Module 6:

Turf science

6.4 Pitch construction, drainage & carrying capacity

6.4.3 Rethinking carrying capacity likelihoods

Another way of thinking about carrying capacity is to consider the concept of likelihoods of total games being played for a particular soil type or construction, in relation to the desired quality grade. This latter factor determines the acceptable extent of pitch degradation over the playing season and may, in some cases, be a more helpful way of thinking about carrying capacity.

Example: Football pitch, undrained on sandy soil, with generic comments regarding potential impact on carrying capacity, although these values are only indicative. The desired pitch quality is a medium Grade 2.

Carry capacity comment ¹	Usage ²
A high level of certainty that it should be achieved. If it wasn't achieved, then there would be some significant factors that are negatively impacting on pitch playability and these would need to be investigated.	≤15
A realistic expectation of being achieved	16 to ≤30
A realistic expectation of being achieved during the first half of a playing season. However, for play taking place after the New Year and where a pitch is located in a high rainfall area then higher wear will be expected, potentially leading to a faster reduction in pitch quality and playing experience than in drier regions.	31 to ≤45
A likely possibility in areas with lower rainfall and longer growing seasons. However, this could be an issue in wet regions and the desired number of games may not be achievable.	46 to ≤55
A less likely possibility except where rainfall is less than usual. For consistently wet regions this will be very unlikely. If prolonged dry spells occur over the winter then this could be achievable, but it is not something that could be relied upon.	56 to ≤65
A very unlikely probability and is not something that would be used for planning purposes.	66 to ≤75
A highly unrealistic expectation. Making suggestions with an unrealistically high figure will most likely lead to significant disappointment with everyone concerned.	>75

Notes:

1. Actual compliance with a pitch quality grade can vary depending on parameters used for the individual performance standards, the overall quality rating system used (especially weighting factors for the included performance standards) and the extent of the assessment process. For example, some pitches may exceed the ‘highly unrealistic expectation’ usage figure given primarily due to the rating system.

2. Usage (games) forecast: These figures will also vary (either going up or down) according to the extent and quality of resources used to maintain a pitch. The range of figures start to illustrate the variance that occurs in practice on pitches of the same quality. The values are just indicative values to illustrate the concept of this approach to carrying capacity forecasts and should not be taken to be industry accepted values.

Knowing the desired quality standard, along with the interconnected planned usage, helps a grounds manager to focus attention on relevant maintenance activities that are needed to provide a cost-effectively maintained football pitch.

Yes, you can always spend a lot more money on additional, or more expensive, materials, and physical inputs but there is a rapidly diminishing rate of return for this additional investment. This is because the pitch foundation or construction will have a limited carrying capacity range of values.

Questioning the value of the additional costs and inputs is an important role of the professional groundskeeper, especially when managers, players, or owners are relying on the expertise of the groundskeeper to make well-informed decisions regards pitch management.

For now though, congratulations on completing this Module 6. We will now have a summary of the module before attempting the recall section.

Module progress: 93%

6 | 6.1 | 6.2 | 6.3 | 6.4 | 6.5