Science to underpin stewardship of New Zealand’s highly productive land
New Zealand is internationally renowned for its high soil diversity. Although our national soil survey, S-map, is only halfway through mapping the soils of New Zealand, already over 5,500 unique soil types have been identified. Think of the sub-tropical clay soils of Northland, the volcanic ash soils of Taranaki and Waikato, or the stony, glacially derived soils in Canterbury and Central Otago.
Within this great variety of soils, not all soils are equal, and some are more versatile than others for supporting food production. In New Zealand the relevant capability of different areas of land are evaluated through the Land Use Capability (LUC) classification system, which at its highest classification level assigns areas of land to one of eight LUC classes. LUC class 1 is the most versatile land, whilst LUC class 8 (i.e. conservation or mountain lands) is the least versatile.
The New Zealand Government has just released a significant policy to protect the most versatile soils and land from ongoing urban sprawl and rural residential developments. The National Policy Statement for Highly Productive Land (NPS HPL) will come into effect from 17 October 2022.
The NPS HPL recognises highly productive land as belonging to LUC classes 1 to 3, which in its original state comprised around 14% of New Zealand. However, the Our Land 2021 national state of the environment report highlighted that significant areas of HPL have been lost to urban sprawl and rural residential developments, with a large amount lost in the past 20 years alone.
Manaaki Whenua – Landcare Research, in collaboration with the Ministry for the Environment, Stats NZ and Waikato Regional Council, has developed a new environmental indicator for HPL. This indicator monitors the effects of land fragmentation on HPL availability for land-based production. Land fragmentation is the subdivision of land into smaller parcels, through activities like subdivision and residential development, including expansion of urban areas.
In order to enable easier access to LUC-related information, Manaaki Whenua – Landcare Research is also in the process of establishing a new web portal which will hold all relevant documents for interpretation and use of the LUC. This portal is expected to be launched by mid-2023.
- Specifics on the NPS-HPL policy can be found here.
- 'Baseline Highly Productive Land' layer on OurEnvironment; this is a visualisation of the baseline extent of Highly Productive Land across New Zealand, represented here as Land Use Capability classes 1, 2 and 3, as mapped in the New Zealand Land Resource Inventory.
- LUC dataset for download on the LRIS portal
- A full description of the land fragmentation indicator is available here by Stats NZ.
- A brief summary of the science underpinning this indicator is available in our Soil Horizons newsletter.