{"type": "FeatureCollection", "features": [{"id": "10.1002/ajb2.70086", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-07-27T16:14:17Z", "type": "Journal Article", "created": "2025-08-12", "title": "Moss\u2010cyanobacteria associations: A model for studying symbiotic interactions and evolutionary strategies", "keywords": ["forests", "mosses", "non-vascular plants", "nitrogen fixation", "symbioses", "On the Nature of Things", "cyanobacteria", "model organisms"], "contacts": [{"organization": "Kathrin Rousk", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.1002/ajb2.70086"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/American%20Journal%20of%20Botany", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1002/ajb2.70086", "name": "item", "description": "10.1002/ajb2.70086", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1002/ajb2.70086"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2025-08-01T00:00:00Z"}}, {"id": "10.1007/s00248-024-02363-6", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-07-27T16:14:40Z", "type": "Journal Article", "created": "2024-03-01", "title": "The Feather Moss Hylocomium splendens Affects the Transcriptional Profile of a Symbiotic Cyanobacterium in Relation to Acquisition and Turnover of Key Nutrients", "description": "Abstract

Moss-cyanobacteria symbioses were proposed to be based on nutrient exchange, with hosts providing C and S while bacteria provide N, but we still lack understanding of the underlying molecular mechanisms of their interactions. We investigated how contact between the ubiquitous moss Hylocomium splendens and its cyanobiont affects nutrient-related gene expression of both partners. We isolated a cyanobacterium from H. splendens and co-incubated it with washed H. splendens shoots. Cyanobacterium and moss were also incubated separately. After 1\uffc2\uffa0week, we performed acetylene reduction assays to estimate N2 fixation and RNAseq to evaluate metatranscriptomes. Genes related to N2 fixation and the biosynthesis of several amino acids were up-regulated in the cyanobiont when hosted by the moss. However, S-uptake and the biosynthesis of the S-containing amino acids methionine and cysteine were down-regulated in the cyanobiont while the degradation of selenocysteine was up-regulated. In contrast, the number of differentially expressed genes in the moss was much lower, and almost no transcripts related to nutrient metabolism were affected. It is possible that, at least during the early stage of this symbiosis, the cyanobiont receives few if any nutrients from the host in return for N, suggesting that moss\uffe2\uff80\uff93cyanobacteria symbioses encompass relationships that are more plastic than a constant mutualist flow of nutrients.Abstract

Moss-associated nitrogen (N2) fixation is one of the main inputs of new N in pristine ecosystems that receive low amounts of atmospheric N deposition. Previous studies have shown that N2 fixation is inhibited by inorganic N (IN) inputs, but if N2 fixation in mosses is similarly affected by organic N (ON) remains unknown. Here, we assessed N2 fixation in two dominant mosses in boreal forests (Pleurozium schreberi and Sphagnum capillifolium) in response to different levels of N, simulating realistic (up to 4 kg N ha\u22121 yr\u22121) and extreme N deposition rates in pristine ecosystems (up to 20 kg N ha\u22121 yr\u22121) of IN (NH4NO3) and ON (alanine and urea). We also assessed if N2 fixation can recover from the N additions. In the realistic scenario, N2 fixation was inhibited by increasing NH4NO3 additions in P. schreberi but not in S. capillifolium, and alanine and urea stimulated N2 fixation in both moss species. In contrast, in the extreme N additions, increasing N inputs inhibited N2 fixation in both moss species and all N forms. Nitrogen fixation was more sensitive to N inputs in P. schreberi than in S. capillifolium and was higher in the recovery phase after the realistic compared to the extreme N additions. These results demonstrate that N2 fixation in mosses is less sensitive to organic than inorganic N inputs and highlight the importance of considering different N forms and species-specific responses when estimating the impact of N inputs on ecosystem functions such as moss-associated N2 fixation.

", "keywords": ["0301 basic medicine", "0303 health sciences", "03 medical and health sciences", "Sphagnum", "Nitrogen fixation", "Nitrogen pollution", "Organic nitrogen", "15. Life on land", "Cyanobacteria", "Feathermosses"]}, "links": [{"href": "https://doi.org/10.1007/s10533-022-00920-0"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Biogeochemistry", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1007/s10533-022-00920-0", "name": "item", "description": "10.1007/s10533-022-00920-0", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1007/s10533-022-00920-0"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2021-11-08T00:00:00Z"}}, {"id": "10.1007/s10705-007-9121-7", "type": "Feature", "geometry": null, "properties": {"license": "Closed Access", "updated": "2026-07-27T16:15:06Z", "type": "Journal Article", "created": "2007-07-04", "title": "Effects Of Cropping History And Phosphorus Source On Yield And Nitrogen Fixation In Sole And Intercropped Cowpea\u2013Maize Systems", "description": "Symbiotic N2-fixation, N uptake efficiency, biomass- and crop production of cowpea and maize as affected by P source, sole- and intercropped, and introduction of break crops were studied on a farmer\u2019s fields in semi-arid Tanzania. Cowpea fixed around 60% of its N from the atmosphere amounting to 70\u00a0kg N\u00a0ha\u22121 under sole and 36\u00a0kg N\u00a0ha\u22121 under intercropping as estimated by the 15N isotope dilution method around peak biomass production. The amount of N2-fixed was 30\u201340% higher when P was applied as either TSP or MRP whereas cowpea yield were unaffected. Intercropped maize with 19,000 plant ha\u22121 accumulated the same amount of N as 38,000 sole cropped maize plants although intercropping reduced the dry matter accumulation by 25%. The N uptake efficiency of the applied 15N labelled fertiliser was 26%, which equal a total pool of early available plant N of 158\u00a0kg N\u00a0ha\u22121. Under the N deficient conditions, P application did not increase the grain yield of maize. The LER indicate that sole cropping required 18% more area than intercropping in order to produce the same grain yield, and 35% more land when LER was based on N uptakes. Introduction of break crops in the maize systems, more than doubled accumulation of dry matter and N in the grain compared to continuous maize cropping. During maturation sole crop cowpea shedded leaves containing 41\u00a0kg N ha\u22121. The current findings underline the importance of crop diversity in Sub Saharan Africa agriculture and emphasise the need for including all residues, including shedded leaves, in nutrient balance studies.", "keywords": ["2. Zero hunger", "Intercropping", "Nitrogen fixation", "/dk/atira/pure/core/keywords/Life", "LER", "Semi-arid", "Cowpea", "0401 agriculture", " forestry", " and fisheries", "04 agricultural and veterinary sciences", "15. Life on land", "Former LIFE faculty", "Maize"]}, "links": [{"href": "https://doi.org/10.1007/s10705-007-9121-7"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Nutrient%20Cycling%20in%20Agroecosystems", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1007/s10705-007-9121-7", "name": "item", "description": "10.1007/s10705-007-9121-7", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1007/s10705-007-9121-7"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2007-07-05T00:00:00Z"}}, {"id": "10.1007/s10750-009-9715-y", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-07-27T16:15:09Z", "type": "Journal Article", "created": "2009-02-13", "title": "Heterotrophic Nitrogen Fixation In Oligotrophic Tropical Marshes: Changes After Phosphorus Addition", "description": "In order to determine the impact of nutrient enrichment on phosphorus (P) limited wetlands, we established experimental P additions in marshes throughout northern Belize. P significantly increased macrophyte primary production, which led to the rapid elimination of cyanobacterial mats. The replacement of cyanobacterial mats by macrophytes constrained autotrophic nitrogen (N) fixation, increased the quantity, and changed the quality of organic matter input to the sediments. We predicted that the activity of sediment heterotrophic N fixers will be impacted by these alterations in carbon input. We used the acetylene reduction technique to measure potential (glucose amended) nitrogenase activity (NA) in sediments from controls and treatment plots that have been P enriched for four years and dominated either by Eleocharis cellulosa, or Typha domingensis for two years. NA in P-enriched plots was 2\u20133 orders of magnitude higher than NA in controls. NA was positively correlated with the soil reactive P, both total organic and microbial carbon, live root biomass, and total phospholipid fatty acids (PLFA) as an indicator of active microbial biomass. It was negatively correlated with the concentration of ammonium-N. Path analysis revealed that the indirect effect of P on NA through the root biomass was more important than the direct effect of P. NA of the upper sediment layer was consistently higher in Eleocharis than in Typha dominated plots, despite the higher litter input by Typha. We feel that the higher levels of lignin and phenolics occurring in Typha litter, relative to Eleocharis, constrained NA in Typha plots.", "keywords": ["0106 biological sciences", "Freshwater & Marine Ecology", "Salinity", "Ecology", "Life Sciences", "Phosphorus", "04 agricultural and veterinary sciences", "Aquatic Science", "15. Life on land", "Cyanobacteria", "Pollution", "01 natural sciences", "6. Clean water", "Environmental Science(all)", "13. Climate action", "Heterotrophic nitrogen fixation", "0401 agriculture", " forestry", " and fisheries", "Zoology", "Typha", "Eleocharis"], "contacts": [{"organization": "\u010cern\u00e1, Barbora, Rejm\u00e1nkov\u00e1, Eli\u0161ka, Snyder, Jenise M., \u0160antr\u016f\u010dkov\u00e1, Hana,", "roles": ["creator"]}]}, "links": [{"href": "https://escholarship.org/content/qt0xk5x7sm/qt0xk5x7sm.pdf"}, {"href": "https://doi.org/10.1007/s10750-009-9715-y"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Hydrobiologia", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1007/s10750-009-9715-y", "name": "item", "description": "10.1007/s10750-009-9715-y", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1007/s10750-009-9715-y"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2009-02-13T00:00:00Z"}}, {"id": "10.1007/s11104-005-0194-2", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-27T16:15:10Z", "type": "Journal Article", "created": "2012-03-12", "title": "Long-Term Integrated Soil Fertility Management In South-Western Nigeria: Crop Performance And Impact On The Soil Fertility Status", "description": "Crop response, tree biomass production and changes in soil fertility characteristics were monitored in a long-term (1986\u20132006) alley-cropping trial in Ibadan, Nigeria. The systems included two alley cropping systems with Leucaena leucocephala and Senna siamea on the one hand and a control (no-trees) system on the other hand, all cropped annually with a maize- cowpea rotation. All systems had a plus and minus fertilizer treatment. Over the years, the annual biomass return through tree prunings declined steadily, but more drastically for Leucaena than for Senna. In 2002, the nitrogen contribution from Leucaena residues stabilized at about 200 kg N/ha/year, while the corresponding value for Senna was about 160 kg N/ha/year. On average, the four Leucaena prunings were more equal in biomass as well as in amounts of N, P and cations, while the first Senna pruning was always contributing up to 60% of the annual biomass or nutrient return. Maize crop yields declined steadily in all treatments, but the least so in the Senna + fertilizer treatment where in 2002 still 2.2 t/ha of maize were obtained. Nitrogen fertilizer use efficiency was usually higher in the Senna treatment compared to the control or the Leucaena treatment. Added benefits due to the combined use of fertilizer N and organic matter additions were observed only for the Senna treatment and only in the last 6 years. At all other times, they remained absent or were even negative in the Leucaena treatments for the first 3 years. Most chemical soil fertility parameters decreased in all the treatments, but less so in the alley cropping systems. The presence of trees had a positive effect on remaining carbon stocks, while they were reduced compared to the 1986 data. Trees had a positive effect on the maintenance of exchangeable cations in the top soil. Exchangeable Ca, Mg and K \u2013 and hence ECEC \u2013 were only slightly reduced after 16 years of cropping in the tree-based systems, and even increased in the Senna treatments. In the control treatments, values for all these parameters reduced to 50% or less of the original values after 20 years. All the above points to the Senna-based alley system with fertilizers as the more resilient one. This is reflected in all soil fertility parameters, in added benefits due to the combined use of fertilizer nitrogen and organic residue application and in a more stable maize yield over the years, averaging 2.8 t/ha with maximal deviations from the average not exceeding 21%.", "keywords": ["alley cropping", "0106 biological sciences", "added benefits", "fertilizers", "senna siamea", "yields", "dry matter content", "fertilidad del suelo", "maize", "01 natural sciences", "nitrogen use efficiency", "cowpeas", "ma\u00edz", "zea mays", "vigna unguiculata", "propiedades f\u00edsico - qu\u00edmicas suelo", "aplicaci\u00f3n de abonos", "hedgerow", "fijaci\u00f3n del nitr\u00f3geno", "2. Zero hunger", "biomass", "caup\u00ed", "soil chemicophysical properties", "nutrient", "soil fertility", "fertilizer application", "04 agricultural and veterinary sciences", "15. Life on land", "6. Clean water", "biomasa", "leucaena leucocephala", "nitrogen fixation", "cultivo entre l\u00edneas", "0401 agriculture", " forestry", " and fisheries", "rendimiento", "contenido de materia seca"]}, "links": [{"href": "http://ciat-library.ciat.cgiar.org/Articulos_Ciat/D2-PDF.pdf"}, {"href": "https://doi.org/10.1007/s11104-005-0194-2"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Plant%20and%20Soil", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1007/s11104-005-0194-2", "name": "item", "description": "10.1007/s11104-005-0194-2", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1007/s11104-005-0194-2"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2005-06-01T00:00:00Z"}}, {"id": "10.1007/s11104-012-1411-4", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-27T16:15:17Z", "type": "Journal Article", "created": "2012-08-14", "title": "Biochar Application Reduces Nodulation But Increases Nitrogenase Activity In Clover", "description": "Background and aims: Biochar is produced from the pyrolysis of organic materials, and when buried in soil can act as a long term soil carbon (C) store. Evidence suggests that biochar can also increase crop yields, reduce nutrient leaching and increase biological nitrogen fixation in leguminous plants. However, the potential for increasing biological N2 fixation in agroecosystems is poorly understood, with inconsistent reports of root nodulation following biochar application. Therefore, the aim of this study was to determine the effect of biochar application rate and time since application on nodulation and nitrogenase activity in nodules of clover grown in a temperate agricultural soil. Methods: We used replicated field plots with three biochar application rates (0, 25 and 50 t ha-1). Three years after biochar amendment, the plots were further split and fresh biochar added at two different rates (25 and 50 t ha-1) resulting in double-loaded reapplications of 25 + 25 and 50 + 50 t ha-1. Results: Three years after biochar application, there was no significant difference in the total number of root nodules between biochar-amended and unamended soil, regardless of the application rate. However, despite clover root nodules being of a similar number and size the level of nitrogenase activity of individual nodules in biochar-amended soil was significantly higher than in unamended soil. Reapplication of biochar resulted in decreased nodulation, although the rate of nitrogenase activity per nodule remained unaffected. Conclusion: In the short term, biochar influences root nodule number and localised N2 fixation per nodule; however, total nitrogenase activity for the whole root system remained unaffected by the application rate of biochar or time since its application. These results emphasise the importance of long-term field studies, with a variety of applications rates for determining the influence of biochar applications on N2-fixing organisms and in providing data that can meaningfully inform agronomic management decisions and climate change mitigation strategies.", "keywords": ["Carbon sequestration", "2. Zero hunger", "Climate change mitigation", "Legume-Rhizobia symbiosis", "13. Climate action", "Black nitrogen", "0401 agriculture", " forestry", " and fisheries", "Biological nitrogen fixation", "04 agricultural and veterinary sciences", "15. Life on land", "630", "Long term biochar trial", "6. Clean water"]}, "links": [{"href": "http://dspace.stir.ac.uk/bitstream/1893/18417/1/Plant%20Soil%202013.pdf"}, {"href": "https://doi.org/10.1007/s11104-012-1411-4"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Plant%20and%20Soil", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1007/s11104-012-1411-4", "name": "item", "description": "10.1007/s11104-012-1411-4", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1007/s11104-012-1411-4"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2012-08-15T00:00:00Z"}}, {"id": "10.1016/j.envexpbot.2025.106262", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-07-27T16:16:23Z", "type": "Journal Article", "created": "2025-10-26", "title": "Is moss-associated nitrogen fixation controlled by the same factors across shoots, species and sites?", "description": "

Biological N2 fixation performed by moss-associated cyanobacteria is among the main sources of new nitrogen (N) input in pristine subarctic ecosystems. Yet, until now there has been a lack of knowledge on the drivers of biological N2 fixation on small spatial scales (moss segment) in relation to the drivers at larger scales (moisture ecosystem). To investigate this, we assessed the capacity of N2 fixation along shoots of two common moss species, Pleurozium schreberi and Hylocomium splendens, collected along a steep precipitation gradient in the Subarctic. Furthermore, concentrations of nutrients and pH were analysed along the same moss shoot-gradients. We found the highest nitrogenase activity in H. splendens collected at the location with the highest mean annual precipitation. Nitrogenase activity varied significantly along the moss shoots, and between species and location along the precipitation gradient. P. schreberi had the highest nitrogenase activity in the middle segments, while for H. splendens , it was highest in the lowest segments (below 3\u202fcm). Contents of iron, molybdenum and N generally increased with moss segment depth, but phosphorus concentrations decreased and pH was stable across segments. Taken together, the factors that drive nitrogenase activity at small scales differ between moss species, whereas precipitation predominantly controls nitrogenase activity at larger scales (across habitats).

", "keywords": ["Hylocomium splendens", "Arctic", "Nitrogen fixation", "Bryophytes", "Pleurozium schreberi", "Precipitation", "Limiting nutrients"], "contacts": [{"organization": "J\u00f8rgen Ulrik Graudal Levinsen, Mingyue Yuan, Anders Michelsen, Kathrin Rousk,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.1016/j.envexpbot.2025.106262"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Environmental%20and%20Experimental%20Botany", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1016/j.envexpbot.2025.106262", "name": "item", "description": "10.1016/j.envexpbot.2025.106262", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1016/j.envexpbot.2025.106262"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2025-11-01T00:00:00Z"}}, {"id": "10.1016/j.envpol.2017.06.102", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-07-27T16:16:25Z", "type": "Journal Article", "created": "2017-07-13", "title": "Using nitrogen concentration and isotopic composition in lichens to spatially assess the relative contribution of atmospheric nitrogen sources in complex landscapes", "description": "Reactive nitrogen (Nr) is an important driver of global change, causing alterations in ecosystem biodiversity and functionality. Environmental assessments require monitoring the emission and deposition of both the amount and types of Nr. This is especially important in heterogeneous landscapes, as different land-cover types emit particular forms of Nr to the atmosphere, which can impact ecosystems distinctively. Such assessments require high spatial resolution maps that also integrate temporal variations, and can only be feasibly achieved by using ecological indicators. Our aim was to rank land-cover types according to the amount and form of emitted atmospheric Nr in a complex landscape with multiple sources of N. To do so, we measured and mapped nitrogen concentration and isotopic composition in lichen thalli, which we then related to land-cover data. Results suggested that, at the landscape scale, intensive agriculture and urban areas were the most important sources of Nr to the atmosphere. Additionally, the ocean greatly influences Nr in land, by providing air with low Nr concentration and a unique isotopic composition. These results have important consequences for managing air pollution at the regional level, as they provide critical information for modeling Nr emission and deposition across regional as well as continental scales.", "keywords": ["2. Zero hunger", "Air Pollutants", "Lichens", "Nitrogen Isotopes", "Portugal", "Atmosphere", "Nitrogen", "Urbanization", "Geographic Mapping", "Agriculture", "15. Life on land", "01 natural sciences", "6. Clean water", "Reactive nitrogen", "13. Climate action", "Nitrogen Fixation", "11. Sustainability", "Industry", "Isoscapes", "14. Life underwater", "Polution - Eutrophication", "Ecosystem", "Environmental Monitoring", "0105 earth and related environmental sciences"]}, "links": [{"href": "https://doi.org/10.1016/j.envpol.2017.06.102"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Environmental%20Pollution", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1016/j.envpol.2017.06.102", "name": "item", "description": "10.1016/j.envpol.2017.06.102", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1016/j.envpol.2017.06.102"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2017-11-01T00:00:00Z"}}, {"id": "10.1111/1462-2920.13954", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-07-27T16:19:18Z", "type": "Journal Article", "created": "2022-10-18", "title": "Application of stable-isotope labelling techniques for the detection of active diazotrophs", "description": "Summary

Investigating active participants in the fixation of dinitrogen gas is vital as N is often a limiting factor for primary production. Biological nitrogen fixation is performed by a diverse guild of bacteria and archaea (diazotrophs), which can be free\uffe2\uff80\uff90living or symbionts. Free\uffe2\uff80\uff90living diazotrophs are widely distributed in the environment, yet our knowledge about their identity and ecophysiology is still limited. A major challenge in investigating this guild is inferring activity from genetic data as this process is highly regulated. To address this challenge, we evaluated and improved several 15N\uffe2\uff80\uff90based methods for detecting N2 fixation activity (with a focus on soil samples) and studying active diazotrophs. We compared the acetylene reduction assay and the 15N2 tracer method and demonstrated that the latter is more sensitive in samples with low activity. Additionally, tracing 15N into microbial RNA provides much higher sensitivity compared to bulk soil analysis. Active soil diazotrophs were identified with a 15N\uffe2\uff80\uff90RNA\uffe2\uff80\uff90SIP approach optimized for environmental samples and benchmarked to 15N\uffe2\uff80\uff90DNA\uffe2\uff80\uff90SIP. Lastly, we investigated the feasibility of using SIP\uffe2\uff80\uff90Raman microspectroscopy for detecting 15N\uffe2\uff80\uff90labelled cells. Taken together, these tools allow identifying and investigating active free\uffe2\uff80\uff90living diazotrophs in a highly sensitive manner in diverse environments, from bulk to the single\uffe2\uff80\uff90cell level.

", "keywords": ["Spectrum Analysis", " Raman", "BIOLOGICAL SOIL CRUSTS", "106005 Bioinformatik", "106023 Molekularbiologie", "Nitrogen Fixation", "REVEALS", "FLUORESCENCE", "Research Articles", "Soil Microbiology", "106022 Mikrobiologie", "SPECTROSCOPY", "Bacteria", "Nitrogen Isotopes", "106003 Biodiversity research", "106023 Molecular biology", "GENETIC-REGULATION", "Archaea", "6. Clean water", "SURFACE-ENHANCED RAMAN", "COMMUNITY", "106003 Biodiversit\u00e4tsforschung", "13. Climate action", "Isotope Labeling", "106022 Microbiology", "NITROGEN-FIXATION", "106005 Bioinformatics", "RIBOSOMAL-RNA", "N-2 FIXATION"]}, "links": [{"href": "https://onlinelibrary.wiley.com/doi/pdf/10.1111/1462-2920.13954"}, {"href": "https://doi.org/10.1111/1462-2920.13954"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Environmental%20Microbiology", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1111/1462-2920.13954", "name": "item", "description": "10.1111/1462-2920.13954", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1111/1462-2920.13954"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2017-12-15T00:00:00Z"}}, {"id": "10.1016/j.jhazmat.2009.12.035", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-27T16:16:58Z", "type": "Journal Article", "created": "2009-12-18", "title": "In Situ Phytostabilisation Of Heavy Metal Polluted Soils Using Lupinus Luteus Inoculated With Metal Resistant Plant-Growth Promoting Rhizobacteria", "description": "The aim of this work is the evaluation of metal phytostabilisation potential of Lupinus luteus inoculated with Bradyrhizobium sp. 750 and heavy metal resistant PGPRs (plant-growth promoting rhizobacteria), for in situ reclamation of multi-metal contaminated soil after a mine spill. Yellow lupines accumulated heavy metals mainly in roots (Cu, Cd and especially Pb were poorly translocated to shoots). This indicates a potential use of this plant in metal phytostabilisation. Furthermore, As accumulation was undetectable. On the other hand, zinc accumulation was 10-100 times higher than all other metals, both in roots and in shoots. Inoculation with Bradyrhizobium sp. 750 increased both biomass and nitrogen content, indicating that nitrogen fixation was effective in soils with moderate levels of contamination. Co-inoculation of lupines with a consortium of metal resistant PGPR (including Bradyrhizobium sp., Pseudomonas sp. and Ochrobactrum cytisi) produced an additional improvement of plant biomass. At the same time, a decrease in metal accumulation was observed, both in shoots and roots, which could be due to a protective effect exerted on plant rhizosphere. Our results indicate the usefulness of L. luteus inoculated with a bacterial consortium of metal resistant PGPRs as a method for in situ reclamation of metal polluted soils.", "keywords": ["Chemical Hazard Release", "15. Life on land", "Plant Roots", "01 natural sciences", "Mining", "6. Clean water", "Lupinus", "Biodegradation", " Environmental", "13. Climate action", "Metals", " Heavy", "Nitrogen Fixation", "Soil Pollutants", "Decontamination", "Rhizobium", "0105 earth and related environmental sciences"], "contacts": [{"organization": "Antonio J. Palomares, Antonio J. Palomares, M.A. Chamber-P\u00e9rez, Elo\u00edsa Pajuelo, Mohammed Dary,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.1016/j.jhazmat.2009.12.035"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Journal%20of%20Hazardous%20Materials", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1016/j.jhazmat.2009.12.035", "name": "item", "description": "10.1016/j.jhazmat.2009.12.035", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1016/j.jhazmat.2009.12.035"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2010-05-01T00:00:00Z"}}, {"id": "10.1016/j.scitotenv.2022.156952", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-27T16:17:14Z", "type": "Journal Article", "created": "2022-06-22", "title": "Integrated organic and inorganic fertilization and reduced irrigation altered prokaryotic microbial community and diversity in different compartments of wheat root zone contributing to improved nitrogen uptake and wheat yield", "description": "Open AccessThe effect of long-term water and integrated fertilization on prokaryotic microorganisms and their regulation for crop nutrient uptake remains unknown. Therefore, the impact of soil water and integrated fertilization after eight years on prokaryotic microbial communities in different compartments of root zone and their association with wheat nitrogen (N) absorption and yield were investigated. The results showed that compared with fertilization treatments (F), water regimes (W) more drastically modulated the prokaryotic microbial community structure and diversity in bulk soil, rhizosphere and endosphere. The increase of irrigation improved the prokaryotic diversity in the rhizosphere and endosphere while decreased the diversity in the bulk soil. Application of organic fertilizers significantly improved soil organic matter (SOM) and nutrient contents, increased rhizosphere and endophytic prokaryotic microbial diversity, and elevated the relative abundance of aerobic ammonia oxidation and nitrification-related functional microorganisms in rhizosphere and endosphere. Increasing irrigation elevated the relative abundance of functional microorganisms related to aerobic ammonia oxidation and nitrification in the rhizosphere and endosphere. Soil water content (SWC) and NH4+-N as well as NO3\u2212-N were key predictors of prokaryotic microbial community composition under W and F treatments, respectively. Appropriate application of irrigation and organic fertilizers increased the relative abundance of some beneficial bacteria such as Flavobacterium. Water and fertilization treatments regulated the prokaryotic microbial communities of bulk soil, rhizosphere and endosphere by altering SWC and SOM, and provided evidence for the modulation of prokaryotic microorganisms to promote nitrogen uptake and wheat yield under long-term irrigation and fertilization. Conclusively, the addition of organic manure (50 %) with inorganic fertilizers (50 %) and reduced amount of irrigation (pre-sowing and jointing-period irrigation) decreased the application amount of chemical fertilizers and water, while increased SOM and nutrient content, improved prokaryotic diversity, and changed prokaryotic microbial community structure in the wheat root zone, resulting in enhanced nutrient uptake and wheat yield.", "keywords": ["0106 biological sciences", "Yield", "Microorganism", "Microbial population biology", "Nitrogen", "Soil Science", "Organic chemistry", "Plant Science", "01 natural sciences", "Environmental science", "Agricultural and Biological Sciences", "Soil", "Symbiotic Nitrogen Fixation in Legumes", "Soil water", "Genetics", "Fertilizers", "Biology", "Irrigation", "Soil Microbiology", "Triticum", "2. Zero hunger", "Soil organic matter", "Soil Fertility", "Physicochemical factors", "Ecology", "Bacteria", "Microbiota", "Marine Microbial Diversity and Biogeography", "Water", "Life Sciences", "04 agricultural and veterinary sciences", "15. Life on land", "Nitrification", "Agronomy", "6. Clean water", "Chemistry", "Human fertilization", "13. Climate action", "Fertilization", "FOS: Biological sciences", "Environmental Science", "Physical Sciences", "Rhizosphere", "Bulk soil", "0401 agriculture", " forestry", " and fisheries", "Prokaryotic microorganisms", "Endosphere", "Soil Carbon Dynamics and Nutrient Cycling in Ecosystems", "Nutrient"]}, "links": [{"href": "https://doi.org/10.1016/j.scitotenv.2022.156952"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Science%20of%20The%20Total%20Environment", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1016/j.scitotenv.2022.156952", "name": "item", "description": "10.1016/j.scitotenv.2022.156952", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1016/j.scitotenv.2022.156952"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2022-10-01T00:00:00Z"}}, {"id": "10.1016/j.scitotenv.2024.173631", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-07-27T16:17:15Z", "type": "Journal Article", "created": "2024-05-30", "title": "Light drives nitrogen fixation in tropical montane cloud forests in Costa Rica", "description": "Tropical montane cloud forests are high altitude ecosystems characterized by very high ambient humidity, which favors organisms that depend on the environment for their water status, such as bryophytes and their nitrogen-fixing symbionts. Bryophyte-associated N2 fixation is a major source of new N in several northern environments, but their contributions to the N cycle in other ecosystems is still poorly understood. In this work, we evaluated N2 fixation rates associated with epiphytic bryophytes growing along the stems of pumpwood trees (Cecropia sp.) as well as in surrounding litter and soil from a primary and a secondary cloud forests in the Talamanca Mountain Range, Costa Rica. Nitrogen fixation was significantly higher in substrates from the secondary forest compared to those from the primary forest. Overall, N2 fixation rates associated with epiphytic bryophytes were 57 times those of litter and 270 times what was measured in soil. Further, light intensity was the major factor influencing N2 fixation rates in all substrates. Increased access to light in disturbed cloud forests may therefore favor bryophyte-associated N2 fixation, potentially contributing to the recovery of these ecosystems.", "keywords": ["Costa Rica", "0106 biological sciences", "0301 basic medicine", "Tropical Climate", "Light", "Bryophyta", "Forests", "15. Life on land", "01 natural sciences", "Soil", "03 medical and health sciences", "13. Climate action", "Nitrogen Fixation", "Ecosystem", "Environmental Monitoring"]}, "links": [{"href": "https://doi.org/10.1016/j.scitotenv.2024.173631"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Science%20of%20The%20Total%20Environment", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1016/j.scitotenv.2024.173631", "name": "item", "description": "10.1016/j.scitotenv.2024.173631", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1016/j.scitotenv.2024.173631"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2024-08-01T00:00:00Z"}}, {"id": "10.1016/j.soilbio.2007.08.021", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-07-27T16:17:20Z", "type": "Journal Article", "created": "2007-11-09", "title": "Observed And Modelled Soil Carbon And Nitrogen Changes After Planting A Pinus Radiata Stand Onto Former Pasture", "description": "Abstract After reforesting pasture land, it is often observed that soil carbon stocks decrease. The present work reports findings from a site near Canberra, Australia, where a pine forest (Pinus radiata) was planted onto a former unimproved pasture site. We report a number of detailed observations seeking to understand the basis of the decline in soil C stocks. This is supported by simulations using the whole-ecosystem carbon and nitrogen cycling model CenW 3.1. The model indicated that over the first 18 years after forest establishment, the site lost about 5.5\u00a0t\u00a0C\u00a0ha\u22121 and 588\u00a0kgN\u00a0ha\u22121 from the soil. The C:N ratio of soil organic matter did not change in a systematic manner over the observational period. Carbon and nitrogen stocks contained in the biomass of the 18-year old pine stand exceeded that of the pasture by 88\u00a0t\u00a0C\u00a0ha\u22121 and 393\u00a0kgN\u00a0ha\u22121. An additional 6.1\u00a0t\u00a0C\u00a0ha\u22121 and 110\u00a0kgN\u00a0ha\u22121 accumulated in above-ground litter. These changes, together with the vertical distribution of carbon and nitrogen in the soil, agreed well with the observation at the site. It was assumed that over 18 years, there was also a loss of 86\u00a0kgN\u00a0ha\u22121 from the ecosystem because of normal gaseous losses during nitrogen turn-over and a small amount of nitrogen leaching. Those losses could not be replenished in the pine system without symbiotic biological nitrogen fixation, and there were no fertiliser additions. A simple mass balance approach indicated that the amount of nitrogen accumulating in plant biomass and the litter layer plus the assumed nitrogen loss from the site matched the amount of nitrogen lost from the soil organic nitrogen pool. This reduction in soil nitrogen, together with an unchanged C:N ratio, provided a simple and internally consistent explanation for the observed reduction of soil carbon after reforestation. It supports the general notion that trends in soil carbon upon land-use change can often be controlled by the possible fates of available soil nitrogen.", "keywords": ["550", "Nitrogen", "CenW", "Reforesting pasture lands", "910", "Carbon inorganic compounds", "01 natural sciences", "Ecosystems", "Nitrogen compounds", "C:N ratio", "Nitrogen fixation", "Pasture", "Biomass", "Reforestation", "0105 earth and related environmental sciences", "Keywords: Biological materials", "Pinus radiata", "Nitrogen cycling models", "modeling", "04 agricultural and veterinary sciences", "15. Life on land", "carbon sequestration", "Soil carbon", "Pine", "coniferous tree", "Pine forest", "Soils", "0401 agriculture", " forestry", " and fisheries", "Model"], "contacts": [{"organization": "Roger M. Gifford, LanBin Guo, Miko U. F. Kirschbaum, Miko U. F. Kirschbaum,", "roles": ["creator"]}]}, "links": [{"href": "https://openresearch-repository.anu.edu.au/bitstream/1885/61078/5/Kirschbaum_Observed_and_modelled_soil_carbon.pdf.jpg"}, {"href": "https://openresearch-repository.anu.edu.au/bitstream/1885/61078/7/01_Kirschbaum_Observed_and_modelled_soil_2008.pdf.jpg"}, {"href": "https://doi.org/10.1016/j.soilbio.2007.08.021"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Soil%20Biology%20and%20Biochemistry", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1016/j.soilbio.2007.08.021", "name": "item", "description": "10.1016/j.soilbio.2007.08.021", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1016/j.soilbio.2007.08.021"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2008-01-01T00:00:00Z"}}, {"id": "10.1016/j.xplc.2020.100104", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-07-27T16:17:50Z", "type": "Journal Article", "created": "2020-08-21", "title": "No Home without Hormones: How Plant Hormones Control Legume Nodule Organogenesis", "description": "The establishment of symbiotic nitrogen fixation requires the coordination of both nodule development and infection events. Despite the evolution of a variety of anatomical structures, nodule organs serve\u00a0a common purpose in establishing a localized area that facilitates efficient nitrogen fixation. As in all plant developmental processes, the establishment of a new nodule organ is regulated by plant hormones. During nodule initiation, regulation of plant hormone signaling is one of the major targets of symbiotic signaling. We review the role of major developmental hormones in the initiation of the nodule organ and argue that the manipulation of plant hormones is a key requirement for engineering nitrogen fixation in non-legumes as the basis for improved food security and sustainability.", "keywords": ["0301 basic medicine", "2. Zero hunger", "0303 health sciences", "Cytokinins", "hormones", "nodule", "Fabaceae", "legume", "Review Article", "Ethylenes", "Plant Root Nodulation", "symbiosis", "Gibberellins", "03 medical and health sciences", "Plant Growth Regulators", "nitrogen fixation", "Nitrogen Fixation", "Symbiosis"]}, "links": [{"href": "https://doi.org/10.1016/j.xplc.2020.100104"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Plant%20Communications", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1016/j.xplc.2020.100104", "name": "item", "description": "10.1016/j.xplc.2020.100104", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1016/j.xplc.2020.100104"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2020-09-01T00:00:00Z"}}, {"id": "10.1017/wsc.2018.4", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-07-27T16:17:56Z", "type": "Journal Article", "created": "2018-04-04", "title": "Assessment Of Management Options On Striga Infestation And Maize Grain Yield In Kenya", "description": "Abstract

The parasitic purple witchweed [Striga hermonthica(Del.) Benth.] is a serious constraint to maize production in sub-Saharan Africa, especially in poor soils. VariousStrigaspp. control measures have been developed, but these have not been assessed in an integrated system. This study was conducted to evaluate a set of promising technologies forS. hermonthicamanagement in western Kenya. We evaluated three maize genotypes either intercropped with peanut (Arachis hypogaeaL.), soybean [Glycine max(L.) Merr.], or silverleaf desmodium [Desmodium uncinatum(Jacq.) DC] or as a sole crop at two locations under artificialS. hermonthicainfestation and at three locations under naturalS. hermonthicainfestation between 2011 and 2013. Combined ANOVA showed significant (P<0.05) cropping system and cropping system by environment interactions for most traits measured. Grain yield was highest for maize grown in soybean rotation (3,672 kg ha\uffe2\uff88\uff921) under artificial infestation and inD. uncinatumand peanut cropping systems (3,203 kg ha\uffe2\uff88\uff921and 3,193 kg ha\uffe2\uff88\uff921) under natural infestation. Grain yield was highest for theStrigaspp.-resistant hybrid under both methods of infestation. A lower number of emergedS. hermonthicaplants per square meter were recorded at 10 and 12 wk after planting on maize grown underD. uncinatumin the artificialS. hermonthicainfestation. A combination of herbicide-resistant maize varieties intercropped with legumes was a more effective method forS. hermonthicacontrol than individual-component technologies. Herbicide-resistant andStrigaspp.-resistant maize integrated with legumes would help reduce theStrigaspp. seedbank in the soil. Farmers should be encouraged to adopt an integrated approach to controlStrigaspp. for better maize yields.

", "keywords": ["0106 biological sciences", "striga infestation", "legumes", "Infestation", "Plant Science", "Striga", "maize", "01 natural sciences", "Article", "Agricultural and Biological Sciences", "Symbiotic Nitrogen Fixation in Legumes", "peanuts", "Biology", "Sowing", "Sorghum", "Taxonomy", "2. Zero hunger", "Crop Diversity", "Life Sciences", "cropping systems", "Biodiversity", "04 agricultural and veterinary sciences", "Strigolactone Signaling in Plant Interactions", "15. Life on land", "yield", "Agronomy", "soybeans", "Striga hermonthica", "0401 agriculture", " forestry", " and fisheries", "Intercropping in Agricultural Systems", "varieities", "intercropping", "Agronomy and Crop Science"]}, "links": [{"href": "https://doi.org/10.1017/wsc.2018.4"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Weed%20Science", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1017/wsc.2018.4", "name": "item", "description": "10.1017/wsc.2018.4", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1017/wsc.2018.4"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2018-04-04T00:00:00Z"}}, {"id": "10.1023/a:1009783625188", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-07-27T16:18:05Z", "type": "Journal Article", "created": "2002-12-22", "description": "Short-term studies of tree growth at elevated CO2 suggest that forest productivity may increase as atmospheric CO2 concentrations rise, although low soil N availability may limit the magnitude of this response. There have been few studies of growth and N2 fixation by symbiotic N 2-fixing woody species under elevated CO 2 and the N inputs these plants could provide to forest ecosystems in the future. We investigated the effect of twice ambient CO 2 on growth, tissue N accretion, and N2 fixation of nodulatedAlnus glutinosa (L.) Gaertn. grown under low soil N conditions for 160 d. Root, nodule, stem, and leaf dry weight (DW) and N accretion increased significantly in response to elevated CO2. Whole-plant biomass and N accretion increased 54% and 40%, respectively. Delta- 15 Na nalysis of leaf tissue indicated that plants from both treatments derived similar proportions of their total N from symbiotic fixation suggesting that elevated CO 2 grown plants fixed approximately 40% more N than did ambient CO 2 grown plants. Leaves from both CO2 treatments showed similar relative declines in leaf N content prior to autumnal leaf abscission, but total N in leaf litter increased 24% in elevated compared to ambient CO2 grown plants. These results suggest that with rising atmospheric CO2 N2-fixing woody species will accumulate greater amounts of biomass N through N2 fixation and may enhance soil N levels by increased litter N inputs.", "keywords": ["Delta 15 N Analysis", "0106 biological sciences", "Nitrogen Fixation", "Science", "Plant Sciences", "Ecology and Evolutionary Biology", "Life Sciences", "Carbon Dioxide Enrichment", "Root Nodules", "Black Alder", "15. Life on land", "01 natural sciences"], "contacts": [{"organization": "Christoph S. Vogel, Christoph S. Vogel, Richard B. Thomas, Peter S. Curtis, Peter S. Curtis,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.1023/a:1009783625188"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Plant%20Ecology", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1023/a:1009783625188", "name": "item", "description": "10.1023/a:1009783625188", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1023/a:1009783625188"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "1997-05-01T00:00:00Z"}}, {"id": "10.1038/nature01051", "type": "Feature", "geometry": null, "properties": {"license": "unspecified", "updated": "2026-07-27T16:18:18Z", "type": "Journal Article", "created": "2002-10-30", "title": "Quantifying Nitrogen-Fixation In Feather Moss Carpets Of Boreal Forests", "description": "Biological nitrogen (N) fixation is the primary source of N within natural ecosystems, yet the origin of boreal forest N has remained elusive. The boreal forests of Eurasia and North America lack any significant, widespread symbiotic N-fixing plants. With the exception of scattered stands of alder in early primary successional forests, N-fixation in boreal forests is considered to be extremely limited. Nitrogen-fixation in northern European boreal forests has been estimated at only 0.5 kg N ha(-1) yr(-1); however, organic N is accumulated in these ecosystems at a rate of 3 kg N ha(-1) yr(-1) (ref. 8). Our limited understanding of the origin of boreal N is unacceptable given the extent of the boreal forest region, but predictable given our imperfect knowledge of N-fixation. Herein we report on a N-fixing symbiosis between a cyanobacterium (Nostoc sp.) and the ubiquitous feather moss, Pleurozium schreberi (Bird) Mitt. that alone fixes between 1.5 and 2.0 kg N ha(-1) yr(-1) in mid- to late-successional forests of northern Scandinavia and Finland. Previous efforts have probably underestimated N-fixation potential in boreal forests.", "keywords": ["Sweden", "0106 biological sciences", "Acetylene", "Norway", "04 agricultural and veterinary sciences", "15. Life on land", "Cyanobacteria", "01 natural sciences", "Bryopsida", "Trees", "Plant Leaves", "Kinetics", "Nitrogen Fixation", "0401 agriculture", " forestry", " and fisheries", "Symbiosis", "Finland"]}, "links": [{"href": "https://doi.org/10.1038/nature01051"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Nature", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1038/nature01051", "name": "item", "description": "10.1038/nature01051", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1038/nature01051"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2002-10-31T00:00:00Z"}}, {"id": "10.1038/s41467-019-14197-9", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-27T16:18:21Z", "type": "Journal Article", "created": "2020-01-24", "title": "High-quality genome sequence of white lupin provides insight into soil exploration and seed quality", "description": "Abstract

White lupin (Lupinus albus L.) is an annual crop cultivated for its protein-rich seeds. It is adapted to poor soils due to the production of cluster roots, which are made of dozens of determinate lateral roots that drastically improve soil exploration and nutrient acquisition (mostly phosphate). Using long-read sequencing technologies, we provide a high-quality genome sequence of a cultivated accession of white lupin (2n\uffe2\uff80\uff89=\uffe2\uff80\uff8950, 451\uffe2\uff80\uff89Mb), as well as de novo assemblies of a landrace and a wild relative. We describe a modern accession displaying increased soil exploration capacity through early establishment of lateral and cluster roots. We also show how seed quality may have been impacted by domestication in term of protein profiles and alkaloid content. The availability of a high-quality genome assembly together with companion genomic and transcriptomic resources will enable the development of modern breeding strategies to increase and stabilize white lupin yield.

", "keywords": ["Repetitive Sequences", " Nucleic Acid/genetics", "0301 basic medicine", "[SDV]Life Sciences [q-bio]", "Plant Roots/genetics", "Gene Dosage", "Plant Science", "Crop", "Alkaloids/chemistry", "Plant Roots", "Gene", "Repetitive Sequences", "630", "Agricultural and Biological Sciences", "Domestication", "Soil", "Models", "Symbiotic Nitrogen Fixation in Legumes", "Gene Duplication", "[SDV.BV] Life Sciences [q-bio]/Vegetal Biology", "http://aims.fao.org/aos/agrovoc/c_3224", "Plant Proteins/metabolism", "Plant Proteins", "2. Zero hunger", "0303 health sciences", "Genome", "Q", "http://aims.fao.org/aos/agrovoc/c_27583", "Life Sciences", "Transcriptome/genetics", "http://aims.fao.org/aos/agrovoc/c_92382", "Polymorphism", " Single Nucleotide/genetics", "Lupinus", "[SDV] Life Sciences [q-bio]", "Protein Crop", "Seeds", "http://aims.fao.org/aos/agrovoc/c_5956", "White (mutation)", "Single Nucleotide/genetics", "Sequence Analysis", "Genome", " Plant", "expression des g\u00e8nes", "http://aims.fao.org/aos/agrovoc/c_4464", "Synteny/genetics", "Evolution", "Lupin Seeds", "Science", "Centromere", "Lupinus/genetics", "Polymorphism", " Single Nucleotide", "Article", "g\u00e9nomique", "Evolution", " Molecular", "Evolution and Nutritional Properties of Lupin Seeds", "physiologie v\u00e9g\u00e9tale", "03 medical and health sciences", "Alkaloids", "Genetic", "Nucleic Acid/genetics", "Seeds/physiology", "Centromere/genetics", "Genetics", "[SDV.BV]Life Sciences [q-bio]/Vegetal Biology", "Polymorphism", "Biology", "Ecology", " Evolution", " Behavior and Systematics", "Repetitive Sequences", " Nucleic Acid", "Sequence assembly", "http://aims.fao.org/aos/agrovoc/c_25189", "Ecotype", "Models", " Genetic", "g\u00e9nome", "Botany", "Molecular", "Genetic Variation", "Molecular Sequence Annotation", "Plant", "DNA", "Sequence Analysis", " DNA", "s\u00e9quence nucl\u00e9otidique", "15. Life on land", "http://aims.fao.org/aos/agrovoc/c_27527", "Agronomy", "Plant Leaves", "Evolution and Ecology of Endophyte-Grass Symbiosis", "Lupinus albus", "FOS: Biological sciences", "Genomic Structural Variation", "Plant Leaves/metabolism", "Gene expression", "Transcriptome", "am\u00e9lioration des plantes"]}, "links": [{"href": "https://www.nature.com/articles/s41467-019-14197-9.pdf"}, {"href": "https://doi.org/10.1038/s41467-019-14197-9"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Nature%20Communications", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1038/s41467-019-14197-9", "name": "item", "description": "10.1038/s41467-019-14197-9", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1038/s41467-019-14197-9"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2020-01-24T00:00:00Z"}}, {"id": "10.1038/s41586-024-07607-6", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-27T16:18:24Z", "type": "Journal Article", "created": "2024-06-26", "title": "Zinc mediates control of nitrogen fixation via transcription factor filamentation", "description": "Abstract

Plants adapt to fluctuating environmental conditions by adjusting their metabolism and gene expression to maintain fitness1. In legumes, nitrogen homeostasis is maintained by balancing nitrogen acquired from soil resources with nitrogen fixation by symbiotic bacteria in root nodules2\uffe2\uff80\uff938. Here we show that zinc, an essential plant micronutrient, acts as an intracellular second messenger that connects environmental changes to transcription factor control of metabolic activity in root nodules. We identify a transcriptional regulator, FIXATION UNDER NITRATE (FUN), which acts as a sensor, with zinc controlling the transition between an inactive filamentous megastructure and an active transcriptional regulator. Lower zinc concentrations in the nodule, which we show occur in response to higher levels of soil nitrate, dissociates the filament and activates FUN. FUN then directly targets multiple pathways to initiate breakdown of the nodule. The zinc-dependent filamentation mechanism thus establishes a concentration readout to adapt nodule function to the environmental nitrogen conditions. In a wider perspective, these results have implications for understanding the roles of metal ions in integration of environmental signals with plant development and optimizing delivery of fixed nitrogen in legume crops.The rhizobiota, particularly nitrogen-fixing bacteria, play a crucial role in plant functioning by providing essential nutrients and defense against pathogens. This study investigated the diversity of nitrogen-fixing bacteria in a relatively understudied habitat: technosoils developed from industrial soda production. To analyze the bacterial diversity in the rhizosphere soils of wheat (Triticum aestivum L.) and aster (Tripolium pannonicum Jacq.), regions of the nifH gene were amplified and sequenced from the resident bacterial communities. A polyvinylidene fluoride (PVDF) membrane was employed for metagenomic DNA extraction, enhancing the detection of nitrogen-fixing bacteria. Prior to standard DNA extraction, an enrichment step was conducted in nitrogen-free JMV medium at 26\uffc2\uffa0\uffc2\uffb0C for 24\uffc2\uffa0h, with a modification that replaced soil with the PVDF membrane. This approach enabled a more comprehensive analysis of the rhizosphere bacterial community, revealing that unique amplicon sequence variants (ASVs) in aster and wheat membrane samples accounted for a notable proportion of all ASVs in the dataset (8.5% and 23%, respectively) that were not captured using the standard method. Additionally, our findings demonstrated higher alpha diversity of nitrogen-fixing bacteria in the wheat rhizosphere compared to the aster rhizosphere. In wheat, the dominant genus was Insolitispirillum (38.80%), followed by unclassified genera within Gammaproteobacteria (9.76%) and Rhodospirillaceae (4.74%). In contrast, the aster rhizosphere was predominantly occupied by Azotobacter (95.69%).In the present study the effect of elevated CO2 on growth and nitrogen fixation of seven Australian Acacia species was investigated. Two species from semi\uffe2\uff80\uff90arid environments in central Australia (Acacia aneura and A. tetragonophylla) and five species from temperate south\uffe2\uff80\uff90eastern Australia (Acacia irrorata, A. mearnsii, A. dealbata, A. implexa and A. melanoxylon) were grown for up to 148\uffe2\uff80\uff83d in controlled greenhouse conditions at either ambient (350\uffe2\uff80\uff83\uffc2\uffb5mol\uffe2\uff80\uff83mol\uffe2\uff88\uff921) or elevated (700\uffe2\uff80\uff83\uffc2\uffb5mol\uffe2\uff80\uff83mol\uffe2\uff88\uff921) CO2 concentrations. After establishment of nodules, the plants were completely dependent on symbiotic nitrogen fixation. Six out of seven species had greater relative growth rates and lower whole plant nitrogen concentrations under elevated versus normal CO2. Enhanced growth resulted in an increase in the amount of nitrogen fixed symbiotically for five of the species. In general, this was the consequence of lower whole\uffe2\uff80\uff90plant nitrogen concentrations, which equate to a larger plant and greater nodule mass for a given amount of nitrogen. Since the average amount of nitrogen fixed per unit nodule mass was unaltered by atmospheric CO2, more nitrogen could be fixed for a given amount of plant nitrogen. For three of the species, elevated CO2 increased the rate of nitrogen fixation per unit nodule mass and time, but this was completely offset by a reduction in nodule mass per unit plant mass.

", "keywords": ["0106 biological sciences", "0301 basic medicine", "2. Zero hunger", "Acacia mearnsii", "Elevated atmospheric CO2", "Aneura Acacia", "Acacia", "growth response", "15. Life on land", "01 natural sciences", "Acacia dealbata", "Relative growth rate", "03 medical and health sciences", "nitrogen fixation", "Acacia aneura", "Nitrogenase", "Keywords: carbon dioxide enrichment", "Acacia melanoxylon"]}, "links": [{"href": "https://doi.org/10.1046/j.1365-3040.2002.00831.x"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Plant%2C%20Cell%20%26amp%3B%20Environment", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1046/j.1365-3040.2002.00831.x", "name": "item", "description": "10.1046/j.1365-3040.2002.00831.x", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1046/j.1365-3040.2002.00831.x"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2002-03-21T00:00:00Z"}}, {"id": "10.1073/pnas.0509038103", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-07-27T16:18:45Z", "type": "Journal Article", "created": "2006-04-14", "title": "Element interactions limit soil carbon storage", "description": "

Rising levels of atmospheric CO 2 are thought to increase C sinks in terrestrial ecosystems. The potential of these sinks to mitigate CO 2 emissions, however, may be constrained by nutrients. By using metaanalysis, we found that elevated CO 2 only causes accumulation of soil C when N is added at rates well above typical atmospheric N inputs. Similarly, elevated CO 2 only enhances N 2 fixation, the major natural process providing soil N input, when other nutrients (e.g., phosphorus, molybdenum, and potassium) are added. Hence, soil C sequestration under elevated CO 2 is constrained both directly by N availability and indirectly by nutrients needed to support N 2 fixation.

", "keywords": ["Greenhouse Effect", "Nitrogen", "cycles", "fine roots", "Plant Development", "01 natural sciences", "forest", "Soil", "Nitrogen Fixation", "elevated atmospheric co2", "Ecosystem", "0105 earth and related environmental sciences", "model", "biological nitrogen-fixation", "04 agricultural and veterinary sciences", "Carbon Dioxide", "Plants", "15. Life on land", "Carbon", "6. Clean water", "13. Climate action", "climate-change", "0401 agriculture", " forestry", " and fisheries", "grassland", "ecosystem responses", "metaanalysis"]}, "links": [{"href": "https://doi.org/10.1073/pnas.0509038103"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Proceedings%20of%20the%20National%20Academy%20of%20Sciences", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1073/pnas.0509038103", "name": "item", "description": "10.1073/pnas.0509038103", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1073/pnas.0509038103"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2006-04-25T00:00:00Z"}}, {"id": "10.1080/08903060050136432", "type": "Feature", "geometry": null, "properties": {"license": "unspecified", "updated": "2026-07-27T16:18:56Z", "type": "Journal Article", "created": "2002-07-26", "title": "Alley Cropping Of Maize And Gliricidia Sepium In The Sudanese Sahel Region: Some Technical Feasibility Aspects", "description": "An association in an alley cropping experiment of a short-term maize variety and a tree legume (#Gliricidia sepium#) adapted to the Sudanese Sahel region was studied from the point of view of the nitrogen balance and plot yields. Isotopic labelling applied in the field enabled the contribution to maize nitrogen nutrition from different nitrogen sources (fertilizer, prunings, and soil) to be quantified. For equal cultivated areas, alley cropping provides a maize yield greater than that of maize grown in pure stand without nitrogen fertilizer. However this yield is only 40% of that obtained in pure stands with fertilizer nitrogen. Alley cropping gives a very favourable Land Equivalent Ratio (LER) of 0.90 and 1.58 compared with N-fertilized and non-N-fertilized plots, respectively. These LERs demonstrate the increased biological efficiency of the cultivated soil in an agroforestry system. The percentage of the total nitrogen in the maize coming from prunings (Nfdp) varies between 30 and 35% and the true coefficient of nitrogen utilization of the prunings (TCUp) varies from 15-25%. In the environment of central Senegal, the percentage of total nitrogen of #G. sepium# coming from N2 fixation is quite low (Ndffix = 25%), and consequently, in the maize, the nitrogen coming from N2 fixation (Ndffix) is only 8%. It is therefore necessary to improve the efficiency of nitrogen fixation of #G. sepium# in this zone to assure the sustainability of the agroforestry system. (Resume d'auteur)", "keywords": ["Fixation de l'azote", "engrais organique", "Nitrogen", "F08 - Syst\u00e8mes et modes de culture", "rendement des cultures", "http://aims.fao.org/aos/agrovoc/c_5192", "Soil fertility", "Zea mays", "Gliricidia sepium", "fertilisation", "http://aims.fao.org/aos/agrovoc/c_16379", "http://aims.fao.org/aos/agrovoc/c_10176", "http://aims.fao.org/aos/agrovoc/c_4592", "Nitrogen fixation", "F01 - Culture des plantes", "Agroforestry", "http://aims.fao.org/aos/agrovoc/c_6970", "Ecosystem", "http://aims.fao.org/aos/agrovoc/c_10795", "azote", "agroforesterie", "2. Zero hunger", "technique des traceurs", "engrais azot\u00e9", "nutrition des plantes", "Agriculture", "04 agricultural and veterinary sciences", "15. Life on land", "http://aims.fao.org/aos/agrovoc/c_207", "Utilization", "http://aims.fao.org/aos/agrovoc/c_8504", "http://aims.fao.org/aos/agrovoc/c_7835", "Fertilization", "http://aims.fao.org/aos/agrovoc/c_3910", "0401 agriculture", " forestry", " and fisheries", "culture intercalaire", "http://aims.fao.org/aos/agrovoc/c_5195", "http://aims.fao.org/aos/agrovoc/c_5196", "http://aims.fao.org/aos/agrovoc/c_3278", "F04 - Fertilisation"], "contacts": [{"organization": "Ndiaye, Mamadou, Ganry, Francis, Oliver, Robert,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.1080/08903060050136432"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Arid%20Soil%20Research%20and%20Rehabilitation", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1080/08903060050136432", "name": "item", "description": "10.1080/08903060050136432", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1080/08903060050136432"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2000-01-01T00:00:00Z"}}, {"id": "10.1093/jxb/erq249", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-27T16:19:05Z", "type": "Journal Article", "created": "2010-08-27", "title": "Plant Physiology And Proteomics Reveals The Leaf Response To Drought In Alfalfa (Medicago Sativa L.)", "description": "Despite its relevance, protein regulation, metabolic adjustment, and the physiological status of plants under drought is not well understood in relation to the role of nitrogen fixation in nodules. In this study, nodulated alfalfa plants were exposed to drought conditions. The study determined the physiological, metabolic, and proteomic processes involved in photosynthetic inhibition in relation to the decrease in nitrogenase (N(ase)) activity. The deleterious effect of drought on alfalfa performance was targeted towards photosynthesis and N(ase) activity. At the leaf level, photosynthetic inhibition was mainly caused by the inhibition of Rubisco. The proteomic profile and physiological measurements revealed that the reduced carboxylation capacity of droughted plants was related to limitations in Rubisco protein content, activation state, and RuBP regeneration. Drought also decreased amino acid content such as asparagine, and glutamic acid, and Rubisco protein content indicating that N availability limitations were caused by N(ase) activity inhibition. In this context, drought induced the decrease in Rubisco binding protein content at the leaf level and proteases were up-regulated so as to degrade Rubisco protein. This degradation enabled the reallocation of the Rubisco-derived N to the synthesis of amino acids with osmoregulant capacity. Rubisco degradation under drought conditions was induced so as to remobilize Rubisco-derived N to compensate for the decrease in N associated with N(ase) inhibition. Metabolic analyses showed that droughted plants increased amino acid (proline, a major compound involved in osmotic regulation) and soluble sugar (D-pinitol) levels to contribute towards the decrease in osmotic potential (\u03a8(s)). At the nodule level, drought had an inhibitory effect on N(ase) activity. This decrease in N(ase) activity was not induced by substrate shortage, as reflected by an increase in total soluble sugars (TSS) in the nodules. Proline accumulation in the nodule could also be associated with an osmoregulatory response to drought and might function as a protective agent against ROS. In droughted nodules, the decrease in N(2) fixation was caused by an increase in oxygen resistance that was induced in the nodule. This was a mechanism to avoid oxidative damage associated with reduced respiration activity and the consequent increase in oxygen content. This study highlighted that even though drought had a direct effect on leaves, the deleterious effects of drought on nodules also conditioned leaf responsiveness.", "keywords": ["Proteomics", "0301 basic medicine", "570", "Rubisco", "Proteome", "[SDV]Life Sciences [q-bio]", "proteome", "N-2 FIXATION RESPONSE", "drought", "N2 fixation", "03 medical and health sciences", "XANTHOPHYLL CYCLE", "N-2 fixation", "2-CYSTEINE PEROXIREDOXIN", "Nitrogenase", "oxidative stress", "AMINO-ACIDS", "Photosynthesis", "climate", "agriculture", "Plant Proteins", "580", "N remobilization", "2. Zero hunger", "0303 health sciences", "photosynthesis", "PINITOL ACCUMULATION", "Drought", "RIBULOSE-1", "5-BISPHOSPHATE CARBOXYLASE-OXYGENASE", "Water", "BRASSICA-NAPUS", "N(O)-TERT-BUTYLDIMETHYLSILYL DERIVATIVES", "15. Life on land", "Research Papers", "6. Clean water", "Droughts", "[SDV] Life Sciences [q-bio]", "Plant Leaves", "nitrogen fixation", "Oxidative stress", "rubisco", "NITROGEN-FIXATION", "WATER-WATER CYCLE", "Medicago sativa"]}, "links": [{"href": "https://doi.org/10.1093/jxb/erq249"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Journal%20of%20Experimental%20Botany", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1093/jxb/erq249", "name": "item", "description": "10.1093/jxb/erq249", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1093/jxb/erq249"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2010-08-25T00:00:00Z"}}, {"id": "10.1093/treephys/23.15.1051", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-07-27T16:19:07Z", "type": "Journal Article", "created": "2012-01-20", "title": "Effects Of Elevated Carbon Dioxide Concentration On Growth And Nitrogen Fixation In Alnus Glutinosa In A Long-Term Field Experiment", "description": "Nitrogen-fixing plant species may respond more positively to elevated atmospheric carbon dioxide concentrations ([CO2]) than other species because of their ability to maintain a high internal nutrient supply. A key factor in the growth response of trees to elevated [CO2] is the availability of nitrogen, although how elevated [CO2] influences the rate of N2-fixation of nodulated trees growing under field conditions is unclear. To elucidate this relationship, we measured total biomass, relative growth rate, net assimilation rate (NAR), leaf area and net photosynthetic rate of N2-fixing Alnus glutinosa (L.) Gaertn. (common alder) trees grown for 3 years in open-top chambers in the presence of either ambient or elevated atmospheric [CO2] and two soil N regimes: full nutrient solution or no fertilizer. Nitrogen fixation by Frankia spp. in the root nodules of unfertilized trees was assessed by the acetylene reduction method. We hypothesized that unfertilized trees would show similar positive growth and physiological responses to elevated [CO2] as the fertilized trees. Growth in elevated [CO2] stimulated (relative) net photosynthesis and (absolute) total biomass accumulation. Relative total biomass increased, and leaf nitrogen remained stable, only during the first year of the experiment. Toward the end of the experiment, signs of photosynthetic acclimation occurred, i.e., down-regulation of the photosynthetic apparatus. Relative growth rate was not significantly affected by elevated [CO2] because although NAR was increased, the effect on relative growth rate was negated by a reduction in leaf area ratio. Neither leaf area nor leaf P concentration was affected by growth in elevated [CO2]. Nodule mass increased on roots of unfertilized trees exposed to elevated [CO2] compared with fertilized trees exposed to ambient [CO2]. There was also a biologically significant, although not statistically significant, stimulation of nitrogenase activity in nodules exposed to elevated [CO2]. Root nodules of trees exposed to elevated [CO2] were smaller and more evenly spaced than root nodules of trees exposed to ambient [CO2]. The lack of an interaction between nutrient and [CO2] effects on growth, biomass and photosynthesis indicates that the unfertilized trees maintained similar CO2-induced growth and photosynthetic enhancements as the fertilized trees. This implies that alder trees growing in natural conditions, which are often limited by soil N availability, should nevertheless benefit from increasing atmospheric [CO2].", "keywords": ["Plant Leaves", "0106 biological sciences", "13. Climate action", "Nitrogen Fixation", "0401 agriculture", " forestry", " and fisheries", "04 agricultural and veterinary sciences", "15. Life on land", "Carbon Dioxide", "Photosynthesis", "Alnus", "01 natural sciences", "Trees"]}, "links": [{"href": "https://doi.org/10.1093/treephys/23.15.1051"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Tree%20Physiology", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1093/treephys/23.15.1051", "name": "item", "description": "10.1093/treephys/23.15.1051", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1093/treephys/23.15.1051"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2003-10-01T00:00:00Z"}}, {"id": "10.1093/treephys/24.3.323", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-07-27T16:19:07Z", "type": "Journal Article", "created": "2012-01-20", "title": "Effects Of Elevated Carbon Dioxide Concentration On Growth And N-2 Fixation Of Young Robinia Pseudoacacia", "description": "Effects of elevated CO2 concentration ([CO2]) on carbon (C) and nitrogen (N) uptake and N source partitioning (N2 fixation versus mineral soil N uptake) of 1-year-old Robinia pseudoacacia were determined in a dual 13C and 15N continuous labeling experiment. Seedlings were grown for 16 weeks in ambient (350 ppm) or elevated [CO2] (700 ppm) with 15NH4 15NO3 as the only mineral nitrogen source. Elevated [CO2] increased the fraction of new C in total C, but it did not alter C partitioning among plant compartments. Elevated [CO2] also increased the fraction of new N in total N and this was coupled with a shift in N source partitioning toward N2 fixation. Soil N uptake was unaffected by elevated [CO2], whereas N2 fixation was markedly increased by the elevated [CO2] treatment, mainly because of increased specific fixation (mg N mg(-1) nodule). As a result of increased N2 fixation, the C/N ratio of tree biomass tended to decrease in the elevated [CO2] treatment. Partitioning of N uptake among plant compartments was unaffected by elevated [CO2]. Total dry mass of root nodules doubled in response to elevated [CO2], but this effect was not significant because of the great variability of root nodule formation. Our results show that, in the N2-fixing R. pseudoacacia, increased C uptake in response to increased [CO2] is matched by increased N2 fixation, indicating that enhanced growth in elevated [CO2] might not be restricted by N limitations.", "keywords": ["0106 biological sciences", "Seedlings", "Nitrogen Fixation", "Robinia", "0401 agriculture", " forestry", " and fisheries", "04 agricultural and veterinary sciences", "Carbon Dioxide", "15. Life on land", "01 natural sciences", "Trees"], "contacts": [{"organization": "Feng, Zhe, Dyckmans, Jens, Flessa, Heiner,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.1093/treephys/24.3.323"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Tree%20Physiology", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1093/treephys/24.3.323", "name": "item", "description": "10.1093/treephys/24.3.323", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1093/treephys/24.3.323"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2004-03-01T00:00:00Z"}}, {"id": "10.1093/treephys/tpu116", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-07-27T16:19:08Z", "type": "Journal Article", "created": "2015-01-24", "title": "Dinitrogen Fixation By Legume Shade Trees And Direct Transfer Of Fixed N To Associated Cacao In A Tropical Agroforestry System", "description": "Natural abundance of (15)N (\u03b4\u2009(15)N) was determined in bulk soil, rhizospheric soil and vegetation in an organically managed cacao (Theobroma cacao L.) plantation with Inga edulis Mart. legume trees (inga) as the principal shade for studying the nitrogen (N) cycle in the system. Cacao without contact with legumes in an adjacent plantation was used as the reference for N2 fixation and direct N transfer calculations. Bulk and rhizospheric soils contained 72 and 20%, respectively, of whole- system N. No vegetation effect on \u03b4\u2009(15)N in rhizospheric soil was detected, probably due to the high native soil N pool. Fine roots of the cacaos associated with inga contained \u223c35% of N fixed from the atmosphere (Nf) out of the total N. Leaves of all species had significantly higher \u03b4\u2009(15)N than fine roots. Twenty percent of system Nf was found in cacao suggesting direct N transfer from inga via a common mycelial network of mycorrhizal fungi or recycling of N-rich root exudates of inga. Inga had accumulated 98\u2005kg [Nf] ha(-1) during the 14-year history of the plantation. The conservative estimate of current N2 fixation rate was 41\u2005kg [Nf] ha(-1)\u2005year(-1) based on inga biomass only and 50\u2005kg [Nf] ha(-1)\u2005year(-1) based on inga and associated trees.", "keywords": ["2. Zero hunger", "Cacao", "Tropical Climate", "Nitrogen Isotopes", "Nitrogen", "Plant Exudates", "Fabaceae", "04 agricultural and veterinary sciences", "Forests", "15. Life on land", "Plant Roots", "Trees", "Plant Leaves", "Soil", "Mycorrhizae", "Nitrogen Fixation", "0401 agriculture", " forestry", " and fisheries", "Biomass", "Soil Microbiology"]}, "links": [{"href": "https://doi.org/10.1093/treephys/tpu116"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Tree%20Physiology", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1093/treephys/tpu116", "name": "item", "description": "10.1093/treephys/tpu116", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1093/treephys/tpu116"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2015-01-24T00:00:00Z"}}, {"id": "10.1111/1462-2920.16213", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-07-27T16:19:18Z", "type": "Journal Article", "created": "2022-10-18", "title": "Application of stable\u2010isotope labelling techniques for the detection of active diazotrophs", "description": "Summary

Investigating active participants in the fixation of dinitrogen gas is vital as N is often a limiting factor for primary production. Biological nitrogen fixation is performed by a diverse guild of bacteria and archaea (diazotrophs), which can be free\uffe2\uff80\uff90living or symbionts. Free\uffe2\uff80\uff90living diazotrophs are widely distributed in the environment, yet our knowledge about their identity and ecophysiology is still limited. A major challenge in investigating this guild is inferring activity from genetic data as this process is highly regulated. To address this challenge, we evaluated and improved several 15N\uffe2\uff80\uff90based methods for detecting N2 fixation activity (with a focus on soil samples) and studying active diazotrophs. We compared the acetylene reduction assay and the 15N2 tracer method and demonstrated that the latter is more sensitive in samples with low activity. Additionally, tracing 15N into microbial RNA provides much higher sensitivity compared to bulk soil analysis. Active soil diazotrophs were identified with a 15N\uffe2\uff80\uff90RNA\uffe2\uff80\uff90SIP approach optimized for environmental samples and benchmarked to 15N\uffe2\uff80\uff90DNA\uffe2\uff80\uff90SIP. Lastly, we investigated the feasibility of using SIP\uffe2\uff80\uff90Raman microspectroscopy for detecting 15N\uffe2\uff80\uff90labelled cells. Taken together, these tools allow identifying and investigating active free\uffe2\uff80\uff90living diazotrophs in a highly sensitive manner in diverse environments, from bulk to the single\uffe2\uff80\uff90cell level.Most mosses are colonized by nitrogen (N)\uffe2\uff80\uff90fixing cyanobacteria. This discovery is relatively recent, which can explain the large knowledge gaps the field is now tackling. For instance, while we have a good understanding of the abiotic controls (e.g. nutrient availability, increased temperature), we still do not know much about the biotic controls of N2 fixation in mosses. I propose here that we should endeavour to position moss\uffe2\uff80\uff93cyanobacteria associations along the mutualism\uffe2\uff80\uff93parasitism continuum under varying abiotic conditions (e.g. nutrient availability). This would finally unravel the nature of the relationship between the partners and will be a big leap in our understanding of the evolution of plant\uffe2\uff80\uff93bacteria interactions using moss\uffe2\uff80\uff93cyanobacteria associations as a model system.

Bacteria colonize plant roots and engage in reciprocal interactions with their hosts. However, the contribution of individual taxa or groups of bacteria to plant nutrition and fitness is not well characterized due to a lack of in\uffc2\uffa0situ evidence of bacterial activity.

To address this knowledge gap, we developed an analytical approach that combines the identification and localization of individual bacteria on root surfaces via gold\uffe2\uff80\uff90based in\uffc2\uffa0situ hybridization with correlative NanoSIMS imaging of incorporated stable isotopes, indicative of metabolic activity.

We incubated Kosakonia strain DS\uffe2\uff80\uff901\uffe2\uff80\uff90associated, gnotobiotically grown rice plants with 15N\uffe2\uff80\uff93N2 gas to detect in\uffc2\uffa0situ N2 fixation activity. Bacterial cells along the rhizoplane showed\uffc2\uffa0heterogeneous patterns of 15N enrichment, ranging from the natural isotope abundance levels up to 12.07 at% 15N (average and median of 3.36 and 2.85 at% 15N, respectively, n\uffe2\uff80\uff89=\uffe2\uff80\uff89697 cells).

The presented correlative optical and chemical imaging analysis is applicable to a broad range of studies investigating plant\uffe2\uff80\uff93microbe interactions. For example, it enables verification of the in\uffc2\uffa0situ metabolic activity of host\uffe2\uff80\uff90associated commercialized strains or plant growth\uffe2\uff80\uff90promoting bacteria, thereby disentangling their role in plant nutrition. Such data facilitate the design of plant\uffe2\uff80\uff93microbe combinations for improvement of crop management.

Ombrotrophic peatlands are a recognized global carbon reservoir. Without restoration and peat regrowth, harvested peatlands are dramatically altered, impairing their carbon sink function, with consequences for methane turnover. Previous studies determined the impact of commercial mining on the physicochemical properties of peat and the effects on methane turnover. However, the response of the underlying microbial communities catalyzing methane production and oxidation have so far received little attention. We hypothesize that with the return of Sphagnum spp. postharvest, methane turnover potential and the corresponding microbial communities will converge in a natural and restored peatland. To address our hypothesis, we determined the potential methane production and oxidation rates in natural (as a reference), actively mined, abandoned, and restored peatlands over two consecutive years. In all sites, the methanogenic and methanotrophic population sizes were enumerated using quantitative PCR (qPCR) assays targeting the mcrA and pmoA genes, respectively. Shifts in the community composition were determined using Illumina MiSeq sequencing of the mcrA gene and a pmoA -based terminal restriction fragment length polymorphism (t-RFLP) analysis, complemented by cloning and sequence analysis of the mmoX gene. Peat mining adversely affected methane turnover potential, but the rates recovered in the restored site. The recovery in potential activity was reflected in the methanogenic and methanotrophic abundances. However, the microbial community composition was altered, being more pronounced for the methanotrophs. Overall, we observed a lag between the recovery of the methanogenic/methanotrophic activity and the return of the corresponding microbial communities, suggesting that a longer duration (>15 years) is needed to reverse mining-induced effects on the methane-cycling microbial communities.

IMPORTANCE Ombrotrophic peatlands are a crucial carbon sink, but this environment is also a source of methane, an important greenhouse gas. Methane emission in peatlands is regulated by methane production and oxidation catalyzed by methanogens and methanotrophs, respectively. Methane-cycling microbial communities have been documented in natural peatlands. However, less is known of their response to peat mining and of the recovery of the community after restoration. Mining exerts an adverse impact on potential methane production and oxidation rates and on methanogenic and methanotrophic population abundances. Peat mining also induced a shift in the methane-cycling microbial community composition. Nevertheless, with the return of Sphagnum spp. in the restored site after 15 years, methanogenic and methanotrophic activity and population abundance recovered well. The recovery, however, was not fully reflected in the community composition, suggesting that >15 years are needed to reverse mining-induced effects.

", "keywords": ["0301 basic medicine", "570", "oxidation", "hiili", "ta1172", "Euryarchaeota", "630", "Mining", "Soil", "03 medical and health sciences", "Sphagnum", "Bacterial Proteins", "Nitrogen Fixation", "Sphagnopsida", "14. Life underwater", "ennallistaminen", "turvemaat", "Ecosystem", "Phylogeny", "Soil Microbiology", "0303 health sciences", "nifH", "methane", "Microbiota", "ta1182", "land use", "methanogenesis", "15. Life on land", "Carbon", "kasvihuonekaasup\u00e4\u00e4st\u00f6t", "nitrogen fixation", "13. Climate action", "international", "Wetlands", "Oxygenases", "ta1181", "Methane", "Oxidation-Reduction"]}, "links": [{"href": "https://journals.asm.org/doi/pdf/10.1128/AEM.02218-17"}, {"href": "https://doi.org/10.1128/aem.02218-17"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Applied%20and%20Environmental%20Microbiology", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1128/aem.02218-17", "name": "item", "description": "10.1128/aem.02218-17", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1128/aem.02218-17"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2018-02-01T00:00:00Z"}}, {"id": "10.1128/aem.71.5.2713-2722.2005", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-07-27T16:19:54Z", "type": "Journal Article", "created": "2005-05-03", "title": "Changes In Nitrogen-Fixing And Ammonia-Oxidizing Bacterial Communities In Soil Of A Mixed Conifer Forest After Wildfire", "description": "ABSTRACT

This study was undertaken to examine the effects of forest fire on two important groups of N-cycling bacteria in soil, the nitrogen-fixing and ammonia-oxidizing bacteria. Sequence and terminal restriction fragment length polymorphism (T-RFLP) analysis of nifH and amoA PCR amplicons was performed on DNA samples from unburned, moderately burned, and severely burned soils of a mixed conifer forest. PCR results indicated that the soil biomass and proportion of nitrogen-fixing and ammonia-oxidizing species was less in soil from the fire-impacted sites than from the unburned sites. The number of dominant nifH sequence types was greater in fire-impacted soils, and nifH sequences that were most closely related to those from the spore-forming taxa Clostridium and Paenibacillus were more abundant in the burned soils. In T-RFLP patterns of the ammonia-oxidizing community, terminal restriction fragments (TRFs) representing amoA cluster 1, 2, or 4 Nitrosospira spp. were dominant (80 to 90%) in unburned soils, while TRFs representing amoA cluster 3A Nitrosospira spp. dominated (65 to 95%) in fire-impacted soils. The dominance of amoA cluster 3A Nitrosospira spp. sequence types was positively correlated with soil pH (5.6 to 7.5) and NH 3 -N levels (0.002 to 0.976 ppm), both of which were higher in burned soils. The decreased microbial biomass and shift in nitrogen-fixing and ammonia-oxidizing communities were still evident in fire-impacted soils collected 14 months after the fire.

", "keywords": ["2. Zero hunger", "0301 basic medicine", "0303 health sciences", "Bacteria", "Base Sequence", "Molecular Sequence Data", "15. Life on land", "Polymerase Chain Reaction", "Fires", "Trees", "Soil", "03 medical and health sciences", "Ammonia", "Nitrogen Fixation", "Oxidoreductases", "Oxidation-Reduction", "Polymorphism", " Restriction Fragment Length", "Soil Microbiology"], "contacts": [{"organization": "Chris M. Yeager, Diana E. Northup, Susan M. Barns, Cheryl R. Kuske, Christy C. Grow,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.1128/aem.71.5.2713-2722.2005"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Applied%20and%20Environmental%20Microbiology", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1128/aem.71.5.2713-2722.2005", "name": "item", "description": "10.1128/aem.71.5.2713-2722.2005", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1128/aem.71.5.2713-2722.2005"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2005-05-01T00:00:00Z"}}, {"id": "10.1186/s40168-019-0757-8", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-07-27T16:20:05Z", "type": "Journal Article", "created": "2019-10-31", "title": "Suppressed N fixation and diazotrophs after four decades of fertilization", "description": "Abstract Background

N fixation is one of the most important microbially driven ecosystem processes on Earth, allowing N to enter the soil from the atmosphere, and regulating plant productivity. A question that remains to be answered is whether such a fundamental process would still be that important in an over-fertilized world, as the long-term effects of fertilization on N fixation and associated diazotrophic communities remain to be tested. Here, we used a 35-year fertilization experiment, and investigated the changes in N fixation rates and the diazotrophic community in response to long-term inorganic and organic fertilization.

Results

It was found that N fixation was drastically reduced (dropped by 50%) after almost four decades of fertilization. Our results further indicated that functionality losses were associated with reductions in the relative abundance of keystone and phylogenetically clustered N fixers such as Geobacter spp.

Conclusions

Our work suggests that long-term fertilization might have selected against N fixation and specific groups of N fixers. Our study provides solid evidence that N fixation and certain groups of diazotrophic taxa will be largely suppressed in a more and more fertilized world, with implications for soil biodiversity and ecosystem functions.

", "keywords": ["2. Zero hunger", "0301 basic medicine", "Diazotrophs", "0303 health sciences", "Nitrogen", "Research", "QR100-130", "Agriculture", "Biodiversity", "15. Life on land", "Microbial ecology", "03 medical and health sciences", "13. Climate action", "Nitrogen Fixation", "XXXXXX - Unknown", "Long-term fertilization", "Ecological clusters", "Fertilizers", "Ecosystem", "Phylogeny", "Soil Microbiology", "Nitrogen fixation rates"]}, "links": [{"href": "https://doi.org/10.1186/s40168-019-0757-8"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Microbiome", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1186/s40168-019-0757-8", "name": "item", "description": "10.1186/s40168-019-0757-8", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1186/s40168-019-0757-8"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2019-10-31T00:00:00Z"}}, {"id": "10.1890/08-0127.1", "type": "Feature", "geometry": null, "properties": {"license": "Closed Access", "updated": "2026-07-27T16:20:43Z", "type": "Journal Article", "created": "2010-02-23", "title": "Terrestrial Phosphorus Limitation: Mechanisms, Implications, And Nitrogen-Phosphorus Interactions", "description": "

Nutrient limitation to primary productivity and other biological processes is widespread in terrestrial ecosystems, and nitrogen (N) and phosphorus (P) are the most common limiting elements, both individually and in combination. Mechanisms that drive P limitation, and their interactions with the N cycle, have received less attention than mechanisms causing N limitation. We identify and discuss six mechanisms that could drive P limitation in terrestrial ecosystems. The best known of these is depletion\uffe2\uff80\uff90driven limitation, in which accumulated P losses during long\uffe2\uff80\uff90term soil and ecosystem development contribute to what Walker and Syers termed a \uffe2\uff80\uff9cterminal steady state\uffe2\uff80\uff9d of profound P depletion and limitation. The other mechanisms are soil barriers that prevent access to P; transactional limitation, in which weathering of P\uffe2\uff80\uff90containing minerals does not keep pace with the supply of other resources; low\uffe2\uff80\uff90P parent materials; P sinks; and anthropogenic changes that increase the supply of other resources (often N) relative to P. We distinguish proximate nutrient limitation (which occurs where additions of a nutrient stimulate biological processes, especially productivity) from ultimate nutrient limitation (where additions of a nutrient can transform ecosystems). Of the mechanisms that drive P limitation, we suggest that depletion, soil barriers, and low\uffe2\uff80\uff90P parent material often cause ultimate limitation because they control the ecosystem mass balance of P. Similarly, demand\uffe2\uff80\uff90independent losses and constraints to N fixation can control the ecosystem\uffe2\uff80\uff90level mass balance of N and cause it to be an ultimate limiting nutrient.

", "keywords": ["2. Zero hunger", "0106 biological sciences", "Nitrogen", "13. Climate action", "Climate Change", "Nitrogen Fixation", "0401 agriculture", " forestry", " and fisheries", "Phosphorus", "04 agricultural and veterinary sciences", "15. Life on land", "01 natural sciences", "Ecosystem"]}, "links": [{"href": "https://doi.org/10.1890/08-0127.1"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Ecological%20Applications", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1890/08-0127.1", "name": "item", "description": "10.1890/08-0127.1", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1890/08-0127.1"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2010-01-01T00:00:00Z"}}, {"id": "10.1897/04-036r.1", "type": "Feature", "geometry": null, "properties": {"license": "Closed Access", "updated": "2026-07-27T16:20:45Z", "type": "Journal Article", "created": "2005-03-19", "title": "Toxicity Of Heavy Metals In Soil Assessed With Various Soil Microbial And Plant Growth Assays: As Comparative Study", "description": "Abstract

Elevated metal concentrations in soils can disturb the soil ecosystem; thus, researcherss rive to identify the most sensitive assay for detection of the early signs of toxicity. The purpose of the present study was to compare eight different ecotoxicological endpoints on the same set of metal-contaminated soils that were collected from seven series of soils sampled during field trials. The endpoints are based on three microbial assays (potential nitrification rate [PNR], substrate-induced respiration [SIR], and basal respiration [BR]) and two plant growth tests, one of which included symbiotic N fixation. The overall sensitivity of the endpoints to detect statistically significant adverse effects ranked as follows: PNR &gt; SIR (lag time) &gt; plant yield and N fixation &gt; SIR (respiration after 24 and 48 h) &gt; BR. The lowest adverse effect concentrations were found with the PNR at 7 mg kg\uffe2\uff88\uff921 of Cd and 107 mg kg\uffe2\uff88\uff921 of Zn. The variability of these endpoints among different uncontaminated soils was additionally assessed on 14 soil samples. That variability showed a strong correlation with sensitivity scores, illustrating that metal-sensitive endpoints have a large natural variability. We question the ecological relevance of highly sensitive microbial assays, because they tend to have a large natural variability. The identification of toxicity in the field requires endpoints that are highly sensitive and that do not vary greatly among soils (i.e., robust); however, no such endpoint was found in the present study. The endpoints that combined average sensitivity and robustness were SIR (lag time), clover yield, and N fixation in clover.

", "keywords": ["Hungary", "Sewage", "04 agricultural and veterinary sciences", "15. Life on land", "6. Clean water", "Zinc", "Nitrogen Fixation", "London", "Lolium", "Soil Pollutants", "0401 agriculture", " forestry", " and fisheries", "Trifolium", "France", "Soil Microbiology", "Cadmium"]}, "links": [{"href": "https://doi.org/10.1897/04-036r.1"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Environmental%20Toxicology%20and%20Chemistry", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1897/04-036r.1", "name": "item", "description": "10.1897/04-036r.1", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1897/04-036r.1"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2005-03-01T00:00:00Z"}}, {"id": "10.21203/rs.3.rs-1022519/v1", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-07-27T16:20:48Z", "type": "Journal Article", "created": "2021-11-08", "title": "Too Much of a Good Thing? Inorganic Nitrogen (N) Inhibits Moss-Associated N2 Fixation But Organic N Can Promote It", "description": "Abstract

Moss-associated nitrogen (N2) fixation is one of the main inputs of new N in pristine ecosystems that receive low amounts of atmospheric N deposition. Previous studies have shown that N2 fixation is inhibited by inorganic N (IN) inputs, but if N2 fixation in mosses is similarly affected by organic N (ON) remains unknown. Here, we assessed N2 fixation in two dominant mosses in boreal forests (Pleurozium schreberi and Sphagnum capillifolium) in response to different levels of N, simulating realistic (up to 4 kg N ha\u22121 yr\u22121) and extreme N deposition rates in pristine ecosystems (up to 20 kg N ha\u22121 yr\u22121) of IN (NH4NO3) and ON (alanine and urea). We also assessed if N2 fixation can recover from the N additions. In the realistic scenario, N2 fixation was inhibited by increasing NH4NO3 additions in P. schreberi but not in S. capillifolium, and alanine and urea stimulated N2 fixation in both moss species. In contrast, in the extreme N additions, increasing N inputs inhibited N2 fixation in both moss species and all N forms. Nitrogen fixation was more sensitive to N inputs in P. schreberi than in S. capillifolium and was higher in the recovery phase after the realistic compared to the extreme N additions. These results demonstrate that N2 fixation in mosses is less sensitive to organic than inorganic N inputs and highlight the importance of considering different N forms and species-specific responses when estimating the impact of N inputs on ecosystem functions such as moss-associated N2 fixation.

", "keywords": ["0301 basic medicine", "0303 health sciences", "03 medical and health sciences", "Sphagnum", "Nitrogen fixation", "Nitrogen pollution", "Organic nitrogen", "15. Life on land", "Cyanobacteria", "Feathermosses"]}, "links": [{"href": "https://doi.org/10.21203/rs.3.rs-1022519/v1"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Biogeochemistry", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.21203/rs.3.rs-1022519/v1", "name": "item", "description": "10.21203/rs.3.rs-1022519/v1", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.21203/rs.3.rs-1022519/v1"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2021-11-08T00:00:00Z"}}, {"id": "10.3389/fmicb.2018.00703", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-07-27T16:21:36Z", "type": "Journal Article", "created": "2018-04-30", "title": "Evaluation of Primers Targeting the Diazotroph Functional Gene and Development of NifMAP \u2013 A Bioinformatics Pipeline for Analyzing nifH Amplicon Data", "description": "Diazotrophic microorganisms introduce biologically available nitrogen (N) to the global N cycle through the activity of the nitrogenase enzyme. The genetically conserved dinitrogenase reductase (nifH) gene is phylogenetically distributed across four clusters (I-IV) and is widely used as a marker gene for N2 fixation, permitting investigators to study the genetic diversity of diazotrophs in nature and target potential participants in N2 fixation. To date there have been limited, standardized pipelines for analyzing the nifH functional gene, which is in stark contrast to the 16S rRNA gene. Here we present a bioinformatics pipeline for processing nifH amplicon datasets - NifMAP ('NifH MiSeq Illumina Amplicon Analysis Pipeline'), which as a novel aspect uses Hidden-Markov Models to filter out homologous genes to nifH. By using this pipeline, we evaluated the broadly inclusive primer pairs (Ueda19F-R6, IGK3-DVV, and F2-R6) that target the nifH gene. To evaluate any systematic biases, the nifH gene was amplified with the aforementioned primer pairs in a diverse collection of environmental samples (soils, rhizosphere and roots samples, biological soil crusts and estuarine samples), in addition to a nifH mock community consisting of six phylogenetically diverse members. We noted that all primer pairs co-amplified nifH homologs to varying degrees; up to 90% of the amplicons were nifH homologs with IGK3-DVV in some samples (rhizosphere and roots from tall oat-grass). In regards to specificity, we observed some degree of bias across the primer pairs. For example, primer pair F2-R6 discriminated against cyanobacteria (amongst others), yet captured many sequences from subclusters IIIE and IIIL-N. These aforementioned subclusters were largely missing by the primer pair IGK3-DVV, which also tended to discriminate against Alphaproteobacteria, but amplified sequences within clusters IIIC (affiliated with Clostridia) and clusters IVB and IVC. Primer pair Ueda19F-R6 exhibited the least bias and successfully captured diazotrophs in cluster I and subclusters IIIE, IIIL, IIIM, and IIIN, but tended to discriminate against Firmicutes and subcluster IIIC. Taken together, our newly established bioinformatics pipeline, NifMAP, along with our systematic evaluations of nifH primer pairs permit more robust, high-throughput investigations of diazotrophs in diverse environments.", "keywords": ["0301 basic medicine", "DIVERSITY", "nifH gene", "Microbiology", "03 medical and health sciences", "NifMAP", "Nitrogen fixation", "PARTICULATE METHANE MONOOXYGENASE", "MOLYBDENUM-NITROGENASE", "Primer evaluation", "MICROORGANISMS", "NifH gene", "2. Zero hunger", "106022 Mikrobiologie", "0303 health sciences", "SEQUENCES", "GROUP-IV NITROGENASE", "AMPLIFICATION", "PERFORMANCE", "16. Peace & justice", "QR1-502", "primer evaluation", "nitrogen fixation", "106022 Microbiology", "COMMUNITIES", "N-2 FIXATION", "Illumina amplicon sequencing"]}, "links": [{"href": "https://doi.org/10.3389/fmicb.2018.00703"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Frontiers%20in%20Microbiology", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.3389/fmicb.2018.00703", "name": "item", "description": "10.3389/fmicb.2018.00703", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.3389/fmicb.2018.00703"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2018-04-30T00:00:00Z"}}, {"id": "10.3390/plants10112419", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-07-27T16:21:56Z", "type": "Journal Article", "created": "2021-11-09", "title": "Legume-Based Mobile Green Manure Can Increase Soil Nitrogen Availability and Yield of Organic Greenhouse Tomatoes", "description": "

Information about the availability of soil mineral nitrogen (N) in organic greenhouse tomatoes after the application of mobile green manure (MGM), and its impact on plant nutrient status and yield is scarce. Considering this knowledge gap, the effects of legume biomass from faba beans that are cultivated outdoors (FAB), or from feed-grade alfalfa pellets at two different doses (AAL = 330 g m\uffe2\uff88\uff922; AAH = 660 g m\uffe2\uff88\uff922) that were applied as MGM on the nutrition and yield of an organic greenhouse crop of tomatoes were evaluated. All of the MGM treatments increased the mineral N concentrations in the soil throughout the cropping period, and the total N concentration in tomato leaves when compared to the untreated control. FAB and AAH treatments had a stronger impact than AAL in all of the measured parameters. In addition, AAL, AAH, and FAB treatments increased the yield compared to the control by 19%, 33%, and 36%, respectively. The application of MGM, either as faba bean fresh biomass or as alfalfa dry pellets, in organic greenhouse tomatoes significantly increased the plant available soil N, improved N nutrition, and enhanced the fruit yield. However, the N mineralization rates after the MGM application were excessive during the initial cropping stages, followed by a marked decrease thereafter. This may impose an N deficiency during the late cropping period.

", "keywords": ["2. Zero hunger", "Solanum lycopersicum", "soil nitrogen", "alfalfa pellet", "Botany", "04 agricultural and veterinary sciences", "Alfalfa pellet; Biological nitrogen fixation; Faba bean; Organic tomato; Rhizobia; Soil nitrogen; Solanum lycopersicum", "biological nitrogen fixation", "rhizobia", "faba bean", "Article", "QK1-989", "0401 agriculture", " forestry", " and fisheries", "organic tomato"]}, "links": [{"href": "http://www.mdpi.com/2223-7747/10/11/2419/pdf"}, {"href": "https://iris.unito.it/bitstream/2318/1818902/1/Plants_10_2419.pdf"}, {"href": "https://www.mdpi.com/2223-7747/10/11/2419/pdf"}, {"href": "https://doi.org/10.3390/plants10112419"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Plants", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.3390/plants10112419", "name": "item", "description": "10.3390/plants10112419", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.3390/plants10112419"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2021-11-09T00:00:00Z"}}, {"id": "10.3390/plants12071443", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-07-27T16:21:56Z", "type": "Journal Article", "created": "2023-03-24", "title": "Do Nitrogen and Phosphorus Additions Affect Nitrogen Fixation Associated with Tropical Mosses?", "description": "

Tropical cloud forests are characterized by abundant and biodiverse mosses which grow epiphytically as well as on the ground. Nitrogen (N)-fixing cyanobacteria live in association with most mosses, and contribute greatly to the N pool via biological nitrogen fixation (BNF). However, the availability of nutrients, especially N and phosphorus (P), can influence BNF rates drastically. To evaluate the effects of increased N and P availability on BNF in mosses, we conducted a laboratory experiment where we added N and P, in isolation and combined, to three mosses (Campylopus sp., Dicranum sp. and Thuidium peruvianum) collected from a cloud forest in Peru. Our results show that N addition almost completely inhibited BNF within a day, whereas P addition caused variable results across moss species. Low N2 fixation rates were observed in Campylopus sp. across the experiment. BNF in Dicranum sp. was decreased by all nutrients, while P additions seemed to promote BNF in T. peruvianum. Hence, each of the three mosses contributes distinctively to the ecosystem N pool depending on nutrient availability. Moreover, increased N input will likely significantly decrease BNF associated with mosses also in tropical cloud forests, thereby limiting N input to these ecosystems via the moss-cyanobacteria pathway.

", "keywords": ["nutrient limitation", "cyanobacteria; ecosystem ecology; global change; mosses; nitrogen fixation; nutrient limitation; phosphorus; tropical cloud forest", "Botany", "ecosystem ecology", "15. Life on land", "Milj\u00f6vetenskap", "cyanobacteria", "Article", "mosses", "13. Climate action", "nitrogen fixation", "QK1-989", "tropical cloud forest", "phosphorus", "Environmental Sciences", "global change"]}, "links": [{"href": "http://www.mdpi.com/2223-7747/12/7/1443/pdf"}, {"href": "https://www.mdpi.com/2223-7747/12/7/1443/pdf"}, {"href": "https://doi.org/10.3390/plants12071443"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Plants", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.3390/plants12071443", "name": "item", "description": "10.3390/plants12071443", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.3390/plants12071443"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2023-03-24T00:00:00Z"}}, {"id": "10.5061/dryad.70q4744", "type": "Feature", "geometry": null, "properties": {"license": "unspecified", "updated": "2026-07-27T16:22:25Z", "type": "Dataset", "title": "Data from: Feedbacks between nitrogen fixation and soil organic matter increase ecosystem functions in diversified agroecosystems", "description": "unspecifiedSoil and N2 FixationMerged baseline data from soil samples collected in fall 2014 or spring 2015 with data on biological nitrogen fixation by hairy vetch at biomass sampling in spring of 2016.Soil_2016BNF.csvN2 Fixation 2017Aboveground biomass and nitrogen content for hairy vetch and cereal rye, and biological nitrogen fixation by hairy vetch, measured in May, 2017.BNF2017.csvChange in soilEffect sizes for measured soil properties (i.e., the change in the property following two years of the cover crop mixture compared to the no cover control), calculated by subtracting the final value for each soil parameter measured in the mixture treatment from the final value measured in the no cover crop control at the May 2017 sampling.EffectSizes.csv", "keywords": ["2. Zero hunger", "13. Climate action", "Particulate organic matter", "soil organic matter", "agroecosystem", "Secale cereale L.", "mineralization", "cover crop", "Biological nitrogen fixation", "15. Life on land", "Soil carbon", "Vicia villosa L."], "contacts": [{"organization": "Blesh, Jennifer", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.5061/dryad.70q4744"}, {"rel": "self", "type": "application/geo+json", "title": "10.5061/dryad.70q4744", "name": "item", "description": "10.5061/dryad.70q4744", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.5061/dryad.70q4744"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2019-07-16T00:00:00Z"}}, {"id": "10.5061/dryad.9zw3r229b", "type": "Feature", "geometry": null, "properties": {"license": "unspecified", "updated": "2026-07-27T16:22:27Z", "type": "Dataset", "title": "Data from: Switchgrass rhizosphere metabolite chemistry driven by nitrogen availability", "description": "unspecifiedPlants and soil microorganisms interact closely in the rhizosphere where plants may exchange carbon (C) for functional benefits from the microbial community. For example, the bioenergy crop, switchgrass (Panicum virgatum) is thought to exchange root-exuded C for nitrogen (N) fixed by diazotrophs (free-living N-fixers). However, this interaction is not well characterized and it is not known how or if switchgrass responds to diazotrophs or their activity. To explore this question, we assessed rhizosphere metabolite chemistry of switchgrass grown in a hydroponic system under two N levels and under inoculated or uninoculated conditions. Plants were grown with the inoculum Azotobacter vinelandii DJ for three days before harvest. We found switchgrass root exudate chemistry to be driven by N availability. Total metabolite concentrations were generally greater under high N versus low N and unaffected by inoculation. Examination of rhizosphere chemical fingerprints indicates metabolite chemistry was also driven strongly by N availability with a greater relative abundance of carbohydrates under high N and greater relative abundance of organic acids under low N. We also found evidence of changes in rhizosphere chemical fingerprints by inoculation treatment. However, we found little evidence of N treatment and inoculation interaction effects which suggests this response is not directly mediated by N availability.", "keywords": ["2. Zero hunger", "Switchgrass", "Rhizosphere", "NMR-based metabolomics", "Diazotroph", "15. Life on land", "Free-living nitrogen fixation"], "contacts": [{"organization": "Smercina, Darian, Bowsher, Alan W, Evans, Sarah E, Friesen, Maren L, Eder, Elizabeth K, Hoyt, David W, Tiemann, Lisa K,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.5061/dryad.9zw3r229b"}, {"rel": "self", "type": "application/geo+json", "title": "10.5061/dryad.9zw3r229b", "name": "item", "description": "10.5061/dryad.9zw3r229b", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.5061/dryad.9zw3r229b"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2020-03-26T00:00:00Z"}}, {"id": "11353/10.1033274", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-07-27T16:26:12Z", "type": "Journal Article", "created": "2018-04-30", "title": "Evaluation of Primers Targeting the Diazotroph Functional Gene and Development of NifMAP \u2013 A Bioinformatics Pipeline for Analyzing nifH Amplicon Data", "description": "Diazotrophic microorganisms introduce biologically available nitrogen (N) to the global N cycle through the activity of the nitrogenase enzyme. The genetically conserved dinitrogenase reductase (nifH) gene is phylogenetically distributed across four clusters (I-IV) and is widely used as a marker gene for N2 fixation, permitting investigators to study the genetic diversity of diazotrophs in nature and target potential participants in N2 fixation. To date there have been limited, standardized pipelines for analyzing the nifH functional gene, which is in stark contrast to the 16S rRNA gene. Here we present a bioinformatics pipeline for processing nifH amplicon datasets - NifMAP ('NifH MiSeq Illumina Amplicon Analysis Pipeline'), which as a novel aspect uses Hidden-Markov Models to filter out homologous genes to nifH. By using this pipeline, we evaluated the broadly inclusive primer pairs (Ueda19F-R6, IGK3-DVV, and F2-R6) that target the nifH gene. To evaluate any systematic biases, the nifH gene was amplified with the aforementioned primer pairs in a diverse collection of environmental samples (soils, rhizosphere and roots samples, biological soil crusts and estuarine samples), in addition to a nifH mock community consisting of six phylogenetically diverse members. We noted that all primer pairs co-amplified nifH homologs to varying degrees; up to 90% of the amplicons were nifH homologs with IGK3-DVV in some samples (rhizosphere and roots from tall oat-grass). In regards to specificity, we observed some degree of bias across the primer pairs. For example, primer pair F2-R6 discriminated against cyanobacteria (amongst others), yet captured many sequences from subclusters IIIE and IIIL-N. These aforementioned subclusters were largely missing by the primer pair IGK3-DVV, which also tended to discriminate against Alphaproteobacteria, but amplified sequences within clusters IIIC (affiliated with Clostridia) and clusters IVB and IVC. Primer pair Ueda19F-R6 exhibited the least bias and successfully captured diazotrophs in cluster I and subclusters IIIE, IIIL, IIIM, and IIIN, but tended to discriminate against Firmicutes and subcluster IIIC. Taken together, our newly established bioinformatics pipeline, NifMAP, along with our systematic evaluations of nifH primer pairs permit more robust, high-throughput investigations of diazotrophs in diverse environments.", "keywords": ["0301 basic medicine", "DIVERSITY", "nifH gene", "Microbiology", "03 medical and health sciences", "NifMAP", "Nitrogen fixation", "PARTICULATE METHANE MONOOXYGENASE", "MOLYBDENUM-NITROGENASE", "Primer evaluation", "MICROORGANISMS", "NifH gene", "2. Zero hunger", "106022 Mikrobiologie", "0303 health sciences", "SEQUENCES", "GROUP-IV NITROGENASE", "AMPLIFICATION", "PERFORMANCE", "16. Peace & justice", "QR1-502", "primer evaluation", "nitrogen fixation", "106022 Microbiology", "COMMUNITIES", "N-2 FIXATION", "Illumina amplicon sequencing"]}, "links": [{"href": "https://doi.org/11353/10.1033274"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Frontiers%20in%20Microbiology", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "11353/10.1033274", "name": "item", "description": "11353/10.1033274", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/11353/10.1033274"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2018-04-30T00:00:00Z"}}, {"id": "10.5194/bg-8-353-2011", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-07-27T16:22:42Z", "type": "Journal Article", "created": "2011-02-14", "title": "Free Atmospheric Co2 Enrichment Increased Above Ground Biomass But Did Not Affect Symbiotic N-2-Fixation And Soil Carbon Dynamics In A Mixed Deciduous Stand In Wales", "description": "

Abstract. Through increases in net primary production (NPP), elevated CO2 is hypothesized to increase the amount of plant litter entering the soil. The fate of this extra carbon on the forest floor or in mineral soil is currently not clear. Moreover, increased rates of NPP can be maintained only if forests can escape nitrogen limitation. In a Free atmospheric CO2 Enrichment (FACE) experiment near Bangor, Wales, 4 ambient and 4 elevated [CO2] plots were planted with patches of Betula pendula, Alnus glutinosa and Fagus sylvatica on a former arable field. After 4 years, biomass averaged for the 3 species was 5497 (se 270) g m\uffe2\uff88\uff922 in ambient and 6450 (se 130) g m\uffe2\uff88\uff922 in elevated [CO2] plots, a significant increase of 17% (P = 0.018). During that time, only a shallow L forest floor litter layer had formed due to intensive bioturbation. Total soil C and N contents increased irrespective of treatment and species as a result of afforestation. We could not detect an additional C sink in the soil, nor were soil C stabilization processes affected by elevated [CO2]. We observed a decrease of leaf N content in Betula and Alnus under elevated [CO2], while the soil C/N ratio decreased regardless of CO2 treatment. The ratio of N taken up from the soil and by N2-fixation in Alnus was not affected by elevated [CO2]. We infer that increased nitrogen use efficiency is the mechanism by which increased NPP is sustained under elevated [CO2] at this site.

", "keywords": ["rotation poplar plantation", "0106 biological sciences", "0301 basic medicine", "elevated co2", "QE1-996.5", "Ecology", "dinitrogen fixation", "mineral soil", "natural n-15 abundance", "face", "Geology", "alnus-glutinosa", "15. Life on land", "pine forest", "01 natural sciences", "03 medical and health sciences", "Life", "13. Climate action", "QH501-531", "nitrogen-use efficiency", "organic-matter", "QH540-549.5"]}, "links": [{"href": "https://doi.org/10.5194/bg-8-353-2011"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Biogeosciences", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.5194/bg-8-353-2011", "name": "item", "description": "10.5194/bg-8-353-2011", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.5194/bg-8-353-2011"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2011-02-14T00:00:00Z"}}, {"id": "2764305888", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-07-27T16:27:11Z", "type": "Journal Article", "created": "2022-10-18", "title": "Application of stable\u2010isotope labelling techniques for the detection of active diazotrophs", "description": "Summary

Investigating active participants in the fixation of dinitrogen gas is vital as N is often a limiting factor for primary production. Biological nitrogen fixation is performed by a diverse guild of bacteria and archaea (diazotrophs), which can be free\uffe2\uff80\uff90living or symbionts. Free\uffe2\uff80\uff90living diazotrophs are widely distributed in the environment, yet our knowledge about their identity and ecophysiology is still limited. A major challenge in investigating this guild is inferring activity from genetic data as this process is highly regulated. To address this challenge, we evaluated and improved several 15N\uffe2\uff80\uff90based methods for detecting N2 fixation activity (with a focus on soil samples) and studying active diazotrophs. We compared the acetylene reduction assay and the 15N2 tracer method and demonstrated that the latter is more sensitive in samples with low activity. Additionally, tracing 15N into microbial RNA provides much higher sensitivity compared to bulk soil analysis. Active soil diazotrophs were identified with a 15N\uffe2\uff80\uff90RNA\uffe2\uff80\uff90SIP approach optimized for environmental samples and benchmarked to 15N\uffe2\uff80\uff90DNA\uffe2\uff80\uff90SIP. Lastly, we investigated the feasibility of using SIP\uffe2\uff80\uff90Raman microspectroscopy for detecting 15N\uffe2\uff80\uff90labelled cells. Taken together, these tools allow identifying and investigating active free\uffe2\uff80\uff90living diazotrophs in a highly sensitive manner in diverse environments, from bulk to the single\uffe2\uff80\uff90cell level.