SSS4.4

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.

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 networks^4,5, 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.

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.

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.

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.

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 MicroResp^ТМ 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.

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.

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.

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.

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.

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.

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.

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.

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.

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.