Abstract

Liming can counteract acidification in forest soils, but the effects on soil C and N pools and fluxes over long periods are less well understood. Replicated plots in an acidic and N-rich 40-year-old Norway spruce (Picea abies) forest in SW Sweden (Hasslov) were treated with 0, 3.45 and 8.75 Mg ha(-1)of dolomitic lime (D0, D2 and D3) in 1984. Between 1984 and 2016, soil organic C to 30 cm depth increased by 28 Mg ha(-1)(30% increase) in D0 and decreased by 9 Mg ha(-1)(9.4% decrease) in D3. The change in D2 was not significant (+ 2 Mg ha(-1)). Soil N pools changed proportionally to those in soil C pools. The C and N changes occurred almost exclusively in the top organic layer. Non-burrowing earthworms responded positively to liming and stimulated heterotrophic respiration in this layer in both D2 and D3. Burrowing earthworms in D3 further accelerated C and N turnover and loss of soil. The high soil C and N loss at our relatively N-rich site differs from studies of N-poor sites showing no C and N loss. Earthworms need both high pH and N-rich food to reach high abundance and biomass. This can explain why liming of N-rich soils often results in decreasing C and N pools, whereas liming of N-poor soils with few earthworms will not show any change in soil C and N. Extractable nitrate N was always higher in D3 than in D2 and D0. After 6 years (1990), potential nitrification was much higher in D3 (197 kg N ha(-1)) than in D0 (36 kg N ha(-1)), but this difference decreased during the following years, when also the unlimed organic layers showed high nitrification potential. Our experiment finds that high-dose liming of acidic N-rich forest soils produces an initial pulse of soil heterotrophic respiration and increases in earthworm biomass, which together cause long-term declines in soil C and N pools.

Keywords

Decomposition; Heterotrophic respiration; pH; Net N mineralization; Nitrification; Nitrifiers; Earthworms

Published in

Ecosystems
2021, Volume: 24, number: 4, pages: 968-987
Publisher: SPRINGER

SLU Authors

• Persson, Tryggve

  • Department of Ecology, Swedish University of Agricultural Sciences
    

• Andersson, Stefan

  • Department of Soil and Environment, Swedish University of Agricultural Sciences
    

• Grönqvist, Tomas

  • Department of Applied Animal Science and Welfare, Swedish University of Agricultural Sciences
    

• Högbom, Lars

  • Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
    
  • Forestry Research Institute of Sweden, Skogforsk

• Vegerfors-Persson, Birgitta

  • Department of Energy and Technology, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Ecology


Publication identifier

DOI: https://doi.org/10.1007/s10021-020-00563-y

Permanent link to this page (URI)

https://res.slu.se/id/publ/108184