Phosphorus regulates ectomycorrhizal fungi biomass production in a Norway spruce forest
<p>Ectomycorrhizal fungi (EMF) are important components of soil microbial communities, and EMF biomass can potentially increase carbon (<span class="inline-formula">C</span>) stocks by accumulating in the soils as necromass and producing recalcitrant structures. EMF grow...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2023-04-01
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| Series: | Biogeosciences |
| Online Access: | https://bg.copernicus.org/articles/20/1443/2023/bg-20-1443-2023.pdf |
| Summary: | <p>Ectomycorrhizal fungi (EMF) are important components of soil microbial communities, and EMF biomass can potentially increase carbon (<span class="inline-formula">C</span>)
stocks by accumulating in the soils as necromass and producing recalcitrant structures. EMF growth depends on the <span class="inline-formula">C</span> allocated belowground by
the host trees, and the nutrient limitation on tree growth is expected to influence this allocation. Therefore, studying EMF production and
understanding the factors that regulates it in natural soils are important to understand <span class="inline-formula">C</span> cycling in forests.</p>
<p>Fungal mycelium collected from ingrowth mesh bags is commonly used to estimate EMF biomass, but these measurements might not reflect the total
EMF production since turnover rates of the hyphae are not considered. Here we estimated EMF production and turnover in response to
<span class="inline-formula">P</span> fertilization (applied as superphosphate) in a Norway spruce forest where nitrogen (<span class="inline-formula">N</span>) deposition has resulted in
phosphorus (<span class="inline-formula">P</span>) limitation of plant production by using a combination of mesh bags with different incubation periods and with Bayesian
inferences. To test how localized patches of <span class="inline-formula">N</span> and <span class="inline-formula">P</span> influence EMF production and turnover we amended some bags with a nitrogen source
(methylene urea) or <span class="inline-formula">P</span> source (apatite). Additionally, the Bayesian model tested the effect of seasonality (time of mesh-bag harvesting) on
EMF production and turnover.</p>
<p>We found that turnover of EMF was not affected by <span class="inline-formula">P</span> fertilization or mesh-bag amendment. <span class="inline-formula">P</span> fertilization had a negative effect on
EMF production in all the mesh-bag amendments, suggesting a reduced belowground <span class="inline-formula">C</span> allocation to the EMF when <span class="inline-formula">P</span> limitation is
alleviated. Apatite amendment significantly increased EMF biomass production in comparison with the pure quartz bags in the control plots but not in
the <span class="inline-formula">P</span>-fertilized plots. This indicates that <span class="inline-formula">P</span>-rich patches enhance EMF production in <span class="inline-formula">P</span>-limited forests, but not when <span class="inline-formula">P</span>
is not limiting. Urea amendment had a generally positive effect on EMF production, but this was significantly reduced by <span class="inline-formula">P</span> fertilization,
suggesting that a decrease in EMF production due to the alleviated <span class="inline-formula">P</span> limitation will affect <span class="inline-formula">N</span> foraging. Seasonality had a significant
effect on EMF production, and the differences registered between the treatments were higher during the warmer months and disappeared at the end of
the growing season.</p>
<p>Many studies highlight the importance of <span class="inline-formula">N</span> for regulating belowground <span class="inline-formula">C</span> allocation to EMF in northern coniferous forests, but here we
show that the <span class="inline-formula">P</span> status of the forest can be equally important for belowground carbon allocation to EMF production in areas with high
<span class="inline-formula">N</span> deposition.</p> |
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| ISSN: | 1726-4170 1726-4189 |