Fast and bouncy cricket pitches

An interesting and informative paper was presented at the Annual Sessions of the Institution of Engineers of Sri Lanka recently by Dr U.P.Nawagamuwa,(Dr U.P.N) a Senior Lecturer in the Department of Civil Engineering of the University of Moratuwa, titled “Improvement of local soils in order to make fast and bouncy cricket pitches.” I reproduce hereunder a few relevant extracts of his paper.

“Data was gathered from local pitches by collecting and analyzing soil samples from Test venues in the vicinity of Colombo. This data was then compared with data from other countries, especially Australia. It was found that local pitches had a high silt content, low clay content and low plasticity due to a difference in clay mineralogy when compared to Australian pitches.

It was hypothesized that by reducing the silt content and improving the plasticity by the introduction of Bentonite(a clay type with very high plasticity) into the soil, will produce a faster and bouncier pitch of similar character to those in Australia. Small scale model pitches were built and then tested to find the effect of additional Bentonite on the pitch characteristics.” Dr Nawagamuwa has classified the soil grading of Australia and Sri Lanka Cricket pitches as follows:

Australia - Average Clay content - 63%, Average Silt - 14%. Average Sand - 18%.

Sri Lanka - Average Clay content - 30% , Average Silt - 60% Average sand - 7%.

The clay content in Australian pitches vary from 82% in Perth to 51% in Adilaide.

The clay content in Sri Lanka vary from 45% to 20%. The silt content in Australia vary from 5 to 20%. In Sri lanka the silt content varies from 45 to 80%.

Dr. U.P.N. has acknowledged the views of experts that Sri Lanka pitches differ from pitches in Australia and England in three characteristics namely, pace, bounce and deterioration.

“The methodology adopted was to compare the soil make up of Sri Lankan pitches to those of Australian pitches, identify the major differences, modify the local soil so that these differences were minimised, and conduct tests to check how sucessful the modified soil was, at producing faster and bouncier pitches.” Dr. U.P.N. has opined that the weakness in the Sri Lankan soils as compared to Australian soils is that:

1. Clay content is too low. 2. Silt content is too high. 3. Plasticity of the clay present is low.

For his Tests, he has modified the soil as follows: Clay from 25% to 45 %. Silt from 65% to 45%.

The models had been tested in the laboratary after compaction of the soil to the required degree. The following tests had been carried out: 1.Bounce test. 2. Friction test. 3. Penetration test. 4. Crack pattern observation and crack width measurement. 5. Moisture content measurement.

Dr. Nawagamuwa has stated that further testing will be done to supplement what has been found through this study.

Dr. Nawagamuwa and his team has taken great pains to carry out this investigation, which is a god send as far as Sri Lanka Cricket is concerned. Sri Lanka Cricket should give him all the assistance required to carry his study to its logical conclusion so that ultimately the Selectors and the Captains will be in a better position to select their teams and also decide at the toss, whether to bat or bowl first. This study is only a start, but a fuller study should be made of the different venues.

The author and his team has not made a detailed study of the type of grass used, the amount of grass on the pitch and their implications,the effect of watering and rolling using rollers of different weights etc. These tests should be done under actual playing conditions in the field and not in the laboratory.

But this is a tremendous start, and what a big boost it will be for Sri Lanka if we could advise the I.C.C, the parameters within which all Cricket pitches for International matches should be prepared, so that the reading of pitches will not be a guessing game any more. I have spoken to Dr Nawagamuwa and he is quite willing to continue his study with the help of Sri Lanka Cricket and he has suggested a Committee to be formed to pursue this exercise further.

I would suggest that A. Polonovita and Ranil Abeynaike both of whom have a very good knowledge of the preparation of pitches, to be included in this committee. Finally, as a person who had been associated with Sri Lanka Cricket for over 2 decades, and currently a well-wisher of Sri Lanka Cricket,I wish to thank Dr Nawagamuwa and his team for all the trouble they have taken so far to add a new dimension to Sri Lanka Cricket.

Neil Perera (former Hony. Secretary Board of Control for Cricket and former manager Sri Lanka Cricket team)