Technical
be carried out. Compatible loams will hold together at a greater applied pressure, i.e. they are stronger. Where loams may be incompatible, they will separate at the interface between the combined materials, often at a lower applied pressure. I found it useful to run some standard ASSB tests on motties made from a single loam to give strength data for comparison with the composite motties.
Cricket Loam Constituents:
Clay content is rightly the first constituent part to be considered when selecting a cricket loam for compatibility. Clay content of a cricket loam typically accounts for around 25-35% of the loam material, yet it confers many of the most important characteristics required for cricket pitch performance. Once wetted, it is the plasticity of the clay that
allows it to be worked with a smooth roller into a surface suitable for cricket. Upon drying, clay gives the loam its strength, which is a requirement for good consistent pace and bounce. In my research project, clay content by far had the most significant effect on strength of the composite motties. If selecting a replacement loam for performance
issues associated with improved pace and bounce, and working on the assumption that you have a homogeneous square profile to which to add a new loam, it would seem sensible to look for an increase in clay content. However, it is short sighted to select compatible loams on clay content alone. We know that all of the loam constituents have some bearing on strength of a cricket loam. It is the broad range of particle sizes in cricket loams that allow for increasing degrees of particle inter-packing and higher bulk density; think the opposite of a uniformly distributed USGA golf putting green rootzone. When considering that the silt and sand fraction may account for as much as three quarters of the loam material, it seems obvious that they must have some influence on a cricket loams performance. Interestingly, silt has been shown to be negatively
correlated with strength when considered alongside clay whilst, conversely, sand has been positively correlated with strength. In either case, it would seem that it is the interaction with the clay fraction, overall clay content and the overall range of particle size (including silt and sand) that is critical in determining strength. When considering shrinkage of a cricket loam clay
content and, to a lesser extent, clay mineralogy should be considered. Two materials with vastly different clay contents will likely shrink at different rates. Mineralogy is less of an issue with many of the commercially available loams, having a similar mineral make-up of the clay fraction. Of the loams I tested, there was only one notable exception with an obviously differing mineralogy; however, mineralogy was not shown to have a significant effect on either strength or shrinkage. Silt content and sand content have been shown to
effect cricket loam shrinkage rates. It is possible that an increased amount of smaller silt and clay particles allows for a greater degree of particle inter-packing
on contraction of the soil when drying although, without external compaction forces, it is not clear how this particle reorganisation would take place. It is perhaps more likely that water held in mesopores (medium-sized pores) and around the silt particles evaporates as the motty dries, causing greater shrinkage. Of the five loams tested, all had organic matter
contents between 2-8%, which is the ECB recommended guideline for organic matter in topdressings. Organic matter is known to absorb water, deaden ball bounce and reduce soil binding strength but, in the quantities seen in the research, it was not thought as much of an issue as surface accumulations. This brings to the fore the need to clean a surface thoroughly before applying a topdressing, possibly even more important if introducing a new loam to the square.
Summary:
Ideally, one would continue to topdress a cricket square with the loam with which it was constructed. In the eventuality that a change of loams is required, it is prudent to carry out some simple tests to ascertain the suitability of a compatible material. One thing for sure is that all of the loam
constituents must be considered when selecting a loam for compatibility. Unless changing loam for performance issues, it would seem sensible to match as closely as possible all of the constituent parts or, put another way, match the particle size distribution. Things change a bit if looking for higher clay
content loams but, again, some consideration should also be given to the silt and sand contents and how the constituents interact and the rate at which shrinkage occurs. As stated before, differing shrinkage rates between layered materials can lead to horizontal fissures at the interface between those materials which, upon drying, can cause variable and slow and/or low bounce. Such an outcome would be counterproductive if the aim is to improve pitch performance. The interactions between the various constituent
parts of cricket loams are potentially complex and this article only offers a brief overview of the subject. It does, however, make the point that if you were in any doubt at all; all constituent parts of a cricket loam exert some effect on its behaviour and must be considered as part of the selection process for a compatible material.
- Only topdress with compatible cricket loams
- Carry out a modified ASSB test to ascertain compatibility between loams
- Strength is important, but matching shrinkage rates is absolutely key to compatibility
- All constituents of a cricket loam must be considered when selecting cricket loams for compatibility
Daniel’s research project was the culmination of five years of online study. The BSc (Hons.) Sports Turf Science and Management was studied online with Myerscough College over two years, following the completion of the FdSc Sports Turf Science, which was studied online over three years.
Prepared composite motties - composed of two halves of different loams
Further Reading:
Adams W. A. & Gibbs R. J. 1994. Natural Turf for Sport and Amenity: Science and Practice. Cab International.
Adams W.A. Baker S.W. Carre M.J. Young R.J. & James D.M. 2004. Pitch Properties and Performance. England and Wales Cricket Board.
Baker S. W. Cook. A & Adams W. A. 1998. Soil Characteristics of First Class Cricket Pitches and Their Influence on Playing Performance. Journal of Turfgrass Science Vol. 74
Baker S. W. Cook A. & Binns D. J. 1998. The Effect of Soil Type and Profile Construction on the Performance of Cricket Pitches. I. Soil Properties and Grass Cover During the First Season of Use. Journal of Turfgrass Science Vol. 74
Baker S. W. Cook A. Binns D. J. Carre M. J. & Haake S. J. 1998. The Effect of Soil Type and Profile Construction on the Performance of Cricket Pitches. II. Playing Quality During the First Season Use Journal of Turfgrass Science Vol. 74
Baker S.W. Hammond L.K.F. Owen A.G. & Adams W.A. 2003. Soil Physical Properties of First Class Cricket Pitches in England and Wales. I. Classification for Soil Characteristics. Journal of Turfgrass and Sports Surface Science Vol. 79.
Baker S.W. Hammond L.K.F. Owen A.G. & Adams W.A. 2003. Soil Physical Properties of First Class Cricket Pitches in England and Wales. II. Influence of Soil Type and Pitch Preparation on Playing Quality. Journal of Turfgrass and Sports Surface Science Vol. 79.
ECB 2011. Recommended Guidelines for the Construction, Preparation and Maintenance of Cricket Pitches and Outfields at all Levels of the Game. TS4. ECB.
Leach A. 2009. Beyond Clay Contents for Cricket Loams: The effect of Silt and Sand. Cranfield University. School of Applied Science. Department for Natural Resources.
Lewis A. 2006. The Shrink and Swell Characteristics of Clay Loams Used for Cricket Pitches. Cranfield University. The National Soil Resources Institute. Department of Sports Surface Technology.
Well Graded Poorly Graded
Soil Particle Size and structure - well graded (broad range of particle size) and poorly graded (uniform range of particle size)
Normal profile Root break
Graphic clearly showing the effect of root break on the grass roots
Shipton P. 2008. Optimisation of Cricket Pitch Rolling. Cranfield University. School of Applied Sciences. Natural Resources Department
Stewart V.I. 1994. Sports Turf: Science, Construction and Maintenance. 1st ed. E & FN Spon.
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