Dr Hewitt explains the need for such a system:
"This [soil] variation is a source of endless fascination to the scientist, but it can be confusing to someone seeking to gain a broad understanding of New Zealand soils in relation to landscapes and land uses. This is where soil classification can provide a sense of the underlying order and pattern needed to assist understanding of New Zealand’s soils and their landscapes."
The relative degree of soil development (horizonation and soil structure) and the degree of alteration of the original rock material or sediments are key factors. Soil colour can provide clues about soil processes and properties: the darkness of topsoil relates to its organic carbon content, grey subsoil can indicate waterlogging, pale-coloured subsoils reflect weak weathering whereas bright red colours indicate prolongued weathering, and white horizons can be the result of intense leaching.
Soil classification generates new knowledge and provides a platform for further research.
![Stylised drawings of the soil groups of the New Zealand Soil Classification (NZSC) used today. Click to enlarge [opens in a new window]](/assets/About-Us/te-rauhitanga/soil-profiles.jpg "Stylised drawings of the soil groups of the New Zealand Soil Classification (NZSC) used today. Click to enlarge [opens in a new window]")
Stylised drawings of the soil groups of the New Zealand Soil Classification (NZSC) used today. Click to enlarge [opens in a new window].
