2.2. Soil Samples
At each 1 m2 sample point the leaf litter was removed and approximately 1 kg of soil was cut from the top 20 cm using a small spade and knife and divided into five 200 g samples. Samples without plant debris and stones were placed in plastic bottles and cooled for transport. Soil was homogenized manually by thorough mixing. Soil samples were then frozen at −20°C. All tools and materials used were washed and sterilized [15].