Carrying Capacity

There are several variations on this term although the main focus and interpretation within turf management is based on that of Ecological Carrying Capacity. This is the maximum level of use that can be sustained which does not cause an unacceptable reduction in the quality of the surface. For sports pitches, this relates to how much usage can take place without creating a surface that produces an unacceptable standard of playing surface. Carrying capacity can be modified by applying a range of construction methods and management practices.

Sports pitch carrying capacity is a guide for an entire playing season which is averaged for a typical week, being related to adult equivalent usage. For example, if a football pitch can sustain 105 games (for a defined level of quality) over a 35-week period, this averages as 3 games per week. However, ground conditions will vary, so some weeks the pitch may be able to sustain more games whilst others it will be less. It is a frequently misunderstood and misapplied term, often resulting in a reduced quality of playing surface much sooner than if managed correctly. Carrying capacity is also called Sustainable Use.

The age and weight of users impacts on the extent of wear exerted on a surface and general guide of indicative hours of use per week over a winter period, with actual usage heavily influenced by frequency and extent of rainfall, as well as the desired level of quality that is to be consistently achieved, might be as follows:





Age Group (& hours of use per week)
General pitch type <11 11 - 12 13 - 14 15+ (inc. Adults)
Playing field with heavy soils <2 - 8 <2 - 6 <2 - 4 <2
Playing field with sandy soils 8 - 16 6 – 12 4 – 8 2 – 4
Pitches with surface drainage schemes 12 - 24 9 – 18 6 – 12 3 – 6
Constructed sand profile type 16 - 24 12 – 18+ 8 – 12+ 4 – 6+
Constructed profile with reinforcement-hybrid material 24 - 42 18 - 36+ 12 - 30+ 6 – 18+

To assist in the effective and sustainable management of a turfgrass surface it is not just good practice, but actually essential, to identify the likely carrying capacity of a turfgrass surface, especially sports turf surfaces.

By understanding the carrying capacity of a turfgrass surface, turf managers will be able to make informed decisions for optimum maintenance and management requirements. This will help deliver a surface that is sustainable and provide a more consistent playing experience. It will also enable stakeholders, who will have access to better information, to contribute more positively to decisions that affect turfgrass surfaces, allowing them to have a greater affinity to ‘their surface’. Having an understanding of the carrying capacity of a surface, which will primarily be based on the soil / construction, type helps to manage expectations of users and senior managers and is an important precursor to understanding realistic quality levels which can be achieved from the surface on a consistent basis.

Managing the user of a turf surface is an important role within turf management and this should be reflected in the use of policies such as for match cancellations, diverting usage from areas or closing off some areas.

The carrying capacity of a turfgrass surface is a helpful, informed, guide to the level of use that might occur, although because of natural variability, such as extreme or inclement weather conditions and especially the management of the user there will be a variance from any initial estimate. For example, playing a football match in very wet conditions will considerably increase divoting and overall wear on a pitch, resulting in a much reduced carrying capacity. The type (e.g. age group, intensity of use) and pattern of usage (e.g. mostly at weekends, concentrated / staggered / spaced out periods of use) will also affect the actual carrying capacity.

Other variations of carrying capacity include Ecological Carrying Capacity, Economic Carrying Capacity, Perceptual Carrying Capacity and Physical Carrying Capacity.

It might be useful to think of carrying capacity as having two different perspectives:
Effective (or Potential) and Actual.
• Effective carrying capacity will be what could be achieved given optimum use and management strategies being implemented and is more of a forecast as to what could realistically be achieved. Figures quoted for sports pitch carrying capacities are usually the effective carrying capacities.
• Actual carrying capacity is looking back over what has been achieved and may vary from the effective carrying capacity due to how use and management strategies have actually been implemented in practice.