Football Pitch Performance Standards (B) 
4) Undesirable grasses: Annual meadow grass is the primary undesirable grass. Whilst this species can readily colonise thin and bare areas, it offers poor traction and is easily kicked out of a sward. Monitoring encroachment of this grass should be fairly easy, once correct identification has been mastered, and this can help to adjust maintenance inputs to improve the competitiveness of the desirable grasses at the expense of this grass. The maximum content of this species might be from 5% to 40% depending on standard required.
5) Sward height: Keeping the grass cut height at a suitable level is essential, whilst also ensuring that the grass does not grow too long before it is cut is also an essential requirement. Aiming to follow the 1/3rd rule of not removing too much leaf growth per cut is important if a resilient and long-lasting surface is to be produced. The length of grass will also significantly influence the speed and rolling distance of a ball and often the height of cut can be kept relatively high to match the abilities of players, without the need to have too short a sward which can produce too fast a pace game for many players.
This is often given as playing season and out of playing season but might be better categorised as: match preparation – day of match; in-between matches; renovation period, all other times outside of the playing season. The majority of parameters will be between 25mm and 50mm, with higher quality pitches having narrower parameter and maybe also a slightly lower figure for match day.
Allowing a pitch to recover from wear experienced during a game will typically require a slightly higher height of cut being adopted. For a good quality pitch this might mean a match-day prepared pitch height of cut as being between 25mm and 38mm, whilst in-between games the height might be between 35mm and 60mm. Interpreting this for a specific pitch might see match day height of 28mm and in-between height of cut being 38mm.
6) Root depth, and root density: Ideally grass roots will be as deep as the soil profile allows. A root depth (which should be measured where most of the mass is, not where just a single rootlet extends to) of 50mm would be considered an absolute minimum which needs improving on, whilst a depth of 150mm would be considered excellent in practice. Root depth and density are good indicators of the effectiveness of the mowing, aeration and irrigation practices in particular.
A shallow depth of roots will reduce sward resilience, have more divots easily kicked out, more readily reduce the quality of the sward and will also have less drought resistance. Significant quantities of roots are typically within the top 50mm of a profile, however, to encourage good maintenance practices values can be given for the percentage mass of roots at different depths. This might be a maximum of 40% within the top 50mm and a minimum of 60% at depths greater than 50mm, with at least 20% also being greater than 100mm.
7) Weed content: This can be a general indicator of everything or one that has sub-categories of large-leaved weeds, small-leaved weeds, moss and algae. A small amount of weed infestation shouldn’t be a particular issue for most pitches. However, deciding on the parameters where action needs to be taken will relate to the extent of ‘pristineness’ wanted from a pitch. High weed contents, especially where they are concentrated in clusters will reduce surface traction and increase the slipperiness of a surface, increasing the potential for injuries such as strains. For some highly maintained pitches a weed content of no more than 0.5% might be desired, whilst for a general pitch a content of 30% might be acceptable.
8) Earthworm surface casting: The total ground cover area that has earthworm casts present. So, this can be coverage on the live vegetation, dead vegetation or bare area. Surface casts can reduce the effectiveness of sand-slits where the casts have begun to seal the surface of the slits and where they have contaminated the sand within the slit, reducing the water infiltration rate. Using machinery in damp or wet conditions will also squash and smear casts further contributing to reduced infiltration rates. A small number of casts isn’t going to be a problem, but as the density of cast increase so will the problems and challenges in overcoming the negative effects of these. On general quality pitches a coverage of 10-15% might start to create issues with maintenance work, although increasing sandy top-dressings can help to dilute and reduce the effects of surface casts. The beneficial effects of earthworms within a soil, especially regards improved soil aeration and breakdown of organic matter should not be overlooked.
Instead of measuring the percentage coverage from earthworm casting another method is that of counting the number of earthworm casts per m2, which might be just as satisfactory an approach.