A statistically based mapping of the influence of geology and land use on soil pH: A case study from Denmark

The purpose of this paper is to investigate the geographical distribution of pH values in Danish soils of different ages representing the main Saalian and Weichselian ice advances. The investigation is based on soil sampling from top- and subsoils in soil profiles located in a nationwide 7-km grid. The data have been analysed using statistical spatial analysis methods, and a model has been erected demonstrating areas of homogeneous low, high, or inhomogeneous pH values relative to deposits from different ice advances and regional variations in land use.The investigation shows that the major part of Jutland is characterized by low pH values in the topsoils and subsoils compared to the islands east of the peninsula. This corresponds with the maximum extension of the Weichselian Young Baltic Ice Cap. A Hot Spot analysis carried out on regional and local scales shows that most of the Danish islands form a homogeneous area of high pH values except Northeast Zealand. And in Jutland a huge area east and north of the maximum extension of the Young Baltic Ice Cap formed a homogeneous area of low pH values. Exceptions are the areas around Mors in the western part of the Limfjord and in the eastern part of Himmerland and on Djursland.

► pH distributions in Danish soils were investigated using spatial statistics.
► pH distributions are closely related to erosive characters of the ice advances.
► Large clusters of low pH values were found in western Denmark.
► Large clusters of high pH values were found in the north, east and south.