Practical findings on legume catch crops before corn

The quasi-permanent ground cover provided by (legume) catch crops is a key climate adaptation strategy in the Upper Rhine Valley. It protects against extreme weather, reduces nitrate leaching over winter, and increases soil fertility through N and P efficiency, humus formation (C storage), and the promotion of biodiversity. This strengthens climate resilience, protects groundwater, and ensures sustainable agricultural yields.

In the Interreg project KLIMACrops, in collaboration with the Hochschwarzwald District Office, we investigated 

• the establishment of maize in perennial legume cover crops (colorful crown vetch) and
• the N and P efficiency of grain maize after variable cover crops (annual reseeding in autumn) 

at our Rinkenbergerhof field trial station and the Freiburg, Keidelbad site.

Among other things, it was shown that:

• colorful crown vetch is not suitable for practical use due to its lack of suppression power and slow establishment,
• wick rye (a green manure mixture of rye and hairy vetch) is a preferable option to maize in dry, warm locations (focus: soil fertility instead of N fertilization), and
• soil physical advantages (infiltration) can outweigh the water consumption of the cover crop.

For more information on the trials, see the poster (available for download below, German version only).