By: Andy von Heßberg
Installation of soil-plant mesocosms in Bayreuth
The mesocosms have been installed within several days in September 2016 into the built raised beds. First, the mesocosms have to be protected against lateral plant competition (which would bias the future results); secondly, they have to be protected against frost and drought as they would if they were buried in their natural setting. We couldn’t install them in the ground at Bayreuth experimental site because of the high ground water level there. So we decided to build these raised beds. The woody beams are protected by the contact with soil by a special plastic layer. On the bottom is gravel for frost-protection. Directly on this, the mesocosm-cylinders are placed. The spaces in between the cylinders are filled with normal local soil. The mesocosms, which originate from different sites (Fendt, Graswang, Esterbergalm, Bayreuth) are installed together in a randomized design. Normally there are 15 mesocosms in one raised bed. There are 9 raised beds, so that we have an opportunity for future treatments (e.g. drought, more rain, influence on the composition of grasses vs. herbs, etc.).