Two authors, two purposes
The confusion is understandable, because both specs exist for the same underlying reason: "topsoil" with no spec behind it means whatever is in the stockpile. Both put laboratory testing between the stockpile and your site. The difference is who wrote them and what they were written for.
| AS 4419 | VR720 (Section 720) | |
|---|---|---|
| Written by | Standards Australia | VicRoads |
| Full name | Soils for landscaping and garden use | VicRoads Standard Specification Section 720: Topsoil |
| Built for | Landscaping and garden construction: planting beds, garden works, designed landscapes | Road projects: batters, medians, verge reinstatement, roadside revegetation |
| Typically specified by | Schools (VSBA), councils, landscape architects, commercial landscape packages | Road and rail corridor works, civil contractors on VicRoads-referenced jobs |
| Tested for | pH, salinity (EC), organic matter, nutrients and toxicity | Grading, pH, organic content and weed contamination per Section 720 |
Why you cannot swap one for the other
Both are tested topsoils, but they are tested against different requirements by different authorities. A batch with paperwork against AS 4419 has not demonstrated conformance with Section 720, and vice versa. The superintendent signs off against the spec named in the contract, so supplying the other one, however good the soil, leaves the paperwork unable to close.
If a substitution genuinely makes sense on your job, that is a conversation with the superintendent before the trucks roll, and it belongs in writing.
Ordering it right
Name the spec when you order, give the volume in cubic metres, and ask for the current batch test documentation with delivery. That is the entire trick. The paperwork arriving with the soil is what keeps sign-off moving, and it is why specified soil is ordered from suppliers who test, not from whoever has a stockpile.
For the broader picture of what AS 4419 covers, read What is AS4419 soil? For how VicRoads specifications work in general, see VicRoads specs explained.