Research project on understock greening

Targeted seeding of ground cover in the area beneath the vine can keep unwanted weeds at bay. Currently, the Rural Area Service Center (DLR) Rhenish Palatinate, in collaboration with the University of Bonn, is investigating—as part of an FDW research project—whether and to what extent groundcover planting beneath the vines is a suitable alternative to chemical and mechanical methods.

Understory vegetation is intended to contribute to the enhancement of the vineyard ecosystem by replacing conventional methods of keeping the understory clear, as follows: The creation of new habitats and food sources increases biodiversity. Cover crops (in the area beneath the vines) help maintain soil fertility. Their roots also loosen the soil and improve its structure, thereby increasing water infiltration and storage capacity. Soil cover reduces the risk of soil erosion, silting, and compaction, especially during heavy rainfall. At the same time, compared to an open system, covered soil can better regulate soil temperature and moisture and reduce unproductive evaporation at the soil surface.

In times of the climate crisis, which is accompanied by rising temperatures and more frequent extreme weather events, the listed benefits of under-vine vegetation appear promising. However, it is important to note that vegetation in the understory can compete with the vines for water and nutrients, and if it grows excessively, it can negatively affect the microclimate in the grape zone and thus the health of the grapes. Furthermore, depending on weed pressure and climatic conditions, it can be very difficult to establish ground cover in the area beneath the vines.

The suitability of groundcover plants as an alternative weed control measure is being evaluated in greenhouse and field trials through vegetation surveys, plant and soil analyses, measurements of soil moisture and temperature, and examinations of the vines. The goal is to be able to recommend the seeding of specific plant species in the area beneath the vines, depending on the site and the feasibility of mechanical implementation. If successfully established, these plants can replace mechanical soil cultivation beneath the vines and the use of herbicides.