1. Consider access for deliveries – tight/poor access affects the size of the delivery wagon which transports the aggregate, which in turn will affect price.
  2. Consider storage, for long term storage all aggregates should be covered to prevent them getting too wet or contaminated. All aggregates should be stored in piles no higher than 2 m on a clean, dry and level base.

 

Topsoil

Topsoil should be sourced from a reputable sports turf supplier and the following information needs to be provided:

  1. The soil should comply to BS3882:2015. The supplier should provide an up to date certificate to prove compliance (in the previous six weeks following delivery).
  2. Textural analysis to include the ratio of sand, silt, and clay. For most sports turf requirements the soils should fulfil the requirements of a sandy loam/loamy sand texture i.e. comprise a minimum of 70% sand.
  3. The pH should be in the range 5.5 – 7.5.
  4. Organic Matter content should be in the range 2 – 8 %.

 

Sand

Top dressing/Amelioration

Sand is normally used to improve drainage characteristics and to dilute high organic matter content of winter games pitches and is often applied as a top dressing or to ameliorate into the soil when constructing new pitches. Sands should be sourced from reputable sports turf suppliers. For winter games pitches the main considerations are:

  1. The correct particle size distribution is essential; sand particle size affects two key parameters essential for pitch performance – drainage and stability. Coarse sands increase drainage rate but decrease stability, fine sands decrease drainage rates but increase stability. Traditionally sands used for winter games pitches are focussed in the medium/fine category and should comply with the following particle size distribution:
    V. coarse sand (2.0 - 1.0 mm)<5%
    Coarse sand (1.0 - 0.5 mm)5 - 15%
    Medium sand (0.5 - 0.25 mm)55 - 70%
    Fine sand (0.25 - 0.15 mm)10 - 30%
    V. fine sand (0.15 - 0.05 mm)<5%
  2. Be non-saline (electrical conductivity < 0.75 dS/m), and contain less than 0.5% (w/w) CaCO3.
  3. Have a pH in the range of 5.5 - 7.0.

Drainage

Sand or rootzone (a blend of sand comprising a high (70-80%) proportion of sand with topsoil) is normally used to form the upper 150mm – 250 mm profile of drain runs and sand slits/sand bands (above a gravel aggregate).

The sand or rootzone has to combine good drainage performance (termed ‘saturated hydraulic conductivity’) and good nutrient and moisture retention (to aid grass germination and growth). Therefore, the same sand is normally used for both drainage and construction/top dressing. Not only does this provide the requisite performance parameters, but also compatibility with the upper profile of the pitch.

This is important as a finer textured layer of sand/soil over a coarser drain /sand band profile can impede water infiltration.

Rootzone

Often rootzone is used instead of sand for drainage, top dressing or construction. This is due to the increased nutrient storage capacity, increased moisture retention and better stability compared with straight sand.

Most commercially available rootzones comprise a blend of 70 – 80% sand with 20 - 30% sandy loam topsoil. Often users request the blend of sand: soil that they require without giving consideration to the type of soil used. Soil type has an enormous effect on the particle size distribution of the final product. For example, a 70:30 blend, using sandy loam topsoil, could contain a lower fines content (very fine sand, silt and clay content) than an 80 :20 using a clay loam topsoil. Therefore, in addition to stipulating the blend, also request a recent data sheet to check that it complies with the required performance. Specifically the user needs to know:

  1. The particle size distribution, which should comply with the following criteria in most situations:

    Particle Size (mm)% Retained
    Very Coarse Sand (2.0 - 1.0mm)<2%
    Coarse Sand (1.0 - 0.5 mm)5 - 15%
    Medium Sand (0.5 - 0.25 mm)55 - 70%
    Fine Sand (0.25 - 0.15mm)15 - 30%
    Very Fine Sand (0.15 - 0.05mm)<5%
    Silt (0.05 - 0.006mm)<3%
    Clay (<0.006mm)<2%
    Total Fines (VF Sand + Silt + Clay)<10%
  2. The saturated hydraulic conductivity (drainage rate) should be greater than 150 mm per hour in most situations.
  3. Organic matter content should be in the range of 0.5 - 2.0%.
  4. pH should be in the range 6.0 - 7.5%.
  5. The mix should be homogeneous i.e. not contain larger lumps of soil.

There may be some situations where increased moisture and nutrient retention are preferred e.g. areas of low rainfall (increasingly an issue in the south east and eastern side of England). However, the user needs to be aware of the potential risks of using higher soil content mixes and should still obtain the data sheet to check that the hydraulic conductivity is at an acceptable level.