Mapping and describing natural terroir units in Denmark

Abstract

A natural terroir unit is a tract of land whose natural characteristics form a unique assemblage of factors (soil, terrain and climate) which together impart specific high-quality characteristics to an agricultural product. In order to map and describe Danish natural terroir units, we built on previous efforts to quantitatively map and describe Danish natural terroir units based on soil, terrain, climatic and historical crop yield data. Our work consists of four stages: (1) The OSACA algorithm was applied to define soil centroids and measure taxonomic distance between soil profiles and soil centroids based on a Danish soil spectral library; (2) nine Danish terron classes were established by fuzzy c-means clustering based on soil, terrain and climate information; (3) a Danish terron map was generated by Cubist regression tree models and the uncertainty of this map was assessed by a terron membership map; (4) Danish natural terroir units were described by linking historical crop yield data to the terron map. The results suggested that the OSACA algorithm and Vis-NIR spectral data could be used as an efficient tool to facilitate terron identification. The terron predictions also showed that the addition of terrain and climatic predictors improved the previously created Danish terron map. The description of Danish natural terroir units showed that seven natural terroir units could be an optimal number for Denmark for specific crop types. Further investigations are needed that link more agricultural yield data to this terron map in order to describe natural terroir units for different agricultural products. The methods developed in this study could be tested in other countries to facilitate sustainable soil management and minimize environmental risks.