SSS4.4

EDI
Soil Biodiversity across scale in a changing world

Soil organisms comprise a large fraction of global terrestrial diversity and are responsible for essential ecosystem functions and services, such as determining plant productivity, nutrient cycling, organic matter decomposition, pollutant degradation and pathogen control. However, soil biodiversity and its functional roles are determined by the abiotic surrounding. As such, anthropogenic influences including urbanization, land-use change, pollution, invasions etc., alter soil biodiversity and its functions. Here we aim to showcase recent advances on how anthropogenic drivers determine soil biodiversity and how that subsequently feeds-back to ecosystem functions and human health.
This session invites contributions that showcase examples of: 1) Mapping soil biodiversity under different anthropogenic influences; 2) Understanding the functional implication of anthropogenic changes of soil biodiversity; 3) Protecting and restoring biodiversity in anthropogenically altered soils; 4) Manipulating soil biodiversity to increase ecosystem functions and human health under anthropogenic factors.

Convener: Xin SunECSECS | Co-conveners: Mohammad Bahram, Anton PotapovECSECS, Michael SteinwandterECSECS, Qi Li, Manqiang Liu, Bettina Weber, Yong-Guan Zhu, Stefan Geisen
Presentations
| Mon, 23 May, 10:20–11:48 (CEST), 13:20–14:38 (CEST)
 
Room 0.49/50

Presentations: Mon, 23 May | Room 0.49/50

Chairperson: Bettina Weber
10:20–10:30
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EGU22-8252
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solicited
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Presentation form not yet defined
fiona fraser, Ronald Corstanje, Lindsay Todman, Diana Bello-Curás, Gary Bending, Lynda Deeks, Jim Harris, Sally Hilton, Mark Pawlett, Joanna Zawadzka, Andrew Whitmore, and Karl Ritz

The resilience of ecological systems is crucially important, particularly in the context of climate change. We present experimental evidence of critical slowing-down arising from perturbation of a key function in a complex ecosystem, exemplified by soil. Different behavioural classes in soil respiratory patterns were detected in response to repeated drying:rewetting cycles. We characterised these as adaptive, resilient, fragile or non-resilient. The latter involved increasing erratic behaviour (i.e. increasing variance), and the propagation of such behaviour (i.e. autocorrelation), interpreted as a critical slowing-down of the observed function. Soil microbial phenotype and land-use were predominantly related to variance and autocorrelation respectively. No relationship was found between biodiversity and resilience, but the ability of a community to be compositionally flexible rather than biodiversity per se appeared to be key to retaining system function. These data were used to map the extent to which soils are close to crossing into alternative stable states at a national scale.

How to cite: fraser, F., Corstanje, R., Todman, L., Bello-Curás, D., Bending, G., Deeks, L., Harris, J., Hilton, S., Pawlett, M., Zawadzka, J., Whitmore, A., and Ritz, K.: Evidence of ecological critical slowing-down in temperate soils, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8252, https://doi.org/10.5194/egusphere-egu22-8252, 2022.

10:30–10:36
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EGU22-1400
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Presentation form not yet defined
Bin Ma, Yiling Wang, and Jianming Xu

Soil microbes play a crucial role in terrestrial ecosystem biogeochemical cycling1 and understanding microbial biogeography has provided fundamental information to predict ecosystem function2. In contrast, the biogeography of soil viromes has been largely overlooked, even though viruses are key mediators of the soil microbiome and its function3. Here, we introduce the Global Soil Virome (GSV) dataset, the most comprehensive soil virus dataset to date, and present an overview of global biogeographic patterns and drivers of soil viromes. A total of 345,607 double stranded DNA partial viral genomes, of which 97.2% were unknown viral taxa, were assembled from 1,873 deeply sequenced soil metagenomes across the globe. We observed soil virome endemism across continents and plant biomes which were shaped by dispersal limitation and soil moisture. Unlike the scale-free pattern of most biological co-occurrence networks4,5, we found that the degree distribution of the global soil virus co-occurrence network has a random pattern. The GSV dataset provides a critical resource for elucidating soil viral diversity and host-virus interactions; it provides in-depth insight into ecological processes that determine soil viral diversity.

How to cite: Ma, B., Wang, Y., and Xu, J.: Biogeographic patterns and drivers of soil virosphere across the globe, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1400, https://doi.org/10.5194/egusphere-egu22-1400, 2022.

10:36–10:42
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EGU22-2267
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ECS
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Virtual presentation
Anton Potapov and the Soil BON Foodweb Team

Soils host approximately 50% of the biomass and a major part of the diversity of animals on land. However, large-scale data that link soil animal diversity with ecosystem functions is limited to few regional studies, hampering our understanding of soil animal contribution to global biogeochemistry. Besides, global abiotic and biotic drivers and assembly processes in soil animal communities and food webs have not been comprehensively assessed. Here we introduce Soil BON Foodweb Team (SBF Team), a novel international voluntary initiative that addresses these gaps by a standardized global assessment of soil animal communities across micro-, meso-, and macrofauna. By sampling Soil BON sites (https://www.globalsoilbiodiversity.org/soilbon), this initiative is the first to link soil animal communities across the size spectrum to a range of soil functions worldwide. At present the initiative includes soil ecologists from 15+ countries covering all continents. We intend to expand the network and conduct the first sampling campaign in 2022 covering a minimum of 200 sampling sites globally. We are welcome for researchers especially from underrepresented countries. Jointly, we will be able to produce unprecedented data to address exciting and challenging questions and establish a global collaboration network for soil animal diversity monitoring and future joint work.

How to cite: Potapov, A. and the Soil BON Foodweb Team: Global monitoring of soil animal communities using a common methodology, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2267, https://doi.org/10.5194/egusphere-egu22-2267, 2022.

10:42–10:48
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EGU22-8992
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ECS
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Virtual presentation
Dingyi Wang, Xianping Li, Yan Du, Jing Sun, Xiaoxu Qi, Maogang Xu, Kuihu Jiao, Yu Zhang, Chongzhe Zhang, Sibo Shi, Xin Gong, Di Wu, and Manqiang Liu

Global biodiversity is being threatened by climate change and human activities. Prior studies have demonstrated the negative concequences of land-use such as conversion of forest into monoculture, while its effects on belowground organisms especially soil invertebrates remain unclear. Earthworms are well-known ecosystem engineers that deliver multiple ecosystem functions including decomposition, carbon sequestration and plant growth. Yet, all of those functions are negatively affected by land-use conversion. Previous studies concerning land-use effects on soil biodiversity were generally conducted at a single site and small spatial scale, how soil biodiversity changes across spatial scales remains poorly understood.

In current study, earthworms were quantitatively sampled from 41 sites in three land-use types (i.e., farmland, orchard and forest at each site, five replicates) in subtropical region of China. Earthworm species were identified using both morphological and molecular methods. Earthworm density, biomass and body size were recorded. Notably, the species were also classified into different functional guilds. Totally, 84 species (or subspecies) were identified. Generally, local diversity (α diversity) was higher in agricultural lands than in forest lands, however, the opposite was true for regional diversity (γ diversity). In addition, the density of earthworm was the lowest in forest, while the biomass and body size were higher in agricultural lands. A higher proportion of endogeic and anecic earthworms were found in farmland and orchard than in forest. The land-use caused changes in soil properties contributed to the difference in earthworm diversity, abundance, biomass and body size.

In conclusion, we suggest that the impacts of human land-use on soil earthworm assemblage are scale-dependent, and the diversity, abundance, biomass and body size respond differently to land-use. Researches on different scales about land-use effects to soil biodiversity are urgently needed.

How to cite: Wang, D., Li, X., Du, Y., Sun, J., Qi, X., Xu, M., Jiao, K., Zhang, Y., Zhang, C., Shi, S., Gong, X., Wu, D., and Liu, M.: Human land-use increases earthworm diversity at local scale but not at the regional scale while improves abundance, biomass, and body size, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8992, https://doi.org/10.5194/egusphere-egu22-8992, 2022.

10:48–10:54
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EGU22-1020
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Virtual presentation
Maria Nour El Houda Bensayah, Mokhtar Karabi, Baelhadj Hamdi Aissa, and Ismaiel Berkal

The objective of this work is to study the effect of microorganisms on carbon sequestration in
different soil landscapes of Ouargla’s basin. Ouargla is part of the arid zones of the Algerian
Sahara, which is characterized by high temperatures, low and irregular precipitation, sparse
vegetation and soils poor in organic matter. However, the soil remains a favorable environment
for macros and microorganisms which tolerates this deficit. The soil provides ecosystem services
to these environments by protecting natural resources. Microbial biomass, which represents on
average 2 to 4% of organic carbon, is involved in renewing organic matter in the soil. For this
study, 7 stations of different pedo- sequences were chosen. After collection, the samples
underwent microbiological analyzes for enumeration of bacteria and fungi, fumigation-extraction
and physicochemical analyzes. The enumeration of the main microbial groups in bacteria and
fungi showed the predominance of bacterial microflora, followed by fungal microflora at higher
values in cultivated soil and those of Sebkhat. The identification of fungal species according to the
determination keys allowed us to identify the following species: Alternaria alternata, Rizopus sp
and Aspergillus niger, as well as yeasts. The microbial carbon values show that this parameter is
higher in Sebkhat N’Goussa, gypsum soil in Frane and in cultivated soil. These are the stations
where high values of organic carbon and organic matter are recorded. We can say that
microorganisms play an important role in carbon sequestration. They mineralize microbial
residues and provide carbon to the stable organic matter fraction of the soil. 

 


Key words: carbon sequestration, ecosystem service, microbial carbon, organic carbon, Ouargla.

How to cite: Bensayah, M. N. E. H., Karabi, M., Hamdi Aissa, B., and Berkal, I.: Effect of soil microorganisms on organic carbon sequestrationindifferent soil landscapes of the Ouargla’s basin, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1020, https://doi.org/10.5194/egusphere-egu22-1020, 2022.

10:54–11:00
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EGU22-6520
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ECS
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Virtual presentation
Mikhail Semenov, George Krasnov, Natalia Ksenofontova, and Dmitry Nikitin

Microbial taxonomic diversity is considered as one of the crucial factors responsible for the sustainable functioning of soil systems. However, it is still unclear to what extent microbial taxonomic diversity reflects its functional diversity. In this study, we compared taxonomic and functional diversity of the soil microbiome in a few natural and agricultural ecosystems.
Soil samples were collected three times (April, July, and October) from grassland, deciduous forest, and three agricultural ecosystems (no fertilizers, NPK, cattle manure). We applied high-throughput sequencing on the Illumina MiSeq platform using a combination of multiple DNA metabarcoding markers and characterized soil prokaryotic (16S rRNA gene: bacteria and archaea) and eukaryotic (ITS2 to target fungi; 18S rRNA gene to target protists) communities. Community-level physiological profiles of the soil microbiomes were analyzed using Biolog Ecoplates to assess functional diversity of heterotrophic microorganisms.
All five soils differed significantly from each other in the taxonomic composition of the bacteriome, the mycobiome, and the protistome. The forest soil microbiome was characterized by the higher relative abundances of Verrucomicrobia, Agaricomycetes, Apicomplexa, and Mesomycetozoa. Proteobacteria, Acidobacteria, Sordariomyces, Cercozoa, and Ochrophyta were the dominant taxa in the agricultural soils. Surprisingly, taxonomic diversity of the bacteriome, the mycobiome, and the protistome in forest soil was significantly lower compared to the agricultural soils (except the NPK treatment). Differences in microbial physiological profiles between distinct ecosystems were much lower than those in taxonomic diversity. The forest soil microbiome was characterized by the highest physiological activity and plasticity, especially for amines and phenolic compounds. Our findings suggest that lower microbial taxonomic diversity does not necessarily result in lower functional diversity of the soil microbiome.

This research was supported by the Russian Science Foundation, Project No 21-76-10025.

How to cite: Semenov, M., Krasnov, G., Ksenofontova, N., and Nikitin, D.: Higher taxonomic diversity of protists, fungi and bacteria, but lower functional diversity in soils of agricultural ecosystems compared to a deciduous forest, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6520, https://doi.org/10.5194/egusphere-egu22-6520, 2022.

11:00–11:06
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EGU22-2153
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Virtual presentation
Zhengkun Hu, Xiaoyun Chen, Feng Hu, and Manqiang Liu

Anthropogenic activities have profoundly increased the nutrient inputs into soil through inorganic nitrogen (N) and phosphorus (P) fertilization and atmospheric deposition over recent decades. In grasslands, nutrient enrichment is one of the most important global change factors affecting a range of ecosystem functions and services. Nutrient enrichment promotes some functions such as plant production, but at the cost of other ecosystem functions, which may obscure the net effects on multiple ecosystem functions (i.e., ecosystem multifunctionality). In particular, nutrient enrichment can strongly reduce above- and below-ground biodiversity, which might threaten ecosystem services that delivered by biodiversity. However, our understanding of the importance of soil biota as a component of nutrient-enrichment effects on ecosystem multifunctionality is still limited.

Taking advantages of a long-term field study and a controlled microcosm experiment, we explored whether and how nutrient enrichment affects ecosystem multifunctionality in a Tibetan alpine meadow. The diversity of soil biota across multiple trophic, including bacteria, fungi, protists and nematodes for two consecutive years were investigated from a 13-year field experiment under a gradient of N and P enrichment. A total of 14 ecosystem functions that are influenced by soil biota were measured and were grouped into five categories: (1) nutrient cycling, (2) SOM decomposition, (3) carbon and nutrient cycling drivers, (4) soil structure, and (5) pest control. To generate a comprehensive understanding of the biodiversity-ecosystem-function relationship under nutrient enrichment, a microcosm inoculation experiment using the dilution-to-extinction approach was conducted with soil samples with or without nutrient enrichment.

Our results showed that nutrient enrichment weakened multifunctionality by reducing the multidiversity across soil food webs. Specially, soil biodiversity at higher trophic levels (e.g., microbivorous nematode) supported a greater number of ecosystem functions at high levels of functioning than those of lower trophic levels, such as bacteria and fungi. Microcosm experiment further demonstrated that nutrient enrichment weakened the relationships between soil biodiversity and ecosystem multifunctionality. Together, our results provide insight into the importance of soil biodiversity for maintaining soil multifunctionality under nutrient enrichment, as well as providing strong support for inclusion of multiple aspects of soil biodiversity in conservation and management policies under global change scenarios.

How to cite: Hu, Z., Chen, X., Hu, F., and Liu, M.: Nutrient enrichment reduces soil multidiversity and multifunctionality in an alpine meadow, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2153, https://doi.org/10.5194/egusphere-egu22-2153, 2022.

11:06–11:12
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EGU22-2756
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On-site presentation
Maria Korneykova, Dmitriy Nikitin, Viacheslav Vasenev, and Andrey Dolgikh

Soil microbial properties are highly sensitive to anthropogenic disturbance and a considerable impact of urbanization on soil microbial activity and diversity was reported for various cities and climates. The quantitative parameters of the soils’ microbiome in Arctic cities including the structure of microbial biomass and the number of ribosomal genes remain overlooked. This research aimed to compare quantitative indicators, as well as the functional diversity of soil microbial communities in the Arctic cities of Murmansk and Apatity located on the Kola Peninsula.

Murmansk (68.967 N, 33.083 E) is the biggest Arctic city in the world, located in the natural zone of the forest-tundra. Apatity (67.5°N, 33.4°E) is the fifth largest city in polar zone, located in the northern taiga zone.

Samples were collected from the topsoil horizons according to the standard sampling procedure with possible measures to prevent contamination. Quantitative assessment of the content of ribosomal genes of bacteria, archaea, and fungi was performed by real-time polymerase chain reaction (PCR). The prokaryotes and fungal biomass were determined by luminescence microscopy method. Community level physiological profiling (CLPP) was based on MicroRespТМ approach using substrates representing C sources of different quality: amino acids, carbohydrates, carboxylic and phenolic acid.

The number of archaea was an order of magnitude higher in Murmansk (predominantly 1010 of 16s rRNA genes/g soil) than in Apatity (predominantly 109 of 16s rRNA genes/g soil); the number of 16s rRNA genes copies of bacteria was an order of magnitude lower in Murmansk (109-1010) compared to Apatity; the number of copies of the ITS rRNA genes of fungi was the same for both locations - 109 on average.

The biomass of prokaryotes was 5 times higher in Murmansk (5-25 μg/g soil) compared to Apatity (1-6 μg/g soil); the fungal biomass was 3.3 times higher in Murmansk (50-1000 μg/g soil) than in Apatity (40-300 μg/g soil). The length of the mycelium of actinomycetes in the soils of Murmansk (1-100 m/g of soil) was an order of magnitude higher than that in Apatity (0-10 m/g of soil); the length of the fungal mycelium was 3.5 times longer in Murmansk (10-600 m/g of soil) than in Apatity (0-170 m/g of soil).

Soil microbial communities in Arctic cities had a similar physiological profile. Groups of microorganisms consuming carbohydrates and carboxylic acids prevailed. The soils of both cities contained microorganisms capable of decomposing complex organic compounds with a benzene ring, such as phenolic acids (vanillic and lilac), which indicates the potential for the destruction of difficult-to-decompose  substances.

Thus, soil microbial communities in Arctic cities differ to a greater extent in quantitative parameters than in qualitative ones (on example of functional diversity). Probably, the quantitative parameters are more influenced by microclimatic conditions, type of vegetation, level of anthropogenic load, etc.

Acknowledgements This research was supported by RFBR #19-29-05187 and RUDN University Strategic Academic Leadership Program.

How to cite: Korneykova, M., Nikitin, D., Vasenev, V., and Dolgikh, A.: Quantitative indicators and functional diversity of soil microbial communities in the Russian Arctic cities , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2756, https://doi.org/10.5194/egusphere-egu22-2756, 2022.

11:12–11:18
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EGU22-3548
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ECS
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Virtual presentation
Yu Hui Li, Xu Han, Ying bin Li, Qi Li, and Martijn Bezemer

The improvement and protection of ecosystem function are important in the restoration of grassland ecosystem, especially in degraded grasslands. Soil inoculation provides an effective way for the restoration of degraded ecosystems. Here we conducted a field soil inoculation experiment and selected two well-developed soils (meadow steppe and upland meadow) to transplant them into degraded grasslands at three inoculation amounts (0.01 m3, 0.03 m3 and 0.05 m3 per square meter). After three years of soil inoculation, we assessed the ecosystem multifunctionality (including plant productivity, and functions related to nutrient cycling) of different treatments with different identity and amount of soil inoculation. Principal co-ordinates analysis suggested that different identity of soil inoculum resulted in different development of soil fungal and bacterial communities. Ecosystem multifunctionality was significantly improved with the increase of soil inoculation amounts. Spearman’s correlation analysis showed a positive association between ecosystem multifunctionality and soil fungal richness, plant cover, and the amount of soil inoculation. Our results indicate that soil inoculation can enhance ecosystem multifunctionality by affecting the soil biotic and plant communities. Our finding has important implications for better restoration of biodiversity and ecosystem functioning in degraded grassland ecosystems.

How to cite: Li, Y. H., Han, X., Li, Y. B., Li, Q., and Bezemer, M.: Soil inoculation improves ecosystem function in degraded grasslands, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3548, https://doi.org/10.5194/egusphere-egu22-3548, 2022.

11:18–11:24
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EGU22-419
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ECS
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On-site presentation
Camille D'Hervilly, Isabelle Bertrand, Laurent Berlioz, Lydie Dufour, and Claire Marsden

In alley cropping sites, parallel tree rows covered with herbaceous vegetation are added into cropped fields. These tree rows provide an additional habitat for many soil organisms in plots that are usually low in biodiversity. Previous studies showed that tree rows present a higher diversity and higher densities of soil fauna compared to the crop alleys. However, it is not sure that the crop alleys really benefit from the presence of additional fauna in the tree rows. A possible benefit could come from a dispersal of soil fauna hosted in the tree rows towards the crop alleys during favorable periods of time, but such movements have never been investigated. Our experiment investigated the movement of earthworms in tree rows vicinity in a Mediterranean alley cropping field planted with walnut trees, in which crop alleys were ploughed and cultivated with pea. Traps, consisting of three joined plastic walls sunk vertically into the soil and delimiting a cubic 25*25 cm wide soil block of 15 cm depth were placed at 30 cm from the tree row border in March 2019. These traps were opened on one side, allowing soil fauna entrance either from the tree row or from the crop alley, and defaunated at trap implementation (5 replications). Traps were removed 2 months after the beginning of the experiment and earthworm density determined by manual sorting. In addition, the plot was sampled at different distances from the tree row (0 m, 0.3 m, 1 m and 6 m i.e. in the middle of the crop alley) for earthworm density determination in 25*25*30 cm soil blocks at trap implementation and removal. Results showed that the distribution of epigeic earthworms (living at the soil surface) vary with the distance from the tree row, with more individuals found in the tree row and in its immediate vicinity than in the middle of the crop alley, while endogeic earthworms (living in the soil) presented no significant variation in their distribution with the distance from the tree row. Traps were mostly recolonized by endogeic earthworms, and significantly more earthworms were found in traps opened towards the crop alley than in traps opened towards the tree row. These results suggest than Spring was not a favorable season for earthworm dispersal from the tree row in this site, and that earthworms more probably used the tree row and its vicinity as a refuge against adverse conditions in the crop alley. This type of experiment should be repeated at other seasons, and with varying management practices of the crop alley, as different conditions could induce different movements.

How to cite: D'Hervilly, C., Bertrand, I., Berlioz, L., Dufour, L., and Marsden, C.: Unexpected movements of earthworms between tree rows and crop alleys in a Mediterranean agroforestry site, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-419, https://doi.org/10.5194/egusphere-egu22-419, 2022.

11:24–11:30
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EGU22-1632
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ECS
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Virtual presentation
Ecological and evolutionary processes shape belowground springtail communities along an elevational gradient
(withdrawn)
Xin Sun, Zhijing Xie, Donghui Wu, Ting-Wen Chen, Mikhail Potapov, and Stefan Scheu
11:30–11:36
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EGU22-3795
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Virtual presentation
Evgeny Abakumov, Timur Nizamutdinov, and Eugenia Morgun

The microbiological and agrochemical parameters of the soils of fallow (abandoned), active agroecosystems and background (benchmark) landscapes of the Yamalo-Nenets Autonomous Region were studied. The soils of vegetable gardens (the setllements of Muzhi, Nadym, Tovopogol, Polyarny, Seyakha), the soils of parks, recreational and industrial zones and archaeological monuments (the cities of Nadym, Labytnangi, Salekhard, Novy Urengoy) were studied. The morphological and taxonomic diversity of natural and agro-soils of the key plots of the study has been established. The key chemical and soil-hydrophical differences of agrozems and agro-soils from natural background soils are revealed. The parameters of the alpha and beta diversity of the soil microbial community were studied by new generation sequencing methods. The phylums of microorganisms common to all the studied soils and those phylums that are characteristic of agrogenic soils are revealed. In some cases, there is an increase in the parameters of biodiversity in agrogenic soils in comparison with to natural ones, which indicates the diversification of edaphic ecological niches. The parameters of the metabolic dynamics of the microbial community under the conditions of chemical contamination of cryogenic soils are established. Ecotoxicological studies of soils of urbanized ecosystems of a number of settlements of the Yamalo-Nenets Autonomous Regions were carried out, even in terms of assessing ecosystem services of soils. A structure has been created and a database has been partially filled, including information on the localization, diversity, current state and use of agrogenic soils in the region.

This work was supported by Russian Foundation for Basic Research, project No 19-416-890002

How to cite: Abakumov, E., Nizamutdinov, T., and Morgun, E.: Microbiological and agrochemical characteristics of abandoned agricultural soils of central part of Yamal region, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3795, https://doi.org/10.5194/egusphere-egu22-3795, 2022.

11:36–11:42
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EGU22-3485
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ECS
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Virtual presentation
Jingjing Yang, Donghui Wu, and Deli Wang

    Grassland ecosystems worldwide are facing habitat degraded due to human activities. Although it is commonly proposed that livestock can have negative repercussions for multiple ecosystem functions in degraded grasslands, this question has yet to receive explicit scientific attention. We used a 3-year field-manipulated grazing experiment, including livestock grazing by sheep across three grasslands with different levels of degradation to evaluate the role of large herbivore in regulating soil nematodes and ecosystem multifunctionality. Our findings reveal the context dependency of this role in grassland degradation. We show that livestock show higher levels of soil nematode biomass and ecosystem multifunctionality than lightly degraded grassland with enclosure, and facilitate soil nematode diversity and maintain ecosystem multifunctionality in moderately and severely degraded grasslands. We propose that moderate herbivore grazing should be considered as nature-based solutions to improve and maintain both soil nematodes and ecosystem multifunctionality in degraded grasslands. The information is fundamental for improving nature’s benefits to people and considering conservation efforts of grassland restoration.

How to cite: Yang, J., Wu, D., and Wang, D.: Proper grazing is nature-based solutions to restore soil nematodes and ecosystem multifunctionality in degraded grasslands, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3485, https://doi.org/10.5194/egusphere-egu22-3485, 2022.

11:42–11:48
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EGU22-8672
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Virtual presentation
Valentyna Krashevska and the co-authors

Testate amoebae are a common group of shelled amoeboid protists that are widespread in terrestrial systems. They play a key role in microbial foodwebs and are useful bioindicators of present and past conditions due to their long-lasting shells. However, their diversity and distribution has not yet been investigated and visualised at a global scale. With extensive data collection effort involving the global testate amoebae community, we compiled data on testate amoebae from 10,889 locations worldwide: 9235 terrestrial, 1322 freshwater and 219 marine-interstitial sites. In terrestrial systems, 1187 species were recorded. The highest total number of species was documented on the continent of Asia (699 species) and the lowers in Antarctica (151 species). Preliminary analyses of terrestrial samples showed negative correlation of species number with increasing absolute latitude, peaking at low-mid latitudes. However, longitude also played a significant role in species distribution. The most studied continent is Europe (42 % of all samples) and the least studied is Africa (2 %). The data we have collected are the basis for identifying the fundamental ecological determinants of diversity and species composition of testate amoebae and for understanding patterns in microbial diversity. We will show the recent findings of this ongoing endeavour.

How to cite: Krashevska, V. and the co-authors: Global patterns in testate amoebae diversity, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8672, https://doi.org/10.5194/egusphere-egu22-8672, 2022.

Lunch break
Chairperson: Bettina Weber
13:20–13:26
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EGU22-6933
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Virtual presentation
Jérôme Cortet, Maria Tsiafouli, Paul-Henning Krogh, and David Russel

The protection of soil biodiversity is essential for ensuring soil functioning and provisioning of related ecosystem services, but also the conservation of species per se. For this purpose, it is essential to know what soil organism is where and how it is influenced by environmental, climate and human activities. 

Numerous studies (there are over 1400 published articles) have been elaborated in Europe regarding soil fauna. A data platform to store data on soil fauna already exists and is currently under further development to become a pan-European data warehouse for soil biodiversity (https://www.eudaphobase.eu/). Though, the data stored in this database until now comprises only a small percent of the available data. Hence, it is evident that a compiled dataset providing an overall understanding of the distribution of several taxa across European biomes and under different land use still is missing.

Attempting to fill this gap, we start a new initiative within the framework of the Cost Action EUdaphobase CA18237: the creation of the first European Atlas of Soil Fauna.  We aim to map, summarize and upscale the current knowledge on soil fauna to help in providing support to the scientific community and directions to stakeholders and policymakers. We seek collaboration (data holders and experts) to identify, collect and analyze data of all groups of micro-, meso- and macrofauna in Europe. 

This presentation will focus on the aims of this initiative and the way we plan to collect data and involve people.

How to cite: Cortet, J., Tsiafouli, M., Krogh, P.-H., and Russel, D.: Towards creating the first European Atlas of Soil Fauna, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6933, https://doi.org/10.5194/egusphere-egu22-6933, 2022.

13:26–13:32
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EGU22-3923
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Virtual presentation
Anton Potapov

Belowground consumers create complex food webs that regulate functioning, ensure stability and support biodiversity both below and above ground. However, existing soil food-web reconstructions do not match recently accumulated empirical evidence and there is no comprehensive reproducible approach that accounts for the complex resource, size and spatial structure of food webs in soil. I build on generic food-web organization principles and use multifunctional classification of soil protists, invertebrates and vertebrates, to reconstruct “multichannel” food-web across size classes of soil-associated consumers. I then use food-web reconstruction, together with assimilation efficiencies, to calculate energy fluxes assuming a steady-state energetic system. Based on energy fluxes, I describe a number of indicators, related to stability, biodiversity and multiple ecosystem-level functions such as herbivory, top-down control, translocation and transformation of organic matter. The multichannel reconstruction can be used to assess trophic multifunctionality (analogous to ecosystem multifunctionality), i.e. simultaneous support of multiple trophic functions by the food-web, and compare it across communities and ecosystems spanning beyond the soil. With further validation and parametrization, the multichannel reconstruction approach provides an effective tool for understanding and analysing soil food webs. I believe that having this tool will inspire more people to comprehensively describe soil communities and belowground-aboveground interactions. Such studies will provide informative indicators for including consumers as active agents in biogeochemical models, not only locally but also on regional and global scales.

How to cite: Potapov, A.: Multifunctionality of belowground food webs, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3923, https://doi.org/10.5194/egusphere-egu22-3923, 2022.

13:32–13:38
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EGU22-9338
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Presentation form not yet defined
Xiaoyun Chen, Mingyu Li, Lujie Qiu, Qian Yang, Yan Zhou, Baijing Zhu, Bingbing Wan, Ting Liu, Zhengkun Hu, and Manqiang Liu

Soil biota, across multitrophic levels, regulates nutrient cycling and plant performance, and thereby play an important role in delivering multiple ecosystem functions. Soil nematodes occupy diverse positions in the soil food web, such as herbivores, bacterivores, fungivores, omnivores, and predators. Therefore, soil nematodes are usually considered as potential bio-indicators of soil quality or soil health under agricultural managements. However, there is a knowledge gap on how nematode multitrophic biodiversity (here the numbers of nematode trophic groups) affects soil multifunctionality.

This study combined field and laboratory experimental approaches to quantify and disentangle the aforementioned issue. First, we explored the impacts of compost application on nematode assemblages as well as multifunctionality based on a long-term field experiment. Results showed that compost application stimulated multitrophic biodiversity by the increase of microbivore and omnivore-predator abundance, while decreasing the herbivores. Besides, the increase of nematode multitrophic biodiversity was accompanied with the soil multifuctionality. Then a complete factorial design microcosm experiment was conducted with manipulating nematode trophic levels (microbivores, herbivores and omnivore-carnivores) to test the hypothesis that increasing multitrophic biodiversity will lead to higher soil multifuctionality as indicated by plant growth and defense to the pests. Consistent with the hypothesis, we found that integrating different trophic levels, i.e. maximum multitrophic biodiversity, could promote plant growth and notably the resistance to pest infestation through changing plant chemical composition. Particularly, we found microbivores reduced root biomass while omnivore-carnivores increased plant shoot biomass. The presence of omnivore-carnivores could suppress the abundance of insect (brown planthoppers) by regulating soil microbiome. In summary, the increment of soil multitrophic biodiversity have multifunctional consequence.

Overall, we provide direct experimental evidence for the multifunctional roles of soil multitrophic biodiversity. Further, soil organic management practices, regardless of organic amendments, non-tillage or growing cover crops, that improving soil habitat like resource and structure, and consequently promoting soil biodiversity especially higher-level biotic associations or trophic interactions may ultimately contribute to sustaining multiple ecosystem services including both crop productivity and pathogen controls. Such knowledge helps advance the mechanical understanding of biotic drivers of soil ecosystem functioning. It also highlights that organic management could strengthen the carbon-based ecosystem services if considering the extra benefits provided by soil biodiversity. Overall, our study corroborated organic management will be crucial to implement an ecologically multifunctional agriculture.

How to cite: Chen, X., Li, M., Qiu, L., Yang, Q., Zhou, Y., Zhu, B., Wan, B., Liu, T., Hu, Z., and Liu, M.: Consequences of soil multitrophic biodiversity promoted by organic input management for ecosystem multifunctionality, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9338, https://doi.org/10.5194/egusphere-egu22-9338, 2022.

13:38–13:44
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EGU22-5532
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ECS
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Virtual presentation
Laura Morales, María Teresa Domínguez, and Elena Fernández-Boy

Climate change´s effect on soil functioning is a major concern in the Mediterranean basin, where rainfall will be likely reduced by 30% by the end of the century. Soil organic matter contributes to water balance by improving soil structure and aggregate stability, increasing water infiltration and holding capacity. Therefore, C-poor soils, as agricultural soils, might be more vulnerable to drought conditions. The addition of organic amendments increases soil organic matter and improves soil properties. The quality of the added substrate may determine soil microbial community structure and activity, which can also influence soil response to drought. The main objective was to evaluate the effect of the application of organic amendments with different quality (as indicated by their C:N ratio) on soil properties, plant development, and the resistance of soil functioning against simulated drought conditions. Hypothetically, the addition of a substrate with a high C:N ratio favours fungal dominance within the soil microbial community, which is usually related to a higher soil resistance.

An experiment was carried out in pot mesocosms under greenhouse conditions. Four organic substrates in a C:N ratio range were selected: 1) leonardite (LE, C:N = 57,8); 2) earthworm humus (HU, C:N = 15,6); 3) biosolid compost (BC, C:N = 8,8); and 4) dry biomass of Vicia faba (VF, C:N = 10,2). Their effect was compared with a non-amended control (NA). After amendment application, seeds of Lolium rigidum and Medicago polymorpha were sown, and a drought treatment was established. Half of the replicates received a 30 % less water supply, belonging to the drought treatment (DR), compared to the control (CT). The factorial experimental design resulted in 10 treatments with 10 replicates per treatment. A base-line soil sampling was done before the establishment of the drought treatment and repeated after 30 days, analysing soil biological properties (microbial biomass, enzyme activities, soil respiration rate). Soil moisture in the upper 5 cm was periodically measured.

Amendment addition improved some of the microbial activity indices in relation to non-amended soils, such as N-acetylglucosaminidase activity (in all the amended soils) and dehydrogenase activity (in HU and VF). Microbial biomass was greatly increased by amendment application (80 % increase). BC was the most efficient in improving soil water availability (32% higher than in NA), showing no significant differences in soil moisture between DR and CT. BC and VF amendments significantly reduced L. rigidum germination rate, and drought conditions significantly reduced plant growth compared to the control. However, by the end of the experiment, L. rigidum biomass in both treatments was higher than in the other treatments. M. polymorpha germination rate was also reduced in BC and VF, but only in LE drought conditions significantly affected plant development. Despite this, the simulated drought conditions did not result in a significant change in any of the soil functioning variables measured. In conclusion, organic amendments enhanced soil microbial activity in a C-poor agricultural soil but did not clearly improve soil response to a simulated drought event.

How to cite: Morales, L., Domínguez, M. T., and Fernández-Boy, E.: Effect of the addition of organic amendments to C-poor agricultural soils on soil resistance against drought, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5532, https://doi.org/10.5194/egusphere-egu22-5532, 2022.

13:44–13:50
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EGU22-1946
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Presentation form not yet defined
Shixiu Zhang, Liang Chang, Xuewen Chen, Yan Zhang, Xueming Yang, Shuxia Jia, and Aizhen Liang

Conservation tillage has become the core technology to conquer the degradation of black soil, the ‘giant panda in arable land’. Since soil is a home to a variety of organisms, it is very important to regard soil as a living system to evaluate the impact of conservation tillage on the health of black soil. Therefore, based on the long-term conservation tillage trial established by the Key Laboratory of Mollisols Agroecology of the Chinese Academy of Sciences, the responses of soil biodiversity and its function to conservation tillage were comprehensively elucidated in this study. Compared with conventional tillage, conservation tillage strongly improved the species richness (1-8%), density (25-57%), and biomass (30-50%) of the entire soil assemblages, including microorganisms, nematodes, collembolans, mites and earthworms, as well as the connectance of soil food web (14-32%). Furthermore, conservation tillage promotes the performance of soil biotic function in soil structure formation, soil carbon sequestration and nitrogen efficient utilization and crop yield stability. These results suggest that conservation tillage can effectively utilize the functional potential of soil organisms, which is of great significance to supporting the healthy and sustainable development of agriculture in the black soil region of northeast China.

How to cite: Zhang, S., Chang, L., Chen, X., Zhang, Y., Yang, X., Jia, S., and Liang, A.: Conservation tillage and soil biodiversity in the black soil region of northeast China: results from a long-term tillage trial, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1946, https://doi.org/10.5194/egusphere-egu22-1946, 2022.

13:50–13:56
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EGU22-9334
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ECS
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Virtual presentation
Innangi Michele, Antonietta Fioretto, Georg Guggenberger, Olga De Castro, Daniele De Luca, Emanuela Di Iorio, and Tiziana Danise

The issue of exploited soils that become unproductive after extended agriculture use is constantly growing and it is considered of great interest on a global level. Soil degradation induces loss of important ecosystem services and biodiversity, which is aggravated by the on-going climate change. Here, we investigated the chances of reforestation of an exploited soil as a possible nature based solution to this problem. We aimed at identifying a type of forest management capable of requalifying these soils. For that, we investigated a site in Central Italy characterized by a mixed-species plantation represented by tree different associations consisting of particular ancillary species, namely Alnus cordata, Elaeagnus umbellata (both N-fixing species), and Corylus avellana, in association with valuable species, such as Populus alba and Juglans regia planted on a former agricultural land. The criteria for the  improvement of soil quality was an increase in organic matter and biodiversity. We evaluated how the relationship between soil chemical and biological parameters varied among different intercropping systems and in a conventional agricultural field. We tested topsoil (0-10 cm) total organic carbon, total nitrogen, lignin and cellulose, as well as biological parameters such as fluorescein diacetate hydrolase (FDAH) enzyme activity, and fungal biodiversity by using a DNA metabarcoding approach. The comparison with the agricultural field revealed that revegetation led to an increase in both carbon and nitrogen as well as FDAH activity and fungal diversity. In this context, ancillary species could play a key role in restoring degraded soils quality, whereas N-fixing species Alnus cordata increased both soil fertility and biodiversity compared to the agricultural field and to other tree associations.

 

How to cite: Michele, I., Fioretto, A., Guggenberger, G., De Castro, O., De Luca, D., Di Iorio, E., and Danise, T.: From agriculture to forests: restoring fertility and biodiversity of exploited soils, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9334, https://doi.org/10.5194/egusphere-egu22-9334, 2022.

13:56–14:02
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EGU22-3500
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ECS
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Virtual presentation
Xiao fang Du, Han wen Liu, Ying bin Li, Xiao ke Zhang, and Wen ju Liang

Organic substitution can benefit to enhance soil health and maintain sustainable food production. Soil organisms play important roles in decomposing organic matter, recycling soil nutrients and resisting pests and diseases. However, the effect of soil biodiversity on soil multifunctionality of farmland ecosystem under organic substitution is still unclear. Here, we studied the shifts of soil biotic communities and soil multifunctionality (functions related with C, nutrient cycling and crop yield), and investigated soil biotic diversity-ecosystem function relationship under a 5-year field organic substitution experiment (30% nitrogen fertilizer substitute with straw, cattle manure and biochar, respectively). Our results showed that the highest value of soil multifunctionality was found in straw substitution treatment. Soil nematode community composition significantly associated with soil multifunctionality. We used structural equation modelling to identify the effects of soil biotic diversities and composition on multifunctionality. The SEM model predicted 74% of the variation in soil multifunctionality, and found that nematode community composition directly drove soil multifunctionality, whereas organic substitution and bacterial community composition could indirectly affect soil multifunctionality by changing soil nematode community. Our study has important implications for the contribution of soil biodiversity in driving multifunctionality of farmland ecosystem and for maintaining the sustainable development of agriculture.

How to cite: Du, X. F., Liu, H. W., Li, Y. B., Zhang, X. K., and Liang, W. J.: Effects of soil biodiversity on soil multifunctionality after 5-year organic substitutions in a Maize field, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3500, https://doi.org/10.5194/egusphere-egu22-3500, 2022.

14:02–14:08
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EGU22-9910
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ECS
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Virtual presentation
Maria Cid Rodriguez, Marco Cantonati, Daniel Spitale, and Claudio Zaccone

Peatlands are a major carbon (C) sink and represent important habitats for nature conservation because of the occurrence of specifically adapted organisms. Peatlands are typically nutrient-poor environments, and thus extremely sensitive to nitrogen (N) depositions. In fact, increasing N inputs can cause a shift from a Sphagnum moss- to a vascular plant-dominated vegetation as well as an alteration of the mire geochemistry which, in turn, affects the litter composition and decomposition rate. Peatland is an extremely fragile ecosystem: at the European level, >60% of this habitat type has been lost just in the last decades. In Alpine peatlands, in particular, overgrazing has been identified as a main problem for habitat integrity and biodiversity.

In the present study, six Belarus (50-cm deep) cores were collected from several peatlands located in the Adamello-Brenta Nature Park (Trentino, Italy) mirroring a grazing-induced disturbance gradient. All cores were cut frozen into 3-cm sections, and analysed for dry density, water content, pH, EC, and elemental (CHNS) composition. Diatom taphocoenoses were also determined. In particular, diatom frustules were prepared using hot hydrogen peroxide and finally mounted in the Naphrax© resin to produce permanent mounts for identifications and counts. 400 valves were counted and identified to the species level in each slide using a light microscope at x1000 magnification. The whole procedure was kept quantitative to allow the calculation of absolute abundances (n-valves/g-peat-dw).

Physical, chemical and biological parameters generally underlined how the grazing influence was clear mainly in the top 20 cm, and resulted in an increasing of density (up to 2×) and N concentration (up to 3×) as well as in a lower gravimetric water content (up to 50%). No significant differences were observed below 30 cm of depth.  More than 100 diatom species were identified throughout the 6 cores investigated, and several of them are included in threat categories of the Red List for central Europe (e.g., Cymbopleura valaiseana, Eunotia hexaglyphis, E. triodon). Since diatoms can reflect major regional environmental gradients, they can be used as indicators of ecological conditions in peatlands. In fact, some species that are trivial (= frequent and often abundant) in mire environments in spite of being relatively rare at the overall level of European inland waters (e.g., Aulacoseira alpigena, Encyonema perpusillum, Kobayasiella micropunctata) were found in the cores from highly-grazed areas whilst several rare and sensitive species were detected only (or were clearly more frequent) in cores from mildly-grazed areas.

This research can provide useful indications on the harmful effects of grazing in terms of both biogeochemical cycles and nature/habitats conservation.

How to cite: Cid Rodriguez, M., Cantonati, M., Spitale, D., and Zaccone, C.: Impact of cattle grazing on peat properties and diatoms, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9910, https://doi.org/10.5194/egusphere-egu22-9910, 2022.

14:08–14:14
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EGU22-1397
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Presentation form not yet defined
Jie Zhao, Jiangnan Li, and Kelin Wang

Reducing chemical fertilizers and agricultural residues substitution is a feasible practice to develop sustainable agriculture. However, there is a lack of evaluation on the ecosystem functioning and services of different reducing chemical fertilizers and agricultural residues substitution practices, as well as the roles of soil micro-food webs in sustainable agriculture. Here, we evaluated changes in crop yields, soil physico-chemical properties, soil micro-food web assembly, and ecosystem multifunctionality, and the contribution of soil micro-food web assembly to ecosystem multifunctionality under six long-term fertilization treatments: no fertilizer control, conventional chemical NPK fertilizers, and the reducing chemical NPK fertilizers and low- (30%) or high- (60%) levels of agricultural residues (i.e., straw or cattle manure) substitution. Our results showed that the reducing chemical fertilizers and agricultural residues substitution practices can maintain crop yields and improve soil fertility compared with chemical fertilizers application alone. The improvement of soil micro-food web was more obvious with the reducing chemical fertilizers and agricultural residues substitution practices, such as increased soil bacterial biomass, maintained soil biodiversity, and mitigated the negative effects of long-term chemical fertilizers application alone on soil micro-food web. More importantly, maintaining soil bacterial biomass, especiallly the beneficial microorganisms (e.g., Proteobacteria and Firmicutes), and bacterivorous nematode abundance is primarily important in  maintaining ecosystem multifunctionality. Overall, the reducing chemical fertilizers and agricultural residues substitution practices improved agroecosystem functioning and services and contributed to sustainable agriculture. 

How to cite: Zhao, J., Li, J., and Wang, K.: Linkages between soil micro-food webs and agroecosystem multifunctionality under organic and/or inorganic fertilization, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1397, https://doi.org/10.5194/egusphere-egu22-1397, 2022.

14:14–14:20
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EGU22-11805
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ECS
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Virtual presentation
Padma Ladon and Satish Chandra Garkoti

The extreme biophysical and climatic conditions in the trans-Himalayan region of Ladakh limits the plant growth and therefore since, time immemorial, high altitude pastures has been utilized for food and fodder security along with crop farming. The study investigated the changes in the concentration of organic carbon (C), nitrogen (N) and phosphorus (P), potassium (K) and ph in soil of high altitude pastures along the altitudinal gradient (4000 to 5500m amsl) in Leh Ladakh, India. Three sites were chosen for the study: Gya pasture (4500-5500 m), Shang pasture (4200-5000 m) and Igoo pasture (4000 to 4800 m). The results showed that concentration of soil organic carbon C and total nitrogen increased with increasing altitude in all the three sites. The concentration of available phosphorus P and available potassium K slightly decreased and had a non-linear relationship, however in case of Igoo pasture, the P and K value increased with increasing altitude. While the ph remained towards basic (ph= 7-8) irrespective of the site and elevational change. Besides the elevation, the practice of livestock grazing during summer migration could also impact the soil nutrient concentration as higher nitrogen and carbon content is observed near the temporary settlements of the herders in the sites where the practice was still intact.

How to cite: Ladon, P. and Garkoti, S. C.: Soil nutrient concentration with increasing elevational pattern in high altitude pastures in Leh Ladakh, India., EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11805, https://doi.org/10.5194/egusphere-egu22-11805, 2022.

14:20–14:26
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EGU22-10834
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ECS
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Presentation form not yet defined
Nan Jin, Xin Gong, Jiman Li, Xiaoyun Chen, Di Wu, Feng Hu, and Manqiang Liu

Soil fauna are now recognized as key components of soil and plant health, but how soil fauna modulates or even dictates plant stress responses remains unknown.Prior studies found the impacts of soil fauna on the plantprioritize either growth or defence depends on the feeding types of herbivores, suggesting that aboveground responses to herbivores and soil fauna are interconnected.However, the molecular and metabolism mechanism underlying this relationship is unclear.Theoretically, soil biotic interactions modified by soil fauna can drive above-ground responses, but there is still shortage of experimental evidence. Here, we aimed to test whether and how the plant survival strategies subjective to different feeding types of herbivores, were affected by rhizosphere microbial interactions exerted by soil fauna. We hypothesized that aboveground stress responses in plants can be orchestrated through coordinating belowground biotic interaction by soil fauna-root commensals.

First, we set out a complete factor design experiment under field condition by manipulating earthworms (Metaphire guillelmi) and the types of above-ground insects (cell-feeding, thrips: Frankliniella occidentalis; phloem-sucking, aphid: Myzus persicae). Soil physicochemical analysis and leaf RNA-seq were used to expound how earthworms dictates the trade-off between plant growth and defence. Second, to further explore the soil biotic-mediate pathway in the presence of earthworms. A microcosm experiment was performed by using a re-inoculated different soil community (obtained from 1000 and 20 μm sieves, respectively) collected from the field, with and without earthworms in the absence of herbivores. We used amplicon sequencing and plant metabolite analysis to elucidate how earthworm function by shaping rhizosphere biotic interactions.

We report here that belowground commensals can orchestrate aboveground stress responses in plants through biotic interaction. Earthworms suppressed thrips number, consistent with a resource-cost model. Contrary, earthworms promoted aphids’ number through the hormone antagonism model. Notably, soil biotic properties affected plant performance rather than soil abiotic properties mediated by earthworm. The microcosm experiment verified that rhizosphere microbial diversity and community structure shaped by earthworms reformed plant performance. In inoculated soil conditioned by earthworms, soil microbiome tended to be bacterial community towards primary metabolic processes, strengthening the interaction between fungi and bacteria in the rhizosphere. Further, the strengthened rhizosphere microbial interactions were increased plant shoot biomass and soluble sugar accumulation but decreased JA content. Taken together, effects of soil fauna on plant growth-defence relationships depend on the feeding types of herbivores, mainly attributing to the shifts in rhizosphere microbial interactions. Phenotypic plasticity and aboveground stress responses in plants can therefore be governed by soil fauna-root commensals.

How to cite: Jin, N., Gong, X., Li, J., Chen, X., Wu, D., Hu, F., and Liu, M.: Soil fauna modify plant growth-defence relationships through coordinating rhizosphere microbial interactions, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10834, https://doi.org/10.5194/egusphere-egu22-10834, 2022.

14:26–14:32
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EGU22-12360
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ECS
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Virtual presentation
Maeva Labouyrie, Ferran Romero, Panos Panagos, Arwyn Jones, Leho Tedersoo, Cristiano Ballabio, Emanuele Lugato, Marcel van der Heijden, and Alberto Orgiazzi

The global area of cultivated land has increased considerably over the past five decades. Despite the many ecosystem services provided by soil, at large-scale, it is still poorly understood whether land-use intensification influences soil life and the services that rely upon it. Here we used an extensive soil metabarcoding database, derived from the European Union’s (EU) Land Use/Cover Area frame statistical Survey (LUCAS), to assess how vegetation (land) cover, biogeographic factors (i.e., climate) and soil properties influence the structure and potential functions of bacterial and fungal communities at a continental scale. We selected 715 LUCAS sampling locations, classified according to an increasing land-use intensification: from woodland (less disturbed), to grassland, and cropland (more disturbed). We found that croplands and grasslands had a higher microbial richness than woodlands. We observed that bacteria and fungi were not driven by the same environmental variables. While soil properties (e.g. pH, C:N ratio, potassium, phosphorus and carbonate contents) drove bacterial community composition, vegetation cover was the main driver for the fungal community. We found that vegetation cover, biogeographic factors and soil properties differently determined the distribution of main functional groups; for example, cropland soils with a higher pH and a lower C:N ratio hosted more nitrogen fixing bacteria whereas woodlands were dominated by ectomycorrhizal fungi, especially in non-compacted clay soils, with lower C:N ratio and potassium content. We observed that increasing aridity may inhibit functions beneficial for the plant communities (i.e. bacterial chemoheterotrophy and nitrogen fixation, arbuscular mycorrhizal symbiosis) and favour the spread of fungal pathogens. In addition, a high diversity was not always a positive aspect for ecosystem functioning, as for example, croplands were characterized by a higher presence of fungal pathogens. Maps of microbial functional groups for the EU were also generated. In conclusion, our results represent a step forward to a more comprehensive assessment of soil microbial diversity and associated functions across the European Union. Beside possible ecological implications, our findings can contribute to the development of indicators and implementation of soil management policies.

 

How to cite: Labouyrie, M., Romero, F., Panagos, P., Jones, A., Tedersoo, L., Ballabio, C., Lugato, E., van der Heijden, M., and Orgiazzi, A.: Soil microbial diversity and ecosystem functioning assessment across Europe, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12360, https://doi.org/10.5194/egusphere-egu22-12360, 2022.

14:32–14:38
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EGU22-12402
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ECS
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Presentation form not yet defined
Julia Köninger, Panos Panagos, Maria J.I. Briones, and Alberto Orgiazzi

Despite that all above-ground life depends on that below-ground, the knowledge on soil biodiversity is still very limited. Conservation activities have been often postponed due to missing data. For example, this was the case in previous EU Common Agricultural Policy agreements, when environmental indicators for soil biodiversity were meant to be integrated comparable to biodiversity indicators in place. While massive sequencing of soil biodiversity contributes significantly to shredding light on below-ground life, sampling methods are not adequately harmonised, preventing the establishment of reliable quantifiable conservation targets. In addition, broad-scale studies are often biased towards microorganisms and hence, in the majority of the published literature, eukaryotes, and more specifically, animals and protists, are neglected. Therefore, in a first EU-wide study of 885 sites, we investigated the response of environmental factors (i.e., soil properties, biogeographical location and climate) and land cover (cropland, grassland and woodland) on soil eukaryotic diversity. The LUCAS survey and previously published studies provided soil, climate and land cover data. DNA metabarcoding of the 18S genes allowed us to assess the diversity of animals, protists and fungi, but due to their high variability in body size, we grouped them into micro-, meso- and macrofauna. For the bioinformatics analyses, we clustered sequence reads into amplicon sequence variants using DADA2 and thereafter, we assessed alpha and beta diversity and the relationships between eukaryotic diversity and environmental drivers using regression, ordination, and variance partitioning analyses. Our results allowed us to identify potential indicator species for EU soils, representing the effect of different drivers on eukaryotic diversity. These findings will help to understand the links between soil abiotic and biotic patterns at large scale, pathing the way for quantifiable goals to be included in conservation activities and policies.

How to cite: Köninger, J., Panagos, P., Briones, M. J. I., and Orgiazzi, A.: Soil Eukaryotes Diversity in the EU - Environmental drivers in agricultural land, forests and grasslands, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12402, https://doi.org/10.5194/egusphere-egu22-12402, 2022.