Colin Mumford THE OPTIMIZATION OF GOING MANAGEMENT ON UK RACECOURSES USING CONTROLLED WATER APPLICATIONS Doctor of Engineering Cranfield University at Silsoe National Soil Resources Institute Doctor of Engineering Academic Year 2006 / 2007 Colin Mumford THE OPTIMIZATION OF GOING MANAGEMENT ON UK RACECOURSES USING CONTROLLED WATER APPLICATIONS Supervisor: Alex Vickers December 2006 This thesis is submitted in partial fulfilment of the requirements for the degree of Doctor of Engineering © Cranfield University, 2006. All rights reserved. No part of this publication may be reproduced without the written permission of the copyright holder. Abstract Non-uniform surface rating (going) on a racecourse increases the potential for risk of injury to competing horses and their riders. Variability in soil type and strength are the primary cause of inconsistent going. This research aimed to produce guidelines for Racecourse Managers to help them achieve uniform going by influencing the strength of the different soil types encountered on a racecourse using controlled water applications. Two models were developed, a soil-water balance to predict the mean going for a given soil type (MEGPREM), and a determination of effective irrigation model (DEFFIM) that establishes how much water is required to change a hard level of going to a preferred softer level. MEGPREM was found to provide poor predictions of going. DEFFIM was shown to be a valid model, and potentially provides Racecourse Managers with a useful tool to aid their decision making with regards to watering. A further study to determine whether different irrigation regimes affected the structure of two different soil types concluded that a regime that allows the soil to dry to a pre- determined soil-water deficit and then re-wet to field capacity produced better soil physical properties than soils maintained at field capacity. Utilizing a simulated irrigation regime, directed by DEFFIM, that achieved wet/dry cycles as described, a cost analysis was carried out to compare the simulated irrigation with the actual irrigation practices at a racecourse for the 2004 and 2005 flat racing seasons. The results suggested that potentially significant savings in water consumption could be achieved with the use of DEFFIM, satisfying the requirements of the Water Act 2003, whilst still maintaining a preferred level of going. The findings of this research suggest that going management on a racecourse could be optimized with controlled water applications, potentially reducing the risk of injury to competing horses and jockeys. i EngD Thesis 2006 List of Contents Section Page No. 1.0. Introduction…………………………………………………………………... 1 1.1. Aims of the research project………………………………………………. 3 1.1.1. Objectives…………………………………………………………… 3 1.2. Statement of approach...…………………………………………………… 4 2.0. Literature Review………...………………………………………………….. 6 2.1. Horse injuries……………………………………………………………… 6 2.2. Determining the rating of a racecourse’s surface conditions……………… 9 2.2.1. Subjective measurements of going………………………………….. 10 2.2.2. Objective measurements of going…………………………………… 11 2.2.3. Potential impact of incorrect going determinations…………………. 14 2.3. Management issues………………………………………………………... 15 2.3.1. Turfgrass…………………………………………………………….. 17 2.3.1.1. Thatch accumulation…………………………………………... 18 2.3.1.2. Root growth…………………………………………………… 18 2.3.2. Soil texture…………………………………………………………... 20 2.3.3. Soil structure………………………………………………………… 22 2.3.3.1. Shrink-swell cycles……………………………………………. 23 2.3.3.2. Soil compaction……………………………………………….. 24 2.3.4. Soil strength…………………………………………………………. 25 2.3.4.1. Soil water release characteristics……………………………… 26 2.3.4.2. Hysterisis……………………………………………………… 27 2.3.4.3. Atterberg limits………………………………………………... 28 2.3.5. Determination of water loss from the surface……………………….. 30 2.3.5.1. Establishing ET rates for racecourse turfgrass………………… 30 2.3.5.2. Determination of reference crop ET (ETo) for racecourse turfgrass…………………………………………… 32 2.3.5.3. Determination of actual ET (ETc) for racecourse turfgrass……. 32 2.3.5.4. Determination of crop coefficient (Kc) for racecourse turfgrass…………………………………………… 33 2.3.5.5. Irrigation………………………………………………………. 35 2.4. Environmental Regulation………………………………………………… 37 2.4.1. The impact of the Water Act 2003 on water use on racecourses……. 37 2.4.2. The Porter hypothesis……………………………………………….. 38 2.4.3. Technologies available to racecourses to improve irrigation strategies………………………………………………….. 39 2.4.3.1. Weather stations………………………………………………. 39 2.4.3.2. Soil moisture sensors………………………………………….. 40 2.4.3.3. Computer software…………………………………………….. 40 2.4.3.4. Valve in head sprinkler control………………………………... 40 2.4.3.5. Travelling boom……………………………………………….. 41 2.4.3.6. Variable valve control…………………………………………. 41 ii EngD Thesis 2006 List of Contents Section Page No. 2.4.4. Acceptance of technology in the racecourse industry………………..41 2.4.5. Porters hypothesis in relation to racecourses………………………... 42 2.5. Summary of the Literature………………………………………………… 42 2.6. Conclusions………………………………………………………………... 43 3.0. Contextual Framework of the Experimental Programme………………… 45 3.1. Potential soil moisture deficit……………………………………………... 45 3.1.1. Agroclimatic zones of racecourses………………………………….. 47 3.1.2. Discussion of the results of the potential soil moisture deficit for each racecourse…………………………………………... 49 3.2. Questionnaire survey……………………………………………………… 49 3.2.1. Analysis of questionnaire data………………………………………. 50 3.3. Questionnaire survey results………………………………………………. 51 3.3.1. Predominant soil type……………………………………………….. 51 3.3.2. Grass species………………………………………………………… 52 3.3.2.1. Influence of soil texture on sward composition……………….. 52 3.3.3. Irrigation of the racecourse………………………………………….. 53 3.3.3.1. Determination of irrigation requirement………………………. 53 3.3.3.2. Sources of water and method of application…………………... 53 3.3.3.3. Irrigation use in 2001………………………………………….. 55 3.3.3.4. Influence of soil texture on water use…………………………. 58 3.3.4. Cancelled race days…………………………………………………..58 3.4. Discussion of the results of the questionnaire survey……………………... 59 3.4.1. Predominant soil type……………………………………………….. 60 3.4.2. Grass species………………………………………………………… 60 3.4.2.1. Influence of soil texture on sward composition……………….. 60 3.4.3. Irrigation of the racecourse………………………………………….. 61 3.4.3.1. Determination of irrigation requirements……………………... 61 3.4.3.2. Sources of water and method of application…………………... 62 3.4.3.3. Irrigation use in 2001………………………………………….. 62 3.4.3.4. Influence of soil type on water use……………………………. 63 3.4.4. Cancelled race days…………………………………………………. 64 3.4.5. Limitations of the questionnaire survey……………………………... 64 3.5. Conclusions………………………………………………………………... 65 4.0. Audit of Eight Racecourses………………………………………………….. 66 4.1. Identification of eight racecourses for further research…………………… 66 4.1.1. Selected racecourses for further analysis……………………………. 67 4.2. Methodology of the audit of eight selected racecourses…………………... 68 4.2.1. Particle size distribution analysis……………………………………. 69 4.2.2. Dry bulk density analysis……………………………………………. 69 4.2.3. Soil penetrative resistance…………………………………………… 69 4.2.4. Analysis of results…………………………………………………… 69 4.3. Results of the audit of eight racecourses…………………………………... 70 iii EngD Thesis 2006 List of Contents Section Page No. 4.3.1. Soil textural classification…………………………………………… 70 4.3.2. Soil dry bulk density………………………………………………… 72 4.3.3. Soil penetrative resistance (SPR)……………………………………. 73 4.4. Discussion of the results of the audit of eight racecourses………………... 75 4.4.1. Selection of the eight racecourses for further analysis……………… 75 4.4.2. Audit of eight selected racecourses…………………………………. 75 4.4.3. Soil textural classification…………………………………………… 75 4.4.4. Dry bulk density…………………………………………………….. 76 4.4.5. Soil penetrative resistance…………………………………………… 77 4.5. Conclusions to the audit of eight racecourses……………………………... 78 4.6. Selection of two racecourses for further research: criteria for selection….. 79 4.6.1. Selected racecourses for further study………………………………. 79 4.6.2. Discussion of the selection of two racecourses for further study…… 80 5.0. Validation of the Going-Stick……………………………………………….. 81 5.1. Methodology………………………………………………………………. 81 5.1.1. Going-Stick penetration and shear repeatability test………………... 81 5.1.2. Going-Stick comparison test………………………………………… 82 5.1.3. Determination of the relationship between Going-Stick values and volumetric soil moisture content………………………… 83 5.1.4. Analysis……………………………………………………………... 83 5.2. Results……………………………………………………………………... 84 5.2.1. Going-Stick penetration and shear repeatability test………………... 84 5.2.2. Going-Stick comparison test…………………………………..…….. 85 5.2.2.1. Going………………………………………………………….. 85 5.2.2.2. Dry bulk density……………………………………………….. 86 5.2.2.3. Penetration…………………………………………………….. 88 5.2.3. Determination of the relationship between Going-Stick values and volumetric soil moisture content………………………… 88 5.3. Summary of going-stick validity tests…………………………………….. 90 6.0. Modelling Going using a Soil Water Balance: Development, Calibration and Validation………………………………………………………………... 91 6.1. Soil-water balance modelling……………………………………………... 92 6.1.1. Simple soil-water balance model requirements……………………... 92 6.1.2. Determination of reference crop evapotranspiration………………... 93 6.1.3. Adjustment of the reference crop evapotranspiration to an actual evapotranspiration……………………………………… 95 6.1.4. Calculating a soil-water deficit……………………………………… 95 6.1.5. Rainfall balance model………………………………………………