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- Persson, Tryggve, et al.
(författare)
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Long-Term Impact of Liming on Soil C and N in a Fertile Spruce Forest Ecosystem
- 2021
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Ingår i: Ecosystems. - : Springer Science and Business Media LLC. - 1432-9840 .- 1435-0629. ; 24, s. 968-987
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Tidskriftsartikel (refereegranskat)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.
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| 2. |
- Taylor, Astrid, et al.
(författare)
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Ant and Earthworm Bioturbation in Cold-Temperate Ecosystems
- 2019
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Ingår i: Ecosystems. - : Springer Science and Business Media LLC. - 1432-9840 .- 1435-0629. ; 22, s. 981-994
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Tidskriftsartikel (refereegranskat)abstract
- In temperate ecosystems, earthworms and ants are the most important organisms for bioturbation. Little is known about how these groups contribute to bioturbation in different environments and to what extent overall bioturbation depends on their diversity. We developed a formula that allows quantification of annual earthworm bioturbation, thereby taking differences between earthworm ecotypes into account. With this formula, we calculated earthworm bioturbation at three sites, each with vegetation types typically found in Northern Europe. Earthworm bioturbation was low (1 Mg dry soil ha(-1) y(-1)) in Scots pine and Norway spruce forests with acidic soil (pH 3.9-4.4) and high (between 15 and 34 Mg dry soil ha(-1) y(-1)) in broadleaf forests, grasslands, alder carr and spruce forests on calcareous soil. Burrowing (endogeic and anecic) earthworms accounted for most of the earthworm bioturbation, and these worms had the highest population densities at moderate-to-high soil pH (pH 5-7.2). Estimates of ant bioturbation at the same sites were based on nest abundance, size and residence time. Mean ant bioturbation varied between 0.2 and 1 Mg dry soil ha(-1) y(-1), but individual plots had up to 2.4 Mg dry soil ha(-1) y(-1). In soils with pH higher than 5, the relative contribution of ants to total bioturbation was only 1-5%. Ant bioturbation was higher than earthworm bioturbation only in some forest soils with pH 3.9-4.4. Thus, earthworms appear to be the dominant cause of bioturbation in most types of terrestrial ecosystems in the cold-temperate areas of Europe and when information on local earthworm communities and monthly soil temperatures is available, bioturbation can be quantified using the presented 'earthworm bioturbation formula'.
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