Topsoil Standard
"A soil which meets the requirements of the specification would possess the necessary attributes to sustain healthy plant growth in a variety of landscape situations under satisfactory conditions of management."
- R.M.Voelcker (Extract from "A Guide to Specifying Topsoil" Parts 1 and 2 - Landscape Design, March and April 1989).
Major Nutrients
|
pH |
5.5 -7.8 |
|
Electrical Conductivity 1:2.5 (w/v) extract |
<1500 us/cm |
|
Organic Matter |
> 4.0% (w/w) (1) |
|
Nitrogen (N) |
> 0.2% (w/w) (2) |
|
Extractable Phosphorus (P) |
> 45 mg/kg (3) |
|
Extractable Potassium (K) |
> 240 mg/kg (3) |
|
Extractable Magnesium (Mg) |
> 80 mg/kg (3) |
(1) BS 1377, (2) Kjeldahl, (3) MAFF Handbook RB427
Stones
|
Maximum size in any direction |
50mm |
|
Maximum content (2mm-50mm) |
35% by dry weight of which the fraction 2mm-5mm must not exceed 20% by dry weight |
Soil Texture
|
Sand (0.05-2.00mm) |
Maximum 75% |
Minimum 20% |
|
Silt (0.002-0.05mm) |
Maximum 60% |
Minimum 5% |
|
Clay (less than 0.002mm) |
Maximum 30% |
Minimum 5% |