Zoom into Soil: HS2

Welcome to the Zoom into Soil: HS2 video from the British Society of Soil Science.

Our first speaker is Chris Cantle, a Land Quality Principal at Jacobs, who presents ‘Colne Valley Western Slopes: Harnessing Soil Science to help maximise habitat creation’. The Colne Valley Western Slopes (CVWS) is one of the largest and most significant environmental projects on the HS2 Phase 1 route, being delivered by the Align JV. The design solution will deliver a dynamic landscape of tree-lined ridges, wood pasture and wetland set within extensive areas of species-rich calcareous grassland, with the 140ha site accessible from over 4 km of new recreational routes. Chris discusses how soil science has been central to optimising the design and sustainable materials reuse, including a series of innovative laboratory and field trials.

Our second speaker is Chris McCloskey, a Research Fellow at Cranfield University, who presents ‘Optimising soil profiles to support calcareous grassland habitat creation’. Calcareous grasslands are highly biodiverse and among Europe’s most floristically-rich habitats. These habitats are, however, threatened, and many of the UK’s calcareous grasslands were lost to changing land use during the 20th century. As part of the HS2 environmental works to ensure no net biodiversity loss along the route, 90 hectares of calcareous grassland will be created in the Colne Valley. Challenges to achieving high quality calcareous grassland were identified prior to construction, including variable soil calcium carbonate levels, elevated phosphate levels and the slow permeability of the chalk tunnel arisings which will underlie around half of the site. Chris and the team are therefore undertaking a series of glasshouse and field trials to explore how we can optimise the use of site-won soils and the reuse of HS2 construction by-products (limestone and concrete) for creating soil profiles which can provide the specialised soil chemical, physical and biological properties needed to support the diverse plant assemblages which make up calcareous grassland ecosystems. Chris discusses the findings from initial soil profile trials at Cranfield and their implications for calcareous grassland habitat creation.