Studies on soil organic matter dynamics are being performed on vegetated and bare plots of different age established on the experimental fields in both study regions at different times of the year (spring, summer and autumn). The samples are submitted to structural analyses, and total organic carbon and nitrogen, microbial biomass, mineral nitrogen as well as various carbon fractions are determined in two soil depths (0-30 and 30-60 cm). Within the whole project period, more than 1.000 soil samples will be analysed in order to obtain time series of soil carbon turnover. In addition, an IRGA CO₂ analyser will be used to follow up soil CO₂ respiration.

For a more detailed regional characterisation of soil organic matter, nearly 1.000 soil samples will be taken from an area of about 950 km² in the Kraichgau and Central Swabian Alb and analysed for various carbon fractions. Regional maps of soil organic matter will be produced from these data sets and used for regional soil modelling.