S-map expands further and reaches 11 million hectares!

Last year closed out with a significant achievement for S-map, New Zealand’s comprehensive online resource soil information system. In the latest update to S-map Online, released in August 2024, the coverage of S-map reached 11 million ha, or 73% of the multiple-use land (Land Use Capability classes 1 to 4).

Through a funding collaboration between the Ministry for Primary Industries, the Ministry for the Environment, and 12 regional councils, Manaaki Whenua – Landcare Research has completed an extra 507,000 ha of new soil mapping coverage across some of New Zealand’s best food-producing land. A further 363,000 ha of legacy mapping was replaced with a new soil survey. The partnership is on track to deliver a further 700,000 hectares of new mapping over the next year.

The newly mapped areas in this update to S-map include:

201,660 ha in Wellington – Wairarapa east coast
9,656 ha in Marlborough – upper Wairau River valley
27,655 ha in Tasman – Tapawera valley and Moutere River valley
64,625 ha in Otago – Moa Flats
45,999 ha in Southland – Chatton (north of Gore) and Curio Bay, Catlins
158,000 ha in Northland – Kaikohe, Dargaville and Pouto Peninsula.

Updated mapping of lower-quality legacy mapping includes:

123,698 ha in Bay of Plenty – Kaituna and Maketu water management areas
240,000 ha in Tasman – Motueka hill country.

Pedologist Emily McKay, who led the Northland soil survey with senior researcher Dr Scott Fraser, highlights the highly interesting and variable soil types we are mapping across New Zealand. ‘We encountered the famous Kerikeri Oxidic soils, and Allophanic soils formed on young basalt flows, both really valuable for horticulture,’ says Emily. ‘The most interesting feature so far among many of the Ultic and Podzol soils is the presence of a silica-rich layer that makes your auger squeak and spin in circles, and they are some of the most difficult soils for farmers to manage.’

A gallery of some of the fascinating soils we have mapped across our different surveys over the last year is presented in the figure below.

1. A Pan Podzol soil formed in old sand dunes (Awhitu sandstone), which are between 1.2 and 1.6 million years old, found on the Poutu Peninsula, Northland. Image — 1. A Pan Podzol soil formed in old sand dunes (Awhitu sandstone), which are between 1.2 and 1.6 million years old, found on the Poutu Peninsula, Northland.

2. An Orthic Allophanic soil formed on the base of a young basalt scoria cone, found in the mid-North between Kaikohe and Kerikeri. Image — 2. An Orthic Allophanic soil formed on the base of a young basalt scoria cone, found in the mid-North between Kaikohe and Kerikeri.

3. An Orthic Brown soil found on the younger stony terraces of upper Motueka River valleys. Image — 3. An Orthic Brown soil found on the younger stony terraces of upper Motueka River valleys.

4. A Firm Brown soil found on the older high terraces with clay-bound subsoil gravels in the upper Motueka River valleys. Image — 4. A Firm Brown soil found on the older high terraces with clay-bound subsoil gravels in the upper Motueka River valleys.

5. A Firm Brown soil formed in wind-blown loess over deeply weathered mudstone in the valleys of the Catlins. Image — 5. A Firm Brown soil formed in wind-blown loess over deeply weathered mudstone in the valleys of the Catlins.

6. A Sandy Brown soil formed in relatively young sand dunes on the south coast of the Catlins. Image — 6. A Sandy Brown soil formed in relatively young sand dunes on the south coast of the Catlins.

Developed and updated by Manaaki Whenua – Landcare Research, S-map provides the best available soil survey data for New Zealand. It displays basic soil property data such as depth, stoniness, and clay content, as well as more complex data such as water-holding capacity and nitrogen-leaching risk, and provides comprehensive and accurate soil information to support the sustainable management of our soil resource. There are also tools that help land managers and consultants find the S-map soil type that best matches on-farm field observations.

Soil scientist Dr Sam Carrick says richer soils data mean much better modelling assumptions, which in turn support better decision-making on the ground. ‘A major focus has been the provision of soil hydrology information, soil attributes that have significant effects on farmers’ nutrient budget calculations,’ says Sam. ‘More accurate soil moisture information will lead to better knowledge of irrigation demand and nutrient losses.’