Introducing ……...

1. Introducing ……... Slate waste

2. EU Life-Environment funded project: Sustainable post-industrial land restoration and re-creation of high biodiversity natural habitats Partners: University of Wales, Bangor; Alfred McAlpine Slate; Slate Ecology Co., Pizarras- Villar del Rey Output: To produce a science-based guide to Best Practice for achieving the restoration of self-sustaining, semi-natural ecosystems of high conservation value

3. Scope of the project • Nutrient and water delivery systems • Plant responses • Litter decomposition and soil formation • Invertebrate, detritivore and bird biodiversity • Socio-economic impacts • GIS overlays of environmental variables

4. Soil functioning in natural and restored systems on slate waste Julie Williamson1, Davey Jones1, Richard Bardgett2, Phil Hobbs3, Ed Rowe1, Mark Nason1 & John Healey1. 1 University of Wales, Bangor, 2 University of Lancaster, 3 IGER.

5. Rationale and Hypotheses • typically, quarry sites lack topsoil • H.1 theoretical C:N considerations can be used to design substrates from organic wastes for nutrient delivery • nutrient cycling needs a ‘kick start’ • H.2 organic matter increases nutrient cycling capacity • need to develop soil biochemical indices that predict longer-term above-ground success • H.3 organic amendments create a substrate biochemically comparable to that of naturally established vegetation

6. Method used for tree planting 1-year old transplant Slates arranged to Free-draining collect rainfall coarse slate waste Soil amendments in 3 L pocket, depth 15 cm Roots moving towards fines 1m Water-holding fines

7. Design of tree establishment trial 3 water-holding treatments None Boulder clay Polyacrylamide gel 3 nutrient supply treatments None *Sewage-paper NPK (15:10:10) mix slow release * mixed to a target C:N of 15-20 and to deliver mineral N at the same rate as NPK in Year 1

8. Materials used for tree establishment Selected nutrient concentrations of the organic amendment. Target application rates to planting pocket kg.N ha-1 NPK 550 sewage-paper 4000

9. Results: substrate Mineral-N content (mg N.kg-1) over 3 samplings (1, 7, 13 months)

10. Results:soil microbial biomass (mg N.kg-1) and basal respiration (mg C.kg-1.h-1) at 13 months

11. Results: summary of soil N pool sizes at 13 months *PMN is potentially mineralisable N

13. Results: comparing soil quality indices of naturally established and planted birch.

14. Results: comparing soil quality indices of naturally established and planted birch.

15. Results: Soil microbial PLFA profiles of natural and planted vegetation. Proportion (% mol) of Gram+ve bacterial PLFA to total. S S S < Natural >< Planted >

16. Results: Soil microbial PLFA profiles of natural and planted vegetation. Ratio of fungal-to-bacterial PLFA. Ratio of fungal to bacterial PLFA < Natural >< Planted >

17. Results:Soil microbial PLFA variation in natural and planted vegetation. Plot of coordinates derived from detrended correspondence analysis (Canoco)

18. Conclusions H.1 theoretical C:N considerations can be used to design substrates from organic wastes for nutrient delivery Yes; soil mineral N concentrations during the first 13 months in the NPK treatment were matched by the sewage-paper mix treatment H.2 organic matter increases nutrient cycling capacity Yes; as evidenced by increases in microbial biomass, respiration and potentially mineralisable N, relative to other treatments

19. Conclusions cont’d • H.3 organic amendments create a substrate biochemically comparable to that of naturally established vegetation • Sewage-paper resulted in soil microbial biomass and respiration rate comparable to those in natural systems • But, microbial composition differed markedly, viz: • Planted systems had: • greater proportion of bacterial PLFA • lower microbial C:N ratio • higher respiratory quotient