Browse Data

Estimates of soil phosphate retention (P-retention; units: %) for the depth interval between 0 to 7.5 cm, covering all of New Zealand. Estimates are made on a grid where each grid cell has dimensions 1,000 m x 1,000 m (100 ha). The value at each grid cell is our best estimate of the mean P-retention across the area occupied by each grid cell. The layer was generated using a quantile regression forest which was fitted using a number of environmental datasets including soil parent material, topography and climate layers. Saunders WMH 1965. Phosphate retention by New Zealand soils and its relationship to free sesquioxides, organic matter, and other soil properties. New Zealand Journal of Agricultural Research 8(1):30–57. doi:10.1080/00288233.1965.10420021

This layer shows the coverage of S-map polygons, labelled with their Soil mapunit – a unique identifier of one or more polygons with the same soil information.
The S-map primary map layer of soil classes (i.e. delineated areas that are labelled with the soil family names) is no longer freely available to commercial users. Access to this data and associated soil attribute data for commercial use is by negotiation - contact Graeme Anderson (andersong@landcareresearch.co.nz).

ACCESS to publicly available S-map data is now at
Smap Soil Depth
Smap Soil Drainage
Smap Soil Texture
Smap NZ Soil Classification
Smap Nitrogen Leach Risk
Smap Relative Bypass Flow

NOTE: There has been a change in the way the S-map is being made available to users. The S-map primary map layer of soil classes (i.e. delineated areas that are labelled with the soil family name) is no longer freely available to commercial users. Access to this data and associated soil attribute data for commercial use is by negotiation - contact Graeme Anderson (andersong@landcareresearch.co.nz).

ACCESS to publically available S-map data is now at

S-map Soil Depth

S-map Soil Drainage

S-map Soil Texture

S-map NZ Soil Classification

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S-map's primary map layer is soil classes, i.e. delineated areas that are labelled with the soil family name. Each soil family is defined as a unique combination of attributes (NZSC classification, parent material, rock type, dominant texture and permeability class). Soil classes are further characterised as siblings according to their depth to rock class, stoniness, land type, drainage, texture (more detailed), functional horizons and miscellaneous variant information. The uncertainty of each of these family and sibling attribute classes is specified. Associated with the soil class layer will be additional map layers of fundamental and derived soil properties. The fundamental soil properties are depth (diggability), depth to slowly permeable layer, rooting depth, rooting barrier, horizon thickness, stoniness, clay and sand content. They are developed from sample information and expert knowledge. The derived soil layers are each based on a model (or pedo-transfer function). Some models are simple lookup tables that depend only on the soil class. Others combine various soil, land use, vegetation, climate or topographic attributes in a mathematical formula. Derived layers will include available water (mm), macroporosity, water retention, bulk density, total carbon, total nitrogen, phosphorus, calcium, cation exchange capacity, pH, and phosphorus retention.

Spatial estimates of gravimetric soil carbon (%) for the 0–7.5 topsoil layer, over the land surface of New Zealand. It was derived using gradient boosting regression from a range of environmental classification, national soil classification, and climate layers as explanatory variables.

The model was calibrated on a large number of samples (approx. 17,000 laboratory samples) assembled from a range of different soil science projects, including data in the National Soil Repository Database (NSDR), the Land Management Index (LMI) dataset, and the GNS geochemical baseline dataset.

Estimates of soil carbon are made on a grid where each grid cell has dimensions 100 m x 100 m (1 ha). The value at each grid cell is our best estimate of the average soil carbon percent at the centre point of each grid cell.

The susceptibility of the soil to nitrogen leaching - the process whereby excess nutrients not held by the clay and organic matter complex of the soil leach beyond the root zone and contaminate groundwater. The susceptibility rating is based on the capacity of the soil to store water and the attenuation of nitrogen through denitrification associated with anaerobic conditions. It does not take into account the climate or land use but is limited to the effect of the soil characteristics. Please refer to document Smap Data Dictionary Dissolved Layers.pdf at lris.scinfo.org.nz/document/22129-smap-data-dictio...

Relative bypass flow is the potential susceptibility of water infiltrating at the soil surface to bypass the soil matrix as it drains through the soil. This is where the infiltrating water rapidly ‘short circuits’ the soil by percolating along preferential pathways (i.e., macropores, cracks, fissures, decayed-root channels). The vulnerability of land to bypass flow is based on soil classification, soil structure, and soil attributes that promote ponding. It does not take into account climate or land use. Please refer to document Smap Data Dictionary Dissolved Layers.pdf at lris.scinfo.org.nz/document/22129-smap-data-dictio...

Soil depth is defined according to a traditional agronomic concept of soil depth (Webb &
Lilburne 2011). Note that while the layer defining soil depth may cause some restriction in root penetration, it does not necessarily define the base of the potential rooting depth. This layer is a "dissolved" representation of the soil depth attribute for S-map soils, where neighbouring S-map polygons have been combined if they have the same value of the attribute. Refer to document Smap Data Dictionary Dissolved Layers.pdf at lris.scinfo.org.nz/document/22129-smap-data-dictio...

NZSC Order is the first level of the NZ soil classification (Hewitt, 2010). This layer is a "dissolved" representation of the NZSC soil order attribute for S-map, where neighbouring S-map polygons have been combined if they have the same value of the attribute. Refer to document Smap Data Dictionary Dissolved Layers.pdf at lris.scinfo.org.nz/document/22129-smap-data-dictio...

Soil drainage is a relatively simple classification of the soil profile that describes the likelihood of seasonal wetness (Webb & Lilburne 2011). It is based on the occurrence within specific depths of redox segregation and low chroma colours indicative of waterlogging and reduction (Milne et al. 1995). This layer is a "dissolved" representation of the soil drainage attribute for S-map soils, where neighbouring S-map polygons have been combined if they have the same value of the attribute. Please refer to document Smap Data Dictionary Dissolved Layers.pdf at lris.scinfo.org.nz/document/22129-smap-data-dictio...

Soil texture is the dominant texture class in the control zone (usually the upper 60 cm) of the soil profile as defined in Webb & Lilburne (2011). This layer is a "dissolved" representation of the soil texture attribute for S-map, where neighbouring S-map polygons have been combined if they have the same value of the attribute. Refer to document Smap Data Dictionary Dissolved Layers.pdf at lris.scinfo.org.nz/document/22129-smap-data-dictio...