Coupled life cycle assessment and business modelling to estimate the sustainability of using regenerated soils in urban forestry as nature-based solutions

Using regenerated soils as a planting substrate in newly implemented green infrastructure is considered a circular economy-oriented strategy alternative to traditional ways of depriving fertile soils from agricultural lands, and/or applying fertilizers and soil conditioners. However, knowledge on the environmental footprint of regenerating and applying such excavation soils on urban brownfields is quite fragmented. This study aims to illustrate a coupled application of life cycle assessment (LCA) and business modelling to a pilot nature-based solution (NbS) implemented on a post-industrial area in Turin, Italy. This NbS is configured as urban afforestation intervention on 1,200 sqm where trees and shrubs are planted on a layer of excavation soil augmented with organic compost, zeolite powder and biostimulants, called “New Soil”. The rationale of combining LCA with a strategic management Business Model Canvas (BMC) is to identify the most relevant socioeconomic and environmental synergies and trade-offs associated with the potential upscaling of a New Soil NbS intervention in the market. On one hand, the use of LCA allowed to estimate the detrimental impacts generated along the entire supply-chain of the NbS implementation, as well as its environmental performances in comparison with hypothetical business-us-usual scenarios. On the other hand, results from expertbased surveys formulated with BMC provided the necessary (and complementary) knowledge for prospecting a sustainable pathway associated with the NbS deployment. It was observed that both life cycle upstream and downstream strategies of reducing environmental impacts can be implemented, which may help saving in between ~70% to more than 100% the environmental footprint compared to conventional resource consumption streams. The outcomes of this study are useful to prospect strengths and challenges that land managers need to address for possible deployment of New Soil NbS at large territorial scales.