Organic soil amendments are increasingly being recognised as effective tools for restoring degraded soils, particularly in Mediterranean regions where climatic conditions accelerate the depletion of organic matter and increase the risk of desertification.

Waste-derived materials represent a sustainable option that could be adopted within a circular economy framework. The application of these materials can improve soil properties and facilitate spontaneous plant recolonisation. However, an integrated assessment of the ecological effects on biotic communities is required. Among them, arbuscular mycorrhizal fungi (AMF) play a crucial ecological role by acting as a functional bridge between soil and roots, supporting underground biodiversity and ensuring the recovery of ecosystem functionality.

This study, conducted as part of the EMBRACE Project of National Interest (PRIN 2022 PNRR), aims to evaluate the short-term effectiveness of four organic soil amendments in promoting spontaneous renaturalisation of soil in a Mediterranean quarry. The treatments include a vermicompost derived from marine waste and a stabilised sludge-based amendment, as well as variants of these enriched with natural zeolites, compared to an untreated control.

Herbaceous plant communities were studied by estimating the three components of biodiversity (species richness, composition and evenness), as well as the relative abundances, based on the number of individuals, dry biomass and cover measured according to the Braun-Blanquet scale. The structure and diversity of AMF communities were also investigated using a high throughput sequencing approach.

The results obtained at the nine-month from the amendment provide an overall picture of the effectiveness of the various treatments in guiding renaturalisation processes and modulating the biodiversity of the communities under investigation. The data highlight specific responses that allow the short-term effects of the treatments on the plant component and mycorrhizal community structure to be evaluated and discussed, with a view to the integrated restoration of the soil-vegetation system.