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In Bangalore, a contractor for marriages was called up to erect a tent that would protect the pitch. ©Cricbuzz

Ten years ago, there was a crisis of sorts for Tom Parker, the curator at the Sydney Cricket Ground. The reason for his anguish was dirt, or the lack of it, to be more precise. You read that right. Parker was in distress because the dirt that is used for the pitch at the SCG was running out. It was the same soil that had been used at SCG for over a hundred years. And now, there was a distinct chance that the pitch would never be the same again. The type of soil used was volcanic in nature and was instrumental in SCG having a unique place in Australian cricket. Distinctly remembered to aid the spinners a lot more than any in that part of the world, the Bulli soil was renowned for its high clay content.

Luckily for Parker, they managed to find some, enough to last them another hundred years. The crisis had been averted.

The incident gives an inkling into how the type of soil used is important for a curator and how vital it is to get the right type to create a pitch that is distinct. Over the years, cricket fans have been accustomed to rate the type of the pitch based on just the ground's name - Brisbane is bouncy, WACA is fast, in Headingley there is grass, in the sub-continent it is dry. And we know exactly what type of bowler will be useful on each of these surfaces. We know that grass aids the fast bowlers and the drier pitches aid the spinners. But if we scratch the surface a little more, there can be a better understanding of why pitches behave the way they do. Why does grass aid fast bowlers more than spin? What other factors influence the nature of a pitch?

The answers for that lie with the curators - a unique bunch that sometimes prides itself in being part artists and part scientists. The reason for the former is that they are dealing with highly influential external factors such as the weather, and there are ways in which they overcome the extreme conditions with some out-of-the-box thinking. And almost all of them are required to study the nature of the soil and the amount of clay content that is needed for a particular surface, factors that are also dictated by the weather conditions.

They go on to study the minerals in different types of clay. They study the nature of the grass to be used, the compactness of the soil and further scientific research also tells them the right time to roll a pitch based on the optimum moisture content in it. It is also the combination of these factors that make them an extremely proud bunch.

With pitches being an object of fascination for every cricket aficionado, naturally there is a lot of dissection of its characteristics before every game. Invariably, it also goes on to dictate the combination of every team. Curators are the most sought after people by team members before matches. But they too have a set of guidelines, that they are supposed to adhere to, while preparing surfaces that provide a level-playing field for both teams.

But let's dig a little deeper. All pitches in India are mandated to have three layers. The top eight inches will be the soil of the pitch. This is where the clay content comes into play. The second layer, which is four inches deep, contains loamy soil. This is for fertility and determines the grass growth.

The third layer contains more chunky soil and according to the manual of the groundsman in Dharamsala, also contains a tilt which acts as a drain for water.

There are arguments against such a method which mandates three layers. There been various proposals put forward to ensure that a more scientific approach is followed to the construction of the pitch. A lot of steps have also been taken in this direction, mainly pertaining to testing the type of clayey soil and the minerals (Kaolinite, Illite, Vermiculite, Smectite) present in them.

The minerals in turn, determine if the surface is conducive for grass growth as well as its water-retention capacity. In addition, tests also determine if the clay used is of the type that breaks easily or is prone to crack quicker when drying. Cracking is a direct result of drying clay. So the clay is tested for its water-retention capacity and the ideal ones are those that dry out over the course of five days and not quicker.

The Bulli soil used in South Africa and Australia has properties that aid in keeping the surface hard and bouncy.

On the other hand, there is also the use of red soil at the top in sub-continental grounds. Red soil tends to dry up quicker than other clayey soil, leading to cracks that open up big and the reason as to why we often see spurts of dust after a ball pitches.

For a curator to prepare a pitch according to the guidelines mentioned earlier, a big role is played by how he maintains it, how often is the pitch watered, at what intervals is the roller being used, and what the weight of the roller is. These are in turn dictated again by the type of clay used and its characteristics. External factors such as a sudden change in weather sometimes leave the curator red-faced, but there too, many have solutions based on improvisations to keep the pitch as close to its true characteristic as possible. The days leading up to a match are usually spent trying to produce the kind of pitch that can be got according to the variants at that point of time. As years pass by, such maintenance is also mandatory to make sure the pitch stays true to its color. Any mistake, intentional or unintentional, in the procedures needed for the pitch will end up causing it to play way differently than it had before.

All of these add up in giving us the variety of pitches that we see across the world, each bringing with it, its own set of challenges for the players. A number of them thrive on the craftsmanship of the curator while the very best transcend the work done on it to create their own legacy. Curators have often faced the ire of teams when pitches aren't produced to their liking. There is never a pitch perfect for everyone, but the endeavour to better it is still an ongoing process.

The green covering at Lord's in 2014 when India went visiting caused a lot of flutters ©Reuters

Each format of the game is governed by its own demands. The ICC guidelines vary for each format. For a Test match, the guidelines say that on Day 1, the pitch should be moist with a covering of grass. This naturally aids the seam bowlers and how it does is explained a little later here. On the second and the third day, the pitch should naturally dry off but shouldn't break open so as to allow consistent pace and bounce. This goes on to aid the batsmen. On Day 4, the guidelines state that the pitch should start breaking up. It becomes slower and gradually aids turn. The idea behind such guidelines is that all facets of the game (batting, bowling - both spin and pace) come into play in every game. Of course these guidelines have been challenged routinely in the past and more prominently in recent times but that's a discussion for another day.

What these guidelines also imply include the questions asked previously in this article. So how exactly can these curators mastermind the nature of a pitch and what aids them in this aspect?

The answer - clay and grass. These are the two chief dictators of how a surface will play.

Considering the guidelines, the curators employ various techniques to get the correct nature. The first step is to select the type of clay that has the right minerals, which in turn ensure characteristics such as the compactness of the soil.

In all this, grass plays a big role. Grass in many ways acts as the scaffolding beneath the soil, holding the structure together. But that isn't its only purpose. Grass also acts as a natural drainage system through transpiration. So the amount of watering a pitch undergoes is dependent on the type of grass in the pitch and its water-absorbing capabilities.

While acting as the backbone for curators, grass is also the lifeline of many-a-fast-bowler, mainly because of its dual role.

Like explained before, grass acts as a binding force to the soil. The presence of a green track also means that the soil beneath is held together strongly. So this also indicates that the surface is hard and even. This aids true bounce. What it also helps with is reducing the percentage of pace lost when the ball hits the surface. The Laws of Friction dictate that any delivery loses pace once it hits the pitch. The percentage of pace lost can be kept to a minimum when green grass acts as a lubricant.

When a new ball hits the pitch, the seam is able to dig deeper into the surface than the shiny sides. When the grass blades are kissed by the shiny side, it allows it to go through with minimum loss of pace while the tilt of the seam dictates the direction in which the ball travels after pitching.

On a drier surface, all these aiding factors disappear, rendering many pacers toothless. The best among them resort to fast cutters with the older ball to attain success, but that works just the way it works for a spinner.

A spinner normally doesn't use only the seam position for his deliveries to turn. He uses more of the ball's surface and a similar logic will help him a lot more on drier surfaces that allows the ball to grip far more because there is far lesser grass, which means more friction. The revs imparted by a spinner allow the ball to grip and change direction.

In between these two categories, could be the damp pitch devoid of grass. While the moisture helps in holding the top surface together and smooth, offering even bounce, it also offers some movement. This is because, while the top soil remains hard, there is a tendency for the soil just below to remain a little shaky. So, when the ball hits the turf, due to the movement below, there is also a change in direction of the ball. It isn't rough enough to take spin nor flat enough to deny movement.

Bounce works on the simple phenomenon of elasticity. We've also seen instances of a ball stopping and coming, usually likened to tennis-ball bounce albeit only partially correct. That usually happens on the last two days of a Test, given that the pitch is prepared according to the guidelines mentioned above.

For the sake of better understanding, imagine throwing a ball on water and on hard ground. The ball will land a plop and lose all its velocity and bounce in water. Obviously it goes through much quicker on a hard surface.

Now consider the example when bowling a ball on loose sand. The ball again loses a lot more velocity on such a surface than a hard ground.

The top layer of the pitch, too, in many ways, moves towards the characteristics of loose sand over the course of play. It's for this same reason that a ball tends to lose speed or stops on certain pitches.

All these of course, can be prepared to the desired effects by curators. That's where the nature of the clay used comes into play. This forms the top-most layer of the pitch, the one that is visible to the naked eye. But we'll first move on to what isn't seen.

Most pitches in India are prepared with the help of knowledge passed down through the years. The groundsmen collate their ideas with those mandated by the ICC to try and create pitches that match the conditions. Not always do they come out with a 100 per cent success rate, but the endeavor is almost always the same.

Of course, there are special conditions where a word from the home team might influence preparations, but in almost all cases, it can't be done unless they have had the word at least 10 to 15 days before a match starts at a particular ground.

The weight of the roller and the time intervals of rolling play a huge factor in the way a pitch plays ©Reuters