What are cricket wicket soils?

May 31|Natural TurfBy SPORTENG

Cricket wicket soils represent the most challenging of soils from a turf agronomy perspective and are characterised by being:

  • Very fine textured with a high clay content.
  • Highly susceptible to compaction.
  • Very slow draining.
  • Very plastic and can be moulded when at a high moisture content.
  • Will often crack and crumble as it dries out.

A soil that compacts and has a slow infiltration/drainage rate is usually undesirable for good turf growth. However, compaction and hardness are the most desirable characteristics for high performance cricket wickets. The fact that cricket wicket soils crack on drying helps to restore porosity, aeration and drainage which in turn assists in grass regeneration after a pitch is used for a cricket match.

The selection of the clay soil for cricket wickets is the single most important decision in wicket block construction.

What are the ideal characteristics for cricket wicket soils?

Over the past 35 years the selection of cricket wicket soils has been an ongoing point of discussion amongst cricket wicket curators, particularly as many of the traditional sources became depleted.

In Australia, the earliest written reference of using cricket soil (“black soil and manure”) dates from the late 1850’s in Victoria with the earliest published study of Australian cricket wicket soils dating back to the early 1930’s (Beehag, 2019). This highlights that the importance of selecting an appropriate soil has been in the minds of cricket wicket curators since cricket began in Australia.

The soil used in Australian cricket pitches has a high clay content which swells when wet and shrinks when dry. These cracking clays tend to belong to the vertisol group and have a minimum content of 30 per cent clay fraction and high shrink-swell behaviour. The most common clay minerals in Australian vertisols are illite, kaolin and montmorillonite with the latter type being dominant in the basaltic black earths of eastern Australia. As a group, clays such as montmorillonite, possess the highest cation exchange capacity and undergo the greatest volumetric change during wetting (swelling) and drying (shrinkage) cycles. These characteristics allow wickets to be remoulded at a high moisture content and to crack when dry. The drying is very important for turf recovery as the cracking allows oxygen down to the roots.

 

Cracking helps in rejuvenating the soil/promoting grass growth.

Cracking helps in rejuvenating the soil/promoting grass growth.

Examples of wicket clay soils shrinkage and cracking. 

Examples of wicket clay soils shrinkage and cracking - Photos are courtesy from the Australian Sports Turf Management Journal.

 

The ideal soil will have the following characteristics:

  • Plasticity which allows moulding and compaction;
  • Hardness as the soil dries to provide good bounce, pace and wear;
  • Good binding and stability so the soil doesn’t break up, crumble or turn to dust prematurely;
  • The ability to shrink and crack which allows the soil to recover from compaction and to allow regeneration of structure;
  • Support turf growth.

Should cricket wicket soils be tested? 

All soils designated for turf applications should be tested before being used. Cricket wicket soils are no different and being a specialist application, testing is critical so that the most appropriate soil is installed in the wicket block. There are a range of physical and chemical tests used to characterise cricket wicket soils that have been developed over the past 40 years. Many of the physical tests have been adapted from well-established tests used in soil mechanics for testing clays for use in foundations and load bearing structures.

The following tests detailed in table 1 are the minimum requirements for selecting cricket wicket soils:

Table 1: Typical properties for Australian Cricket Wicket Soils 

 Characteristic

 Preferred range

 Comment

 

 Clay (<0.002mm) - %

 

 50 -70

 

 High clay content required to provide plasticity, swelling, compaction and shrinkage.

 

 Coarse sand (0.2 - 2.0mm) - %

 

 <10

 

 Excess large particles can cause excessive abrasion of the cricket ball.

 

 Organic matter - %

 

 <5%

 

 Excess organic matter affects the characteristics of the clay and can cause the soil to crumble and dust when it dries.

 

 Linear shrinkage ratio

 

 0.08 - 0.15

 

 Measure of how much the clay shrinks when it dries.

 

 Cracking pattern (moist) - no. of fragments

 

 2 -10

 

 Measure of how the clay cracks on drying and restores soil structure after compaction.

 

 Crushing strength

 

 0.8 - 1.6 MPa

 

 Measure of binding strength and ability to resist ball impact without breaking up.

 

 Electrical conductivity (1:5 water) - dS/m

 

 <0.34

 

 Excess salinity affects turf growth and soil structure. 

 

 pH (1:5 water)

 

 5 - 7

 

 May affect the swelling capacity of clay minerals.

 

 Exchangeable sodium % (ESP)

 

 <5

 

 Sodium affects the soil structure and can reduce cracking.

 

Where do I get my cricket wicket soils tested? 

The following laboratories are used by SPORTENG to undertake the testing of cricket wicket soils;

Cricket wicket soils are unique soils used in the turf industry. The swelling and cracking characteristics is the key to providing a hard, bouncy surface and then the recovery from compaction. It should not be forgotten that the turf cover also provides a critical role in the performance of a cricket pitch and will be the subject of a future article.
Remember: With any cricket wicket construction and the development of new sources of cricket wicket soils, testing is essential.

 

Another essential infrastructure linked to cricket are the cricket enclosures. They're some type of batting practice area where club players can get the necessary training without having to utilise the centre wicket/s. They come in various types and have different design and construction needs.  

 

Further reading

Beehag, G. (2019). Wicket Soils Put to the Test. Australian Turfgrass Management Volume 21.3 pp 14 – 20.
Beehag, G. (2020). Black Gold. Australian Turfgrass Management Volume 21.4 pp 66 – 68.
McIntyre, D. S. 1985. Problems of the Melbourne Test Cricket Pitch and their relevance to Australian Turf Pitches. Journal of the Sports Turf Research Institute. June. 61: p. 80-91.
McIntyre, D. S. 1983. Australian cricket pitch soils and profiles. Proceedings: National Seminar on Turf Management.

 

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