We investigate how water in soils of near-natural ecosystems like forests react to air pollution, climate change or forest management operations. Thus we provide a basis for decision-making for politicians and forestry specialists, e.g. when establishing groundwater protection zones or evaluating political measures for environmental protection.
Water contained in the pore space of soils, often called soil solution, is essential for the growth and the vitality of plants and soil organisms, because it supplies nutrients to them. Water in forest soils is also important for humans, since groundwater from forested catchments is usually of good quality and therefore is often used as drinking water.
However, air pollution leading to acid atmospheric deposition, increased atmospheric nitrogen input or elevated carbon dioxide concentrations can alter the nutrient cycling and the functioning of near-natural ecosystems and, as a consequence, the quality and the quantity of soil water. Climate change such as warming or an increased frequency of extreme meteorological events can also affect soil water quality and the quantity of soil water available to plants.
Human activities such as silvicultural practices can modify soil water quality and soil water regime either positively e.g. by a suitable selection of tree species to improve soil quality or negatively e.g. by soil compaction because of the use of heavy harvesting machines resulting in tree regeneration problems.
These anthropogenic influences affecting the cycling of nutrients and water in near-natural ecosystems can threaten important soil functions like storage of water and nutrients or buffering and filtering of atmospheric deposition.
Understanding chemical and physical processes
Combining long-term monitoring, field and laboratory experiments and modelling, our research activities aim at:
- a better understanding of carbon and nutrient (N, P, Mg, K, Ca) dynamics in soils and in particular in the root zone of near-natural ecosystems.
- assessing the responses of soil water (quality and quantity) in near-natural ecosystems to climate change and to air pollution, focusing on the acidification of soil water and the leaching of nitrate and DOC from forest soils.
- determining the impact of heavy harvesting machines on the soil water regime and at assessing the compaction sensitivity of different forest soils.
- determining the effects of tree roots on the soil water regime, e.g. by studying how indigenous dominant trees species (e.g. spruce, fir, beech) influence soil water movement and storage with their specific root systems.
These investigations provide important data for environmental policy makers to implement international agreements (e.g. Convention on Long-range Transboundary Air Pollution, Kyoto protocol, The Paris Agreement) or to monitor the effects of environmental measures. They also help forestry professionals to improve the management of forested areas to ensure the supply of clean drinking water and to protect against floods.