Cricket Pitch Performance
Methods for Measuring Pitch Performance - Soils tested are generally for New Zealand and as such, information contained will vary when used for soils of different clay type and structure The Bounce Test Player assessment of cricket pitch pace is subjective and can be variable. Stewart and Adams, carried out a comprehensive cricket pitch research study aimed at the devising objective methods for assessing pitch pace. They set out to determine those features of the soil and its management which influence pitch pace. To assess potential pace of the pitch, they developed the bounce test. Rebound bounce height of the cricket ball dropped vertically on to the pitch from 4.9 meters was measured. They concluded that bounce from a vertical drop was little affected by the thin crust cover with the on a prepared Pitch all by the minute changes in surface roughness from variations in soil texture. The range of individual values recorded was used to provide evidence of: a) Uniformity of bounce Stewart and Adams (1969), used a scale to relate bounce and pace. Dury (1978), found the bounce test to be highly satisfactory for grass cricket pitches, and its use on main number of pitches enabled him to include that the stronger the soil, the higher the bounce and the faster the pitch. Dury observed that lower grade pitches in England exhibiting bounce tests greater than 45 cm were characterized by use of a heavy roller and clay soil. Dury (1978), reviewed developments made with the bounce test. The original 4.9 m drop quite was difficult to work from a prone to eccentric ball delivery. A more convenient ball drop height of 3.0 metres was adopted and rebound bounce expressed in percentage terms as follows: Rebound Bounce (%) = Rebound Height x 100 % Stewart and Adams scale was converted to percentage terms. (Table 1.1) Table 1.1 Relationship of rebound bounce to pitch pace. ______________________________________________________________ Bounce
Pitch Pace _____________________________________________________________ ______________________________________________________________ Percentage
Pitch Pace Over 15.6 %
Very fast Murphy, 1984, discussed the results of a pitch playability survey undertaken throughout New Zealand during the 1983 /1984 season. Playability of pitches was assessed subjectively by players and umpires and objectively by the bounce test. Murphy found that the bounce test results could be related to four categories of pitch pace (Table 1.3). Most pitches studied were in the slow to easy paced category. In general, the pitches unsuitable for cricket fell within the Slow and Very Slow categories. Acceptable pitches also showed a low variation with the bounce test (Murphy 1984). Murphy 1985, found that there was a very close relationship between bounce test variation and subjective assessment of bounce consistency. The Terry Keeling (T.K.) Pitch Tester Dury (1982), introduced a development to assess pitch playability. The T.K. Pitch Tester was developed to simulate the bounce of the ball on a pitch during play. A ball was projected from the tester onto a predetermined area of the pitch and both the point of impact with the pitch and the bounce height was recorded. The design and positioning of the tester produced a similar trajectory of ball delivery to the average medium paced bowler (Dury, 1978). Although it was stated that useful information has been generated using the T.K. Pitch Tester, no results were published. The Friction Test Murphy 1986, stated that while a major proportion of the research undertaken in England has been concerned with the bounce test, pitch pace is not determined by bounce alone. Movement in the horizontal plane, representing pace at which the ball comes onto the bat, and in the lateral plane, representing sideways movement off the pitch, are also important. To measure the influence of these factors, a friction test was developed by Murphy. The test involved the measuring the force required to move a sledge and series of weights on the surface of the pitch. Murphy proposed that the higher the friction the more sideways movement, and also the slower the forward pace of the ball. The bounce and friction tests were incorporated by Murphy into an overall pace rating scale: Pace Rating = Ball bounce During the 1984/85 and 1985/86 seasons, pitches in New Zealand were assessed by this obbjective playability method. A pace rating scale was developed (Table 1.4). Murphy 1986, found that a good relationship existed between pace rating and the subjective assessment of pitch pace. In general, the bounce test on the third day of a match was higher than on the first day, the Pitch was generally slower on the third day. This was due to the pitch surface being rougher on the third day as a result of surface crumbling and wear, thereby coursing the pitch to have greater friction or resistance to the ball. The greater the surface friction the greater the potential for the pitch to take spin, (Murphy 1985). As a result of this study, Murphy outlined recommendations for standards of playing characteristics for one-day, three-day and five-day pitches (Table 1.5). Table 1.3 Relationship of Ball rebound bounce to
pitch pace for New Zealand Pitches. Table 1.4 Pitch Pace Rating Scale
Stewart and Adams (1968), addressed the importance of soil
binding strength. To establish precise significance of soil texture on soil strength of a
developed the Adams Stewart Soil Binding Test. The test involved wetting, molding and
drying spheres of soil (motties) approximately 20 mm in diameter and measuring the force
required to shatter them when compressed. In developing this strength test they attempted
to parallel the sequence of events a Groundsman should follow when preparing a cricket
pitch (Stewart, 1985). From this work, Stewart and Adams developed the following set of
standards: 1. Soils which disintegrate a pressure of up to 45 kg are not
suitable for use on a cricket pitch When developing this test, Stewart and Adams found that the strength value derived for individual soils was significantly influenced by the operator. In effect, the person undertaking the A.S.S.B. Test significantly influenced the soil strength value recorded. Stewart and Adams noted that binding strength values based on the A.S.S.B. test than correlated well with bounce heights measured on county pitches, despite variations caused by weather conditions and wear. It was proposed that this technique could provide a method for predicting the effect on pace of soil materials proposed for use in topdressing pitches. (Stewart and Adams, 1968). The relationship between A.S.S.B. rating and bounce is as follows: Bounce Height (inches) = 0.1 x A.S.S.B. rating divided by 9.0 N.B. MCIntyre (1984), noted that the A.S.S.B. test was developed on non swelling soils, which a light clay or clay loams, (30% - 40% clay). He suggested that the A.S.S.B. test is invalid fro swelling soils because it is too insensitive to the rate and manner of the motty drying. McIntyre postulated that incipient micro-cracks would almost certainly develop in swelling type soils which shrink on drying. The prescence of such cracks would effect the measured compression strength. |