Effects of changed litter and water input, of clear cutting and a changing tree species composition on the dynamic of DOC and DON in soils

BITÖK-A11

From 01/2001 to 12/2004

Principal Investigator: Egbert Matzner
Staff: Karsten Kalbitz
Grant: 0339476 D Grundlagen zur nachhaltigen Entwicklung von Ökosystemen bei veränderter Umwelt

Dissolved organic carbon and nitrogen (DOC, DON) contribute significantly to the C and N cycle in terrestrial ecosystems. It is the objective of the project to identify and to quantify important controls of the DOC/DON dynamic in soils of coniferous and deciduous ecosystems under field conditions. The main part of this project comprises field experiments with a manipulation of litter and water input and a changed tree species composition after clear cutting. DOC and DON concentrations and fluxes are analysed in the forest floor and in the mineral soil. The effects of the changed controls (litter, water, tree species) on the humification degree of dissolved organic matter will be determined by spectroscopic methods (UV, fluorescence). The analysis of stable C and N isotopes will enable to identify a changing C and N turnover and differences in the dynamic of DOC and DON. In addition to the field based approach a combination of field and laboratory experiments will be conducted to study the relations between the decomposition of litter and the amount and composition of dissolved organic matter.