Project description C3a
Scientific advisors
Prof. Dr. F. Beese, Dr. M. Jansen
Project
Analysis and modeling of the soil phosphorus and the nutrient balance of a temperate beech-forest ecosystem
The foliar phosphorus concentrations of many German forest trees indicate deficits in phosphorus nutrition. The low status and availability of phosphorus in soils can be explained by acidification of forest soils and high atmospheric N depositions.
This project investigates the status, turnover, and transport of soil phosphorus and the phosphorus balance of a mixed-beech forest ecosystem with differing tree diversity.
The concentrations and pools of total, inorganic and organically bound soil phosphorus are measured and the turnover of phosphorus entering the soil system annually with the leaf and herb layer litter and the fine roots is assessed.
For the quantification of organically bound phosphorus near infrared spectroscopy is calibrated and validated with data obtained by the ignition loss method.
Furthermore, the amount and kinetics of phosphate ad- and desorption are determined and phosphate transport parameters are modelled (CXT-Fit) from experimentally obtained breakthrough curves.
The input of phosphorus (and other nutrients) into the forest ecosystem with rainfall is measured and the output through seepage water is modelled (Expert-N). Following, the phosphorus (nutrient) balance of the studied forest ecosystems is calculated.
Methods
- P-extraction methods (Bray, Olsen, dest. H2O, H2SO4)
- Ignition loss (quantification of organically bound nutrients)
- NIRS (near infrared spectroscopy)
- Soil water sampling with suction cups (lysimeters)
- Sorption isotherms
- Breakthrough curves
- Modelling: CXT-Fit (soil phosphorus transport) and Expert-N (soil water balance)