100 200 300 400 500 100 200 300 400 500 0 0 0 0 0 0 0.01 0.01 0.01 0.02 0.02 0.02 C1 5.70 kN s C2 5.72 kN s S2 5.87 kN s Axial strain Axial strain Axial strain 0.03 0.03 0.03 -1 -1 -1 0.04 0.04 0.04 0.05 0.05 0.05 on root volume Effect of mowing 50 mm The natural turf system (simplified) CO2/O2 O2/CO2 Light H2O Irrigation quantity Structural support O2 H2O CO2 Compromised Plant Fertiliser quantity root system nutrients Managing turf in stadia Can we really finish the system off? The natural turf system (simplified) CO2/O2 O2/CO2 Air quality Light Light quality/quantity H2O Irrigation quantity Structural support O2 H2O CO2 Compromised Plant Fertiliser quantity root system nutrients Shade problems July 2008, Docklands Stadium, Melbourne Shade problems Emirates stadium by night Plant breeding Penn State Turfgrass Breeding Trial, Pennsylvania USA Courtesy of Mark Bartlett Reinforcing rootzones Fibresand (e.g. Lord’s, Wembley) Netlon / StrathAyr Reinforcing rootzones Desso GrassMaster (Arsenal, MK Dons etc) Motz TS11 (Eden Park, MCG) Aim: to provide flexibility for venues Recreational sport facilities Challenges... Limited carrying capacity Standard soil pitch with pipe drainage = 1-3 h/week Sand slitted pitch = 3-5 h/week Baker SW, Gibbs RJ, Adams WA (1991). Making the most of natural turf pitches. Final results of a case studies approach. II. Playing quality. Natural Turf Pitches Prototypes Advisory Panel Report No. 7. Sports Council, London, UK. Challenges for recreational level sport • Limited maintenance budgets • Sand slit system: £30-40 k /pitch • Topdressing: £3k /pitch /year • Restricted resource use • Water restrictions in San Diego metropolitan area 12 min of irrigation per week & $2 ft2 tax rebate for synthetic turf • Nitrogen fertiliser application: 1% N2O emission (N2O= 298 CO2e) • Reduction of pesticide exposure Concerns of safety and liability A L L E T A Surgery & consultations £ 4950 P Post-op physiotherapy £ 1050 Work time lost pre-op £ 2400 Work time lost post-op £ 3200 Sundries £ 57 Lost future earnings £ 0 from playing rugby Total £ 11,657 Synthetic turf solution • Synthetic turf is part of the solution, but not all of it: • Natural turf remains the only viable surface for some sports due to £/ha of synthetic turf • Playing requirements for some sports dictate natural turf? Challenges for the future... Challenges for the future (1) • Need to increase hours of use whilst reducing resource consumption for natural turf (improved sustainability) • Water footprint of 1m3 per round of golf in Spain • Carbon footprint of 400 g CO2e per round in UK • Solution: • Improved water use efficiency • Grass breeding (drought, wear and pest resistance + reduced mowing) • Soil amendment • Rootzone design (less sand, less water, less fertiliser) Challenges for the future (2) • Need improved understanding of injury on natural turf • Solution: • Further study of player-surface interaction • Epidemiology studies • Improved (relevant) characterisation of surfaces Challenges for the future (3) • Improved resilience to a changing climate • Solution: • Research into mitigation and to improve resilience • Understanding the role of sports surfaces in flood prevention • Improved facilities strategies at national level • Improved education Conclusion • The modern sports surface is a huge improvement on those of 20-30 years ago. • Unsustainable solution for all but a small percentage of sports facilities in the future • The modern natural turf surface is vulnerable and not the final answer – further work required (plenty of evidence to support this). Thank you for listening www.cranfield.ac.uk/sas/sst [email protected].