1 Aligning New Zealand digital soil mapping with the global soil mapping project

New Zealand is undertaking a new phase of soil mapping (S-map) with the goal of national soil map coverage at 1:50 000 scale. One S-map objective is to develop a national capability in digital soil mapping (DSM). Concurrent development of the global soil map (GSM) project provides an opportunity for the S-map project to align its work with the GSM initiative both to achieve an enhanced national soil map and contribute New Zealand data to the GSM project. Consequently we have applied GSM method guidelines nationally. We matched the generic GSM methods to 193 New Zealand soilscapes. Soilscapes with similar levels of legacy soil information were grouped into eight soilscape groups, and DSM methods applied to them. Four soilscape groups were in low relief land where intensification of land use generates high demand for new soil information. The other four method classes were in rolling, hilly and mountainous land. The most extensive method in low relief land requires establishment of better environmental covariate layers followed by soil map reference area extrapolation, and the most extensive method in high relief land involves sampling programmes and scorpan analysis. The proposed inference engines are Bayesian belief networks