A seeding test on the spoil field Radelsee was installed in preparation of the test dike construction in the summer 2011. It includes three test fields (each 3 m²) with selected dredged materials to investigate the turf development. The Steinbeis Innovation gGmbH is responsible for the realization and control of the tests.

The seeding test considers three different variants. Variant one includes a standard seed mixture for dikes. Variant two additionally iplies an admixture of legumes. In the third variant the self-greening of the dredged materials is tested. The partially existing vegetation on the chosen dredged material heaps, which provide also the material for the test dike construction, was taken off. Three tripartite parcels of 3 m x 1 m (each variant 1 m²) were prepared. The parcels were framed and irrigated with 10 l/m².

Seeding Test

After the water was infiltrated into the top soil, the seed mixture with 30 g/m² was distributed.

The standard seed mixture for dikes DSV 900 was used. The mixture includes red fescue Festuca rubens (60%), perennial ryegrass Lolium perenne (30%) and kentucky blue grass Poa pratensis (10%). The second variant includes an admixture of the legumes white clover Trifolium repens (6%) and lucerne Medicago sativa (3%). Accordingly the amounts of the grasses were reduced. The mixture DSV 900 supports the erosion control of the dike cover through fast and permanent greening. Red fescue is salt tolerant and provides a dense turf. The second mixture with addition of legumes shall provide a further advantage for the surface strength and a fast greening. Moreover the white clover and the lucerne provide an additional nitrogen source and ensure the conservation through a fertilizing effect.