Databases - Soil Fundamental Data Layers (FDLs)
FDLs contain spatial information for 16 key soil attributes. Each attribute is measurable (i.e., is given a numeric value rather than being assigned to a descriptive class or category) and is recorded in appropriate units of measure. Because attributes have measurable values, FDLs are particularly useful in computer modelling and have enabled researchers and resource management decision-makers to make the most of rapid developments in GIS technology.
The 16 key soil attributes were selected through the consultation process with stakeholders, and generally fall into three groups: soil fertility/toxicity, soil physical properties particularly those related to soil moisture, and topography or climate (T). Parameters include slope, potential rooting depth, topsoil gravel content, proportion of rock outcrop, pH, salinity, cation exchange capacity, total carbon, phosphorus retention, flood interval, soil temperature, total profile available water, profile readily available water, drainage, and macro?pores (shallow and deep).
Regional soil databases were the key to generating the soil FDLs. New Zealand was subdivided into several geographic regions and soil scientists were allocated a region for which they developed a "regional legend" (regional database). Regional data was correlated using the New Zealand Soil Classification (NZSC), referenced to the NSD and other relevant data sources, and then linked to the soil polygons in the NZLRI.