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).
| 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
| 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 |
| 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% |
