5.16 New Zealand Soil Classification

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System Title	5.16 New Zealand Soil Classification - Hewitt
Keywords	Soils, classification, soil maps
Description	The New Zealand Soil Classification was developed in the 1980s. The new classification grew out of the old New Zealand Genetic Soil Classification and where possible preserved its useful features. It was developed because the old system had vaguely defined soil classes that made it difficult to identify the correct soil classes for many soils; and much new soil information could not be explained within the framework of the old system. The new classification system was also influenced by local experience in testing the United States soil classification system "soil taxonomy". The New Zealand Soil Classification has a hierarchical structure with four levels in the hierarchy: soil orders(15)-this is the most generalised level of the classification and provides the national overview of New Zealand soils soil groups(73)-the orders are divided into 73 soil groups based on variation in factors such is drainage status, parent material, chemical and physical properties subgroups(272)-the soil groups are divided into 272 subgroups which provide more detail about the range of soils included in each soil group soil forms-the soil subgroups are divided into soil forms which provide more detail about soil parent material, texture and permeability.
Original Purpose	The New Zealand Soil Classification is a national soil classification intended to replace the New Zealand Genetic Soil Classification. The new system was needed because modern soil surveys and land evaluations required that soil classes be precisely defined. In addition a new synthesis was needed for the large amount of information that had been collected since the 1950s. The new system preserved the successful parts of the New Zealand Genetic Soil Classification where possible. The objectives of the New Zealand Soil Classification are: to provide a better means of communication about New Zealand soils and their utilization to provide an efficient vehicle for soil identification, soil series recognition and correlation to enable an efficient stratification of soil database information to draw together knowledge of the properties of New Zealand soils and important similarities and differences among them (Hewitt,1998).
Status	Version 1 - 1984; version 2 - 1989; version 3 - 1993. Versions 1 and 2 were constructed from well characterized pedons, mainly from the national soils database. Version 3 was tested in a range of field situations and against many other data sets. Because the classification was developed from a subset of all possible variation of soils in New Zealand it is expected that future revisions will be necessary as more information is gained (Hewitt,1998).
Organisation	Landcare Research
Jurisdiction	New Zealand
Contact person/posistion	Alan Hewitt Scientist
Address	Manaaki Whenua-Landcare Research Private Bag 1930 Dunedin Phone +64 3 477 4050 Fax +64 3 477 5232 Email hewitta@landcare.cri.nz
Available format	Papers and publications
Access	Freely available
Geographical coverage	Nationwide

Operational Specifications
Scale of Operation	Wide range of scales -1:5 000 000 to detailed property plans
GIS Compatibility	Yes
Relationship between levels in the classification system	This is a hierarchical system with four layers (soil orders/ soil groups/ subgroups/ soilforms).
Contributing databases/ classification systems	N/A
Contributing database GIS compatibility	N/A
Relationship with other classification systems and spatial frameworks.	This system has evolved from the earlier New Zealand Genetic Soil Classification.
Relationship with other databases	A number of soil data sets were tested using the system in its developmental stages.

Current and emerging use for:
Assisting with determining historic state/ baseline	This soil classification can assist with a determination of historic state.
Assisting with determining current state/ baseline	This soil classification can describe the current state of the soil, especially when the full classification is used.
Asssisting with scenario building and modelling of possible futures	This soil classification can be used for scenario modelling.
Risk Assesment	The soil classification should be able to identify sites of high risk for particular activities
Monitoring site selection and sample design	This soil classification could be used for site selection.
Aggregating and reporting data locally, regionally and/or nationally	The classification system is hierarchical. It is possible to aggregate data up the levels in the hierarchy and also to scale data up. Reporting can be nationally, regionally or locally.

Current use (who,level,why)

The New Zealand Soil Classification is primarily being used by the scientific community. There is a relatively low level of use by land management agencies and personnel. This is because soil maps and descriptions have been made using the older New Zealand Genetic Soil Classification. As there now is no funding for soil mapping, few if any soil maps have been made using the new classification system.

User friendliness/public and decision maker understanding

Considerable effort was made when developing the new system to retain links with the New Zealand Genetic Soil Classification. Names are relatively user-friendly at the order level. The naming of lower levels in the hierarchy becomes more complex and difficult to understand.

Compared to the New Zealand Genetic Soil Classification the new system is not well known or used by the general public or land management agencies.

System strengths

The New Zealand Soil Classification is a precise system that allows detailed and accurate descriptions to be made for soils
The system is more internationally comparable than the New Zealand Genetic Soil Classification although it is still a New Zealand system only
The classification is a logical and hierarchical
There is extensive documentation about the classification system including the methodology used to construct the system
The classification system has been evolving as more information becomes available.

Current limitations of framework

There is a lack of public awareness about the new classification system
Tthere is little use of the new system by management agencies because there are few if any soil maps being made using the new soil classification system
There is no funding for soil mapping so it is difficult to see how the lack of soil maps will be addressed
The data from the old New Zealand Genetic Soil Classification cannot be directly transferred to the new system because the new system has more categories, is more specific and is field orientated.
The New Zealand Soil Classification has conceptually superseded the old system, however 95% of the published data uses the old system.

References

Hewitt, A. 1998. The New Zealand Soil Classification. Appendix: in Soils in the New Zealand Landscape-the living mantle. By Les Molloy. Second edition.

Hewitt, A.E.1993. Methods and rationale of the New Zealand Soil Classification. Landcare Research Science Series No. 2. 71p.

Hewitt, A.E. 1998. New Zealand Soil Classification. Landcare Research Science Series No. 1. Second Edition. Manaaki Whenua Press: Lincoln.133p.

Clayden, B; Webb, T.H. 1994. Criteria for defining the soilform the fourth category of the New Zealand Soil Classification. Landcare Research Science Series No. 3. 35p.

System Title