Spatial surface estimates of soil carbon stock (units tonnes per hectare) for the 0–30cm layer, over the land surface of New Zealand, based on a generalised linear regression model using environmental classification, national soil layer, and climate layers as explanatory variables, with a correction for spatial auto correlation of data samples. 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 soil carbon stock across the area occupied by each grid cell. A number of data layers were acquired to act as explanatory layers for the prediction of soil carbon. Soil data includes the MfE Historic Soils Database (under an agreement with MfE), the NSD (LandcareResearch New Zealand 2012), the SINDI soil quality dataset (Landcare Research New Zealand 2012), and the LMI soils dataset (under an agreement with Plant and Food Research 2011).Additional explanatory data layers were obtained from the LENZ data set (Landcare Research New Zealand), including the LENZ climate layers (e.g. mean annual rainfall) as well as environmental classification layers (LENZ level 1, 2, 3, and 4), from the Koordinates data portal (Koordinates 2012). In addition, the natural potential vegetation layer (Leathwick 2001) is used as an indicator of vegetation prior to agricultural development. These layers were augmented by explanatory layers acquired from the LRIS portal (Landcare Research 2012), consisting of national maps of basic soil properties (soil order, exchangeable calcium, acid soluble phosphorus, rock class, mid-estimate of surface outcrops, annual water deficit). Additional 0–30cm carbon stock data was obtained by using SINDI data (derived from 0–10cm depth samples) along with NSD data and a regression model to infer 0–30cm soil carbon stocks (tonnes/ha) at the centre of each pixel. This data is owned by the Ministry of Primary Industries (MPI)).
Estimate of soil carbon stock in 2012 (units tonnes per hectare) for the surface layer to a depth of 30 cm.