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Nematodes enhance plant growth and nutrient uptake under C and N-rich conditions

View Article: PubMed Central - PubMed

ABSTRACT

The role of soil fauna in crucial ecosystem services such as nutrient cycling remains poorly quantified, mainly because of the overly reductionistic approach adopted in most experimental studies. Given that increasing nitrogen inputs in various ecosystems influence the structure and functioning of soil microbes and the activity of fauna, we aimed to quantify the role of the entire soil nematode community in nutrient mineralization in an experimental set-up emulating nutrient-rich field conditions and accounting for crucial interactions amongst the soil microbial communities and plants. To this end, we reconstructed a complex soil foodweb in mesocosms that comprised largely undisturbed native microflora and the entire nematode community added into defaunated soil, planted with Lolium perenne as a model plant, and amended with fresh grass-clover residues. We determined N and P availability and plant uptake, plant biomass and abundance and structure of the microbial and nematode communities during a three-month incubation. The presence of nematodes significantly increased plant biomass production (+9%), net N (+25%) and net P (+23%) availability compared to their absence, demonstrating that nematodes link below- and above-ground processes, primarily through increasing nutrient availability. The experimental set-up presented allows to realistically quantify the crucial ecosystem services provided by the soil biota.

No MeSH data available.


Mean nematode abundance of each trophic group in reinoculated samples (+Nem) on the 7th, 47th and 105th days after incubation.The −Nem treatment is not presented as this treatment was without nematodes. The error bars indicate the standard error of the mean (n = 3).
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f1: Mean nematode abundance of each trophic group in reinoculated samples (+Nem) on the 7th, 47th and 105th days after incubation.The −Nem treatment is not presented as this treatment was without nematodes. The error bars indicate the standard error of the mean (n = 3).

Mentions: The abundance and functional composition of nematodes in reinoculated samples (+Nem) was similar (18.0 vs. 18.3 ind. g−1 dry soil) to the non-irradiated fresh control samples (CTR). All the nematode taxa identified in the CTR were also identified in the reinoculated samples and showed no significant differences in abundance of each trophic group (S1). No significant differences were found for any nematode indices between the CTR and +Nem treatments at the beginning of the experiment (S2). The total abundance and the abundances of herbivores, bacterivores and fungivores significantly increased (p < 0.01) over time in reinoculated samples (Fig. 1). The bacterivores significantly increased (p < 0.05) from day 7 to day 47 and from day 47 to day 105, while fungivores and herbivores increased only from day 47 to day 105. The trophic composition was dominated by both herbivores (43%) and bacterivores (47%) at the beginning of the incubation. However, by the end of the incubation herbivores dominated (55%) over bacterivores (28%) and fungivores (15%), even though the latter two groups significantly increased in abundance over time (Fig. 1).


Nematodes enhance plant growth and nutrient uptake under C and N-rich conditions
Mean nematode abundance of each trophic group in reinoculated samples (+Nem) on the 7th, 47th and 105th days after incubation.The −Nem treatment is not presented as this treatment was without nematodes. The error bars indicate the standard error of the mean (n = 3).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5015107&req=5

f1: Mean nematode abundance of each trophic group in reinoculated samples (+Nem) on the 7th, 47th and 105th days after incubation.The −Nem treatment is not presented as this treatment was without nematodes. The error bars indicate the standard error of the mean (n = 3).
Mentions: The abundance and functional composition of nematodes in reinoculated samples (+Nem) was similar (18.0 vs. 18.3 ind. g−1 dry soil) to the non-irradiated fresh control samples (CTR). All the nematode taxa identified in the CTR were also identified in the reinoculated samples and showed no significant differences in abundance of each trophic group (S1). No significant differences were found for any nematode indices between the CTR and +Nem treatments at the beginning of the experiment (S2). The total abundance and the abundances of herbivores, bacterivores and fungivores significantly increased (p < 0.01) over time in reinoculated samples (Fig. 1). The bacterivores significantly increased (p < 0.05) from day 7 to day 47 and from day 47 to day 105, while fungivores and herbivores increased only from day 47 to day 105. The trophic composition was dominated by both herbivores (43%) and bacterivores (47%) at the beginning of the incubation. However, by the end of the incubation herbivores dominated (55%) over bacterivores (28%) and fungivores (15%), even though the latter two groups significantly increased in abundance over time (Fig. 1).

View Article: PubMed Central - PubMed

ABSTRACT

The role of soil fauna in crucial ecosystem services such as nutrient cycling remains poorly quantified, mainly because of the overly reductionistic approach adopted in most experimental studies. Given that increasing nitrogen inputs in various ecosystems influence the structure and functioning of soil microbes and the activity of fauna, we aimed to quantify the role of the entire soil nematode community in nutrient mineralization in an experimental set-up emulating nutrient-rich field conditions and accounting for crucial interactions amongst the soil microbial communities and plants. To this end, we reconstructed a complex soil foodweb in mesocosms that comprised largely undisturbed native microflora and the entire nematode community added into defaunated soil, planted with Lolium perenne as a model plant, and amended with fresh grass-clover residues. We determined N and P availability and plant uptake, plant biomass and abundance and structure of the microbial and nematode communities during a three-month incubation. The presence of nematodes significantly increased plant biomass production (+9%), net N (+25%) and net P (+23%) availability compared to their absence, demonstrating that nematodes link below- and above-ground processes, primarily through increasing nutrient availability. The experimental set-up presented allows to realistically quantify the crucial ecosystem services provided by the soil biota.

No MeSH data available.