Collection and analysis of soil
Half a kilogram of soil was collected from each of five locations in
Mecklenburg-Western Pommerania, Germany (see Figure 1). The soil types
chosen (yard soil, two kinds of forest soil, swamp mud and beach sand)
were based on locations where wild boar are commonly found. In addition,
a bag of commercial potting soil was purchased to have a more controlled
matrix with neutral pH, compared to the acidic forest soil samples
collected (see Table S1 in the supplemental material), and sterile sea
sand was obtained from a lab supplier (Carl Roth, Karlsruhe, Germany).
The collected soils were analysed by an agricultural laboratory in
Rostock, Germany (Landwirtschaftliche Untersuchungs- und
Forschungsanstalt, LUFA) (see Table 2 in the supplemental material).