Exploratory analysis and a stochastic model for humusdisintegration.

Ulrich (1981) supposes in the hypothesis of humusdisintegration that the balance between polymerisation and breakdown of organic material may be disturbed in chemically well buffered European forest soils. This new aspect of aluminium toxicity may cause nitrogen exceedance in forest ecosystems and subsequent seasonal nitrate output (Eichhorn and Hutterman, 1999). In a research program the substances in the seepage water are monitored in a small woodland in central Germany. We explore these multivariate data for examining possible influences on the process of humusdisintegration and its temporal evolution. As a result, a regression model for carbon is developed, which includes covariables, i.e., other substances, as well as spatial and temporal terms describing systematic variability. Especially iron and aluminium turn out to be very influential in the model. So far our work is a basic step for monitoring the seepage water data by means of stochastic modelling.