Surface runoff can transport dissolved phosphorus into surface waters. Grassland areas that have been heavily enriched with phosphorus and fertilised with liquid manure are particularly problematic.

Research project evaluation of strongly contributing areas on Lake Baldeggersee

The agriculture and forestry service (‘lawa’) of the canton of Lucerne has created a concept for the development of ‘phosphorus projects Phase III’ in close partnership with the FOAG and FOEN, in order to renew the existing Phosphorus Project according to GSchG [=Water Protection Act’] Art. 62a.

The research project conducted concurrently has delivered the following results:

The multi-year measurements of the P loads in the brooks show that the diffuse inputs (surface runoff, tile drainage, leaching, atmospheric deposition on surface waters, farmyard runoff, etc.) still constitute the main sources of algae-stimulating P inputs in Lake Baldegg. The soils in the catchment area of Lake Baldegg have excessively high P levels. A drastic reduction of soil P is therefore necessary in order to reduce diffuse inputs. This can only be achieved through a significantly reduced P input on agricultural land. In addition, it is recommended that any heavily loaded drainage systems be examined and improved in the event of excessive P load.



Sebastian Stoll, Cäcilia von Arb, Volker Prasuhn