Aggregate stability of cultivated vineyard soils with high rock fragment content in the Mosel area, Germany

Within the European project Diverfarming (Horizon 2020, no 728003), which investigates crop diversification and low-input farming across Europe, we study the aggregate stability variability of soils with high rock fragment content on steep sloping vineyards in the upper Saar valley of the Mosel area (Wawern, Rhineland-Palatinate, Germany).

In the framework of the case study researched by Trier University and their partners, aromatic herbs (Oregano and Thyme) are planted in rows underneath the grapevines to minimize soil erosion, suppress unwanted weeds and to be harvested for further use. Additionally, this cultivation affects different soil characteristics such as aggregate stability.

We analyse the aggregate stability using and comparing three different methods:

• wet sieving which is executed in two different ways – slaked and rewetted treatment,
• percolation method and
• single drop technique.

Aim of the study is to understand the effect of soil treatments underneath the grapevines, and to identify the method(s) being able to quantify the differences best.

Regarding the different methods, first results indicate that the quantified aggregate stabilities of each method are comparable. With this, we could identify differences between uncultivated rows (control areas), and the rows intercropped with aromatic herbs. In the latter ones, the aggregate stability underneath the grapevines is affected positively. Furthermore, there is a clear difference between slaked and rewetted treatment within the wet sieving method, where less stable aggregates are isolated.

The results indicate that the accomplished management (vine intercropped with Oregano and Thyme) improves the aggregate stability and therefore it improves the soil quality in general.