RELEVANCE OF MICROCOSM AND MESOCOSM EXPERIMENTS FOR STUDYING SOIL ECOSYSTEM PROCESSES

The reliability of previously reported microcosm and mesocosm studies was tested by comparing the mean values of microbial respiration and enzyme activities and of the availability of macronutrients (K, Ca, Mg, NO3, NH4, PO4) from these studies with the same variables in the forest floor. The field data show the same trend as the microcosm and mesocosm measurements, viz. a buffering effect of soil arthropods on forest floor processes, and a stimulated nitrification resulting in a lowered ammonium and calcium, and a higher nitrate availability. The use of microcosms and mesocosms is discussed. It is concluded that they are valuable tools to unravel the intrinsic soil ecosystem interactions, but mesocosms in the field are preferred to laboratory microcosms.