Effects of hardened wood ash on microbial activity, plant growth and nutrient uptake by ectomycorrhizal spruce seedlings

Authors

  • Shahid Mahmood,

    1. Department of Microbial Ecology, University of Lund, Ecology Building, S-223 62 Lund, Sweden
    Search for more papers by this author
    • 1

      Department of Molecular and Cell Biology, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK.

  • Roger D. Finlay,

    1. Department of Forest Mycology and Pathology, Swedish University of Agricultural Sciences, Box 7026, S-750 07 Uppsala, Sweden
    Search for more papers by this author
  • Ann-Mari Fransson,

    1. Department of Plant Ecology, University of Lund, Ecology Building, S-223 62 Lund, Sweden
    Search for more papers by this author
  • Håkan Wallander

    Corresponding author
    1. Department of Microbial Ecology, University of Lund, Ecology Building, S-223 62 Lund, Sweden
    Search for more papers by this author

*Corresponding author. Tel.: +46 (46) 222 3759; Fax: +46 (46) 222 4158. hakan.wallander@mbioekol.lu.se

Abstract

Plant growth, nutrient uptake, microbial biomass and activity were studied in pot systems containing spruce seedlings colonised with different ectomycorrhizal fungi from an ash-fertilised forest. The seedling root systems were enclosed in mesh bags inside an outer compartment containing crushed, hardened wood ash. Three different species of mycorrhizal fungi and a non-mycorrhizal control were exposed to factorial combinations of ash and N addition. Ash treatment had a highly significant, positive effect on plant growth and on shoot and root concentrations of K, Ca and P, irrespective of mycorrhizal status. Mycorrhizal inoculation had a significant effect on plant growth, which was proportionally greater in the absence of ash. N addition had a significant positive effect on plant biomass in mycorrhizal treatments with ash, but no effect in non-mycorrhizal treatments or most of the mycorrhizal treatments without ash. Piloderma sp. 1, which was earlier found to colonise wood ash granules in field studies, appeared to accumulate Ca from ash in the mycorrhizal roots. 5–6.7% of the total P in the ash was solubilised, with 0.9–1.5% in solution, 3.6–4.6% in the plants and 0.5–1.5% in microbial biomass. Bacterial activity as determined by [3H]-thymidine and [14C]-leucine incorporation was significantly greater in ash treatments than in controls with no ash addition. Principal component analysis (PCA) of phospholipid fatty acids (PLFAs) showed a clear difference in bacterial community structure between samples collected from ash-treated pots and controls without ash.

Ancillary