Cricket Pitches

There are no published or written guidelines or quantifiable standards for the preparation or construction of a turf pitch. The majority of cricket pitches in the continental and subcontinental regions are typically prepared and set out based on the extensive experience that groundsmen and curators have amassed in the field of pitch making. By interacting with the weather factors present within and above the pitch surface, dominant clay minerals with exchangeable cations and a proportionate amount of clay, silt, and sand are viewed as the genes that control the pitch’s behaviour by regulating its cracking or crumbling patterns, WHC, surface density, compression levels, etc. It is said that a uniform, high-quality pitch is necessary for playing excellent international cricket. A decent cricket field should allow for a competitive match between the bat and the ball. It ought to be suitable for stroke play and have a good pace, consistent bounce, and excellent ball carry. Above all, it should be goal-oriented, and the surface shouldn't ever become hazardous for the batsman or unplayable.

Cricket pitch soil mineralogy, which is fundamental to any soil and a resultant of the weathering of parent material, acts as the DNA of pitch soil and provides a template that defines the morphological, physical, chemical, and biological behaviour of a cricket pitch. The quantity and quality of clay minerals present in the pitch soil determine the behaviour of the pitches as the match progresses. The desirable behaviour of a cricket pitch in any format of match (ODI, T-20, Test matches) is good pace, consistent bounce, good ball carry, and turn. This is only possible if the cricket pitch soil has good structure, plasticity and elasticity, cohesiveness, high swelling and shrinking capacities, and a very high external and internal surface area to have the entrapped capillary, hygroscopic, and film moisture required for desirable compression levels during various phases of the match. The above-mentioned parameters are generally governed by the pitch soil having a high proportion of swelling and shrinking clay rich in smectitic clay minerals. Smectites with large internal and external surface areas, as well as an adsorbed double diffused film of non-available water, serve as a good source of the optimum moisture content required to achieve the desired pitch behaviour during the course of the match (particularly in Test matches). Much more concentration and effort are confined to the physical and chemical analysis of the soils to be used to prepare a pitch profile. Previously, only some physical and chemical analysis of pitch soils was considered a litmus test for the preliminary acceptance or rejection of the pitch soil samples. Soils with high clay contents and acceptable desired physical and chemical parameters were generally accepted for laying down the pitch. However, recent research indicates that the predominant mineral type present in the clay proportion of the soil used in the cricket pitch is far more important than the high percentage of clay content alone. Pitch soils with very high clay contents but with a major portion of non-expanding clay minerals such as illite or kaolinite are undesirable as pitch soils. On the other hand, pitch soils even with low percentage of clay, but having smectite or mixed layer minerals rich in smectite, vermiculite type of clay minerals are most desired as a pitch soil. Though quantitative and qualitative analyses of pitch soil clay mineralogy through X-ray diffraction (XRD), infrared spectroscopy (IS), scanning electron microscopy (SEM), differential thermal analysis (DTA), dye absorption, cation exchange capacity (CEC), etc. are available, these are time-consuming and expensive. Hence, the use of simple techniques to identify the type of predominant clay mineral present in soil that are less time-consuming and easier to perform is sufficient for assessing the behaviour of cricket pitch soil. These simple methods can be grouped as direct methods (free swelling ratio, coefficient of linear extensibility, expansion index, and the like) and indirect methods (Atterberg limits, particle size distribution, clay activity). This chapter is an effort to examine the importance of the clay mineralogy of pitch soil, their different identification methods, and how the mineralogical composition influences the morphological, physical, and chemical composition of cricket pitch soil, thereby controlling the behaviour of the cricket pitch surface.

Based on a critical evaluation, analysis, and interpretation of the physical, chemical, and engineering properties of soils for cricket pitches of all the cricket associations across the country (by the IIT Powai through the BCCI in Mumbai, the ICAR-NBSS and LUP in Nagpur, etc.), it was found that there is a wide variation in the desirable particle size distribution (moderate clay, very high silt, and less fine or medium sand) and in their recommended proportions or in the types of predominant desirable clay minerals. The Indian subcontinent has the richest source of swelling and shrinking smectite-dominant fine clay soils desired to construct cricket pitches. More than 240 million hectares of vertisols (swell-shrink clayey soils high in smectites) are distributed throughout the world (Buol et al. 1997). They are extensively distributed in Australia (80 million ha), India (73 million ha), and Sudan (50 million ha). In India, these types of soils occupy nearly 22% of the total geographical area of the country. Though the most smectites are found in the Indian states of Maharashtra, Andhra Pradesh, Madhya Pradesh, Tamil Nadu, Chhatisgarh, Karnataka, and Gujarat. This wide variation in the desired particle size distribution (PSD), physical, chemical, and mineralogical composition in Indian cricket pitch soils can be reduced by benchmarking the desired cricket pitch soils based on a variety of research-based (mineralogy—XRD, CEC, etc.), direct (FSI, FSR, COLE), and indirect (Atterberg limits, clay activity, etc.) index properties.

Curators construct and prepare the wicket (subcontinental or continental pitches) in almost all the available pH ranges, varying from very strongly acidic (4.5–5.00), neutral (6.6–7.3), to very strongly alkaline or sodic levels (pH levels > 8.5, ESP > 15, EC 4 mmho/cm). Without considering the influence of pH on cricket pitch performance, methods and techniques adopted for pitch construction and maintenance (such as watering, rolling, or turf management concepts) remain more or less the same. However, the behaviour of a cricket pitch in terms of water retention, holding capacity, compressibility, swelling and shrinking, or crumbling patterns varies greatly depending on the pH of the cricket pitch soil. Irrespective of keeping all other factors of pitch construction or match pitch preparation the same, the pitches behave differently depending on the pH of the soils used. However, there are some exceptions where the effect of pH is obliterated by the presence of salt or natural modifiers (gypsum, zeolite, etc.). Curators will find it easier to prepare a wicket with pitch soil under slightly to moderately alkaline conditions (with Ca⁺² or Mg⁺²-dominant smectite fine clay and good soil structure) because the desired pitch variations and objectives are generally achieved through natural pitch wear and tear. A cricket pitch surface with adverse pH (very strongly acidic pH less than 4.5 with Al⁺³ toxicity and flocculated structure) or extremely alkaline or sodic soils (pH > 8.5, ESP > 15, and SAR > 13–15) with dispersed soil structure is extremely difficult to handle and necessitates entirely different pitch construction and pitch preparation methods. Considering the desirable surface stability for various engineering purposes, soils within the normal pH range are preferred. The preferred pH of the soil used to construct any cricket wicket pitch profile is near neutral (6.6–7.3) or slightly alkaline (7.4–7.8) to moderately alkaline (7.9–8.4) to achieve the desired density levels of the pitch surface for generating pace and bounce or after-match recovery of the pitch surface and turf grass. In 2008, seventy-six different soils used in India for preparing cricket pitches, which were under use for conducting various domestic and international cricket matches, were examined by IIT Bombay in collaboration with the BCCI for their chemical properties, namely pH levels, electrical conductivity (EC), total dissolved solids (TDS), chloride, and sulphate levels. However, no analysis or scientific interpretation of this valuable data was performed in order to comprehend the impact of chemical properties on cricket pitch behaviour. This chapter presents an insight into the need for a scientific evaluation and interpretation of data on the chemical analysis of soils used in cricket pitches and whether different soil pH ranges can be considered so as to categorise the cricket pitches. This would suggest developing different methodologies for analysing and interpreting cricket pitch behaviour and preparation methods while taking into account the various soil chemical properties, particularly soil pH.

Pitch soil moisture controls the morphological, physical, chemical, biological, and mineralogical activities of pitch soil complex and is highly dependent on the quantity and quality of pitch soil colloidal complex (both inorganic and organic). The exclusive colloidal behaviour desired for the pitch comes in the form of high swelling and shrinking capacities, good cohesive soil structure, plasticity, elasticity, high water holding capacity (WHC), compression levels, etc. These are totally dependent upon the presence and absence of available (as capillary water in the macropores) or non-available (as capillary water in the micropores or hygroscopic water tightly adsorbed to the clay micelle forming the diffused double layer in vapour form) water in the pitch soil complex. The entire art of pitch curatorship revolves around achieving the best available consistent compression levels (at a predetermined optimum moisture content) in the pitch profile via the different roller weights and rolling schedules, and uniform deep drying of the pitch profile (both in liquid and vapour form) via the pitch grasses. The pitch will behave differently if it is prepared at different levels of entrapped available water within the pitch profile. Furthermore, the swell-shrink behaviour of clay and humus-dominated soil pitches is completely dependent on soil moisture levels in order to provide the pitch profile with the maximum bulk density. The extent of swelling and shrinking is limited to the presence, absence, or movement of water in the pitch profile. Nearly all forms of soil moisture (either gravitational, capillary, hygroscopic, or film moisture) are available in the pitch profile during the match pitch preparation and during the match days. Due to diurnal weather variables such as temperature, relative humidity, evapotranspiration, dew, solar radiation, and so on, their movement and retention within and just above the pitch profile (either in moisture or vapour form) generate the desired pitch surface behaviour. The available water capacity (PAWC), water holding capacity, and retention capacity of pitch soils with smectite, illite, or kaolinite-dominant fine clay differ, resulting in different pitch surface behaviour. The art of regulating the pitch behaviour at the time of the pitch preparation process and during the matches by regulating the moisture level within the pitch profile has a scientific logic and reasons behind it. The following chapter is an attempt to unravel some myths related to the quantitative and qualitative use of water within the pitch profile and to correlate and establish the scientific logic and reasons behind them.

One of the main reasons for a fast and bouncy wicket is uniform, deep-rooted grass growth in turf pitches. This helps deep even drying and desiccation through evapotranspiration (nearly four inches of pitch surface) and by giving the pitch soil a firm structure (with a high combined tensile and shear strength). The turf acts as the skeleton of a pitch profile, which provides a firm shape and structure to it. The deep-rooted grass acts as a skeleton or base and gives the pitch profile a clear, firm shape, and structure. Every morphological part of the turf grass (such as stolons, rhizomes, stems, and leaves) has a very specific role to play in defining and shaping the pitch behaviour during the pitch preparation process, matches, and after-match recovery of the pitch profile. Deeply grown pitch grass roots in turf wickets (with a high tensile strength, root area ratio, root length diameter, and rhizosheaths that act as glue) increase the soil structure, cohesion, adhesion, shear, and tensile strength of the pitch soil matrix. This helps make a pitch with a good structure and a consistent pace and bounce. Turf grass, with its ideal morphological features, regulates the pitch soil temperature and soil matrix moisture level through the process of evapotranspiration, which is the prime requisite to attaining the best level of compression in the pitch soil complex (Singh 2017). A major advantage of the Bermuda or couch grass is its ability to produce rhizomes and stolons, which add tensile strength to a pitch soil matrix, helping to hold the soil aggregates together. The grass turf cover affects the pitch's behaviour by generating pace and seam and minimising the wear and tear of the pitch surface. Though specific research on the significance and effectiveness of cricket pitch turf grasses in India and elsewhere is still in its early stages, this chapter is an effort to understand the importance and role of grass vegetative cover and roots within the cricket pitch profile matrix and how the turf grass affects the pitch's behaviour during pitch preparations and match days. It also deals with the various logical scientific reasons behind the art of turf pitch making (based on recent research and developments), taking advantage of the available research in the concerned field and the skills and vast experiences of the curators and groundsmen gathered over a long period of their professional services.

Cricket pitch soil contains only a trace amount of organic matter (less than 2%), but it has a significant impact on the morphological, structural, physical, chemical, mechanical, and mineralogical composition of the soil, influencing the nature and behaviour of pitches either directly or indirectly. Since it is far less dense than mineral matter, organic matter accounts for only two per cent of the weight of the soil. Humus particles have more nutrients and WHC by weight than clay particles. However, clay is generally present in larger amounts; its total contributions to the physical, chemical, and mineralogical properties of soil will usually equal or even exceed those of humus.

Rollers with different compactive potential and turf pitch grass (for controlled desiccation and drying of the cricket pitch profile through evapotranspiration) under available weather variables (temperature, relative humidity, solar radiation, evapotranspiration, etc.) are the basic and important tools through which the curators achieve the desirable pitch surface target density at a particular moisture content. Considering the format of the match (either the desirable pitch surface density during the Test match, ODI, or T-20 matches), pitch soil structure, morphology, physical, chemical, or predominant mineral type, weather variables, etc., smooth-wheeled manual or mechanical rollers of different weight, and compactive potential are used to achieve the desirable pitch surface density levels. Rollers compact the pitch profile based on their compactive potential and the compactive potential of the pitch surface. However, the presence of dominant clay minerals in the soil (the physio-chemical and mineralogical composition of the soils being used as pitch soil) used for constructing the cricket pitch profile and turf grass has a significant role in controlled and uniform drying and desiccation of the pitch profile and helps in attaining the desirable pitch surface density levels at different phases of the match. A pitch soil having flocculated or deflocculated structures with predominant exchangeable Ca²⁺, Mg²⁺, or Na⁺ (under moderate saline or alkaline conditions) and dominant swelling and shrinking fine clay smectites, or with Al⁺³, H⁺ (under moderately acidic to neutral conditions) and dominant non-swelling fine clays, provides entirely different compression levels and needs entirely different rolling and drying techniques and schedules to achieve the desired pitch surface density levels. On a fine swelling and shrinking clay-dominant pitch surface, the desired turf pitch surface density is not only mechanically achieved by compacting the pitch surface with few passes, but the total achievable target pitch surface density is the combined effect of mechanical compaction (via smooth-wheeled rollers) and pitch surface drying or desiccation under the prevailing macro- and microweather and climatic variables available within and just above the pitch. A finely swelling and shrinking Ca⁺²/Mg⁺²/Na⁺ smectite-dominant pitch surface achieves the desired turf pitch surface density via recurrent rolling with rollers of varying compactive potential and slow drying of the pitch surface due to desiccation shrinkage, resulting in surface cracks of various shapes and sizes. Few passes (6 to 8) with light to medium weight rollers are usually sufficient to achieve desired compression levels on non-swelling fine kaolinite dominant clays (with low water holding capacity and high hydraulic conductivity) or loamy clay soils. Very limited research is available in the cricket arena to define and justify the total compression levels achieved through compaction or dessicative drying of the turf pitches (having different textures, morphologies, structures, physical, chemical, or mineralogical compositions) under variable climatic and weather variables. Apart from the compaction levels achieved through the different rolling schedules and techniques, the compression of the pitch profile through the drying and desiccation of the pitch surface under the prevailing weather and climatic variables, which induces variations on the pitch surface (by developing cracks of different shapes and sizes or crumbling of the pitch surface) during the course of the game, needs to be verified and quantified. It’s an effort to understand the “science behind the art of cricket pitch soil compression” and how the desirable pitch behaviour can be regulated through various pitch-making rolling and drying techniques and schedules. The purpose is to understand the different phenomena involved in attaining the variable or desirable compression levels in different formats of cricket matches (either Test match, ODI, or T-20) and how these different compression levels can be attained and retained by controlling pitch soil structure, pitch soil (clay quantity and quality), adsorbed and exchangeable cations, turf grass growth and density, pitch compactive potential, roller compactive potential, rolling schedules and techniques, etc.

The goal of this chapter is to understand the fundamental scientific principles and logic underlying the art of measuring, analysing, and interpreting pitch surface behaviour (based on their morphological, structural, physical, chemical, and mineralogical properties, predominant exchangeable cations, existing weather variables such as temperature, relative humidity, evapotranspiration, solar radiation, wind speed, match format, cracking and crumbling patterns, and so on) and as to how to develop, analyse, and interpret the pitch behaviour through the Pitch Behaviour Analysis Index (PBAI) and Pitch Behaviour Forecasting (PBF) based on the Pitch Quality Index (PQI) and Database Management System (DBMS) of a cricket pitch profile. The following analysis and interpretations on the pitch behaviour (national and international) aspects are part of the pitch interview with Shri Mahendra Singh Dhoni; they include many senior players representing the national and international matches; senior coaches and managers representing the BCCCI and JSCA; the response and feedback of some seasoned Indian curators (representing the BCCI and various states) on the pitch questionnaire; group discussions and interactions done at the various seminars and training programmes organised by the Pitches and Grounds Committee of the Board of Control for Cricket in India (BCCI); Jharkhand State Cricket Association (JSCA); Clay Mineral Society of India (CMSI); IIT Mumbai, etc. Every cricket pitch, based on its morphological, structural, physical, chemical, mineralogical, predominant exchangeable cations, and existing weather variables such as temperature, relative humidity, evapotranspiration, solar radiation, wind speed, generates its own specific environment and expresses its behaviour either through cracking or crumbling of the pitch surface (through loss of pitch surface density and moisture levels). After a few (3–4) wetting and drying cycles (during pitch preparation), a pitch surface dominated by swelling and shrinking fine clays maintains equilibrium and follows the same cracking patterns (initiation, propagation, geometry, shape, size, depth, etc.) afterwards. By measuring and mapping the cracking and crumbling patterns in equilibrium after the initial 3–4 drying and wetting cycles, the individual pitch behaviour during the different phases of multi-day matches can be mapped, analysed, and narrowly predicted. Cracking or crumbling patterns can be used to forecast pitch behaviour based on the PBAI, PQI, and DBMS, just as weather forecasting or financial forecasting of any stock market is done. As 30 stocks from the Bombay Stock Exchange (BSE) and 50 stocks from the National Stock Exchange (NSE) are used as index values to analyse and interpret the entire stock market's behaviour, the same index-based criteria of an individual cricket pitch surface (based on their morphological, structural, physical, chemical, mineralogical, predominant exchangeable cations, existing weather variables such as temperature, relative humidity, evapotranspiration, solar radiation, wind speed, their cracking of crumbling patterns) can be considered scientifically to evaluate, analyse, interpret, comprehend, and predict the pitch behaviour. Based on after-match statistical results, pitch behaviour can also be analysed and interpreted through the match pitch index.