Browsing by Author "James, Iain T."

Now showing 1 - 4 of 4
  • Thumbnail Image
    ItemOpen Access
    Are golf courses a source or sink of atmospheric CO2: A modelling approach
    (Professional Engineering Publishing, 2011-06-01T00:00:00Z) Bartlett, M. D.; James, Iain T.
    Sports facilities have been shown to have a positive impact on local biodiversity, quality of life and the economy. Their impact on global carbon balances is less clearly understood. Increased concentrations of atmospheric CO2 have been linked with global climate change. Currently there is debate as to whether amenity turf is a net source or a net sink for atmospheric CO2. The turfgrass of a natural sports pitch will sequester carbon through photosynthesis, but there are numerous emission sources associated with the management of turf which release CO2 into the atmosphere. These include the engines used to power mechanised operations such as mowing and spraying, the application of agrochemicals, including fertilizers, and the disposal of waste. In order to determine if a real-world example of a sports facility was a source or sink of carbon a mechanistic mass balance model was developed. Analysis indicated that, the areas of the golf course that received the most management attention were a net source of carbon emissions. The magnitude of these releases was significantly different on an equal area basis (p<0.01). The net carbon budget for turfgrass areas across the whole golf course, accounting for the sequestration by the turfgrass was -44.1 g C m-2 y-1. The mature trees that formed an integral part of the landscape of the modelled course had a significant impact on the net carbon balance, resulting in overall net sequestration of -145.4 Mg C y-1 for the whole golf course, equivalent to -1.48 Mg C ha-1 y-1. The variability in the size, shape and vegetation composition of different golf courses has a considerable impact on their net carbon balance, and the resultant environmental impact of sports facilities must be assessed on an individual basis.
  • Thumbnail Image
    ItemOpen Access
    Development of a Simplified Dynamic Testing Device for Turfed Sports Surfaces
    (Professional Engineering Publishing, 2011-06-01T00:00:00Z) Caple, Matt C. J.; James, Iain T.; Bartlett, Mark D.; Bartlett, David I.
    The response of natural turf surfaces to loading changes with the force and loading rate applied. Quantification of surface behaviour to athlete loading is complicated by the lack of devices that replicate forces, stresses and loading rates of athletes that can be specifically used on natural turf. To address this issue, a vertical dynamic impact testing device, the DST, was developed. The DST consists of a compressed air driven ram which vertically impacts a studded test foot onto the surface using data from biomechanical studies. The vertical dynamic stress of athlete foot strike during running is replicated, using peak force and mean boot contact area data. The ram pressure is adjustable to allow variation of the stress applied upon impact, potentially replicating a range of athlete-surface interactions. Initial laboratory testing indicated that the device was sensitive to changes in soil condition due to variations in impact data. Total penetration time and distance, and surface energy absorption were all significantly greater in prepared ‘soft' soil treatments (p<0.05). Loading rate in the first 50 ms after impact was significantly greater in the ‘hardest' soil treatment (p<0.05). Future research work will determine in-situ behaviour of actual playing surfaces, compare device loading rates to those of athletes, and assess surfaces to a range of stres
  • Thumbnail Image
    ItemOpen Access
    The effect of maintenance on the performance of sand-filled synthetic turf surfaces
    (2010-09-27T00:00:00Z) James, Iain T.; McLeod, Andrew J.
    The effect of infill quantity and contamination on the performance of second generation sand-filled synthetic turf sports surfaces was investigated in a laboratory study. Three 1m2 test surfaces were constructed by placing synthetic turf over a stone-tar-macadam-rubber shockpad sub-base. Ball rebound, ball roll, surface rebound hardness and rotational resistance of a dimpled rubber sole were measured for a range of infill quantities (0-35 kg/m2) and infill contamination concentrations (0, 10 and 20%). Increasing infill quantity increased hardness, reduced ball rebound and reduced rotational resistance linearly (p , 0.01). Ball deceleration increased up to 10 kg/m2 after which there was no further significant increase in the range tested. An optimum infill quantity of 25-30 kg/m2, based on performance characteristics and the length of fibre above the infill, was identified for the synthetic turf surface tested. Increasing contamination also increased ball deceleration and reduced infiltration rate and kept surfaces wetter for longer during drying (p , 0.001), resulting in conditions suitable for moss and algae formation. Maintenance, including regular brushing and monitoring of infill quantity, is required to ensure even distribution of the correct quantity of infill and the minimization of infill contamination in all infilled synthetic turf surfaces.
  • Thumbnail Image
    ItemOpen Access
    Soil Factors and their Influence on Within-Field Crop Variability, I: Field Observation of Soil Variation
    (Elsevier Science B.V., Amsterdam, 2003-04-01T00:00:00Z) Earl, R.; Taylor, John C.; Wood, G. A.; Bradley, I.; James, Iain T.; Waine, Toby W.; Welsh, J. P.; Godwin, R. J.; Knight, S. M.
    A fundamental component of adopting the concept of precision farming in practice is the ability to measure spatial variation in soil factors and assess the influence of this on crop variability in order to apply appropriate management strategies. The aim of this study was to appraise potential methods for measuring spatial variability in soil type, nutrient status and physical properties in practical farming situations. Five fields that are representative of more than 30% of soils used for arable production in England and Wales were selected for use as case studies. Maps of soil type were generated from a conventional hand auger survey on a 100 m grid and the excavation of targeted soil profile pits. These were compared with those refined using a mechanised soil coring device and scans of electromagnetic inductance (EMI) carried out while the soil could reasonably be considered to be at, or near, field capacity moisture content. In addition, soil sampling for nutrient analyses was conducted on a 50 m grid to examine the spatial variation in nutrient status. Conventional methods for sampling soil were found to be appropriate for identifying soil types at specific locations within the field sites, however, they were time- consuming to perform which placed an economic and therefore a practical limitation on the sampling density possible. The resulting data were considered to be too sparse for demarcating soil type boundaries for use in the context of precision farming. The location of soil boundaries were refined by using the mechanised soil corer, however, the limitation of this was found to be the time required to analyse the soil cores produced. Maps of soil variation generated from EMI scans conducted at field capacity appear to reflect the underlying variation in soil type observed in maps generated using the mechanised soil corer. and, therefore, this approach has potential as a cost-effective, data- rich, surrogate for measures of soil variability. Results from analyses of soil samples for measurement of nutrient status indicated that whilst there was considerable variation in macro- and micro-nutrient levels in each field, with the exception of pH, these levels were above commonly accepted agronomic limits. Results did however demonstrate the potential for addressing variation in critical factors such as pH at specific locations, however, there is a need to develop protocols for targeting sampling in order to reduce costs.