Blatten tests seed mixes as first greenery appears on debris cone

Researchers in Blatten, Valais, are testing seed mixtures to restore vegetation on the debris cone, with the first results showing that all eight mixtures have begun to grow, SRF reported.

The tests are being conducted on three plots, each covering half a hectare. The ground was first processed with a stone crusher and mixed with manure or soil. The aim is to determine which mixture grows best in each location.

Each mixture contains different combinations of clover species, herbs and grasses. Two weeks after sowing, all the tested mixtures had sprouted, although growth varied in strength. The results indicate that the plots can generally be restored. Plants are developing better where the ground was prepared more carefully.

The long-term goal is to use the debris cone as meadow or pasture. Arable farming is not considered feasible for the foreseeable future. Potato cultivation, for example, requires 20 to 30 centimetres of ploughable topsoil, while building up humus here would take generations.

Nutrient levels remain a challenge. The debris contains too little nutrient-rich material, particularly nitrogen, causing some of the first plants to turn yellow. The land will now be fertilised selectively, but this must be done carefully to prevent nutrients from being washed away.

Restoring the area is also costly. The ground must be prepared with specialised machinery, mixed with soil and organic material, and then irrigated. Costs were initially estimated at 60,000 Swiss francs per hectare, but Manfred Bötsch, who is responsible for restoring the debris cone, said that estimate was too low.

Experts plan to assess by autumn which seed mixtures are best suited for long-term use. According to plans by the Valais State Council, large-scale restoration is scheduled to begin in 2027 and 2028.