{"type": "FeatureCollection", "features": [{"id": "10.1007/pl00008869", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-27T16:14:39Z", "type": "Journal Article", "created": "2006-04-10", "title": "Combined Effects Of Atmospheric Co2 And N Availability On The Belowground Carbon And Nitrogen Dynamics Of Aspen Mesocosms", "description": "It is uncertain whether elevated atmospheric CO2 will increase C storage in terrestrial ecosystems without concomitant increases in plant access to N. Elevated CO2 may alter microbial activities that regulate soil N availability by changing the amount or composition of organic substrates produced by roots. Our objective was to determine the potential for elevated CO2 to change N availability in an experimental plant-soil system by affecting the acquisition of root-derived C by soil microbes. We grew Populus tremuloides (trembling aspen) cuttings for 2 years under two levels of atmospheric CO2 (36.7 and 71.5 Pa) and at two levels of soil N (210 and 970 \u00b5g N g-1). Ambient and twice-ambient CO2 concentrations were applied using open-top chambers, and soil N availability was manipulated by mixing soils differing in organic N content. From June to October of the second growing season, we measured midday rates of soil respiration. In August, we pulse-labeled plants with 14CO2 and measured soil 14CO2 respiration and the 14C contents of plants, soils, and microorganisms after a 6-day chase period. In conjunction with the August radio-labeling and again in October, we used 15N pool dilution techniques to measure in situ rates of gross N mineralization, N immobilization by microbes, and plant N uptake. At both levels of soil N availability, elevated CO2 significantly increased whole-plant and root biomass, and marginally increased whole-plant N capital. Significant increases in soil respiration were closely linked to increases in root biomass under elevated CO2. CO2 enrichment had no significant effect on the allometric distribution of biomass or 14C among plant components, total 14C allocation belowground, or cumulative (6-day) 14CO2 soil respiration. Elevated CO2 significantly increased microbial 14C contents, indicating greater availability of microbial substrates derived from roots. The near doubling of microbial 14C contents at elevated CO2 was a relatively small quantitative change in the belowground C cycle of our experimental system, but represents an ecologically significant effect on the dynamics of microbial growth. Rates of plant N uptake during both 6-day periods in August and October were significantly greater at elevated CO2, and were closely related to fine-root biomass. Gross N mineralization was not affected by elevated CO2. Despite significantly greater rates of N immobilization under elevated CO2, standing pools of microbial N were not affected by elevated CO2, suggesting that N was cycling through microbes more rapidly. Our results contained elements of both positive and negative feedback hypotheses, and may be most relevant to young, aggrading ecosystems, where soil resources are not yet fully exploited by plant roots. If the turnover of microbial N increases, higher rates of N immobilization may not decrease N availability to plants under elevated CO2.", "keywords": ["0106 biological sciences", "root-: biomass-", "Ecology and Evolutionary Biology", "nitrogen-fixation", "Environmental-Sciences)", "01 natural sciences", "nitrogen", "biomass-", "nitrogen-cycle", "nitrogen-", "Microorganisms-", "carbon-14", "124-38-9: CARBON DIOXIDE", "C Cycle", "Spermatophytes-", "Spermatophyta-", "Key Words Atmospheric CO2", "Cellular and Developmental Biology", "Populus Tremuloides Michx", "2. Zero hunger", "carbon-dioxide: atmospheric-", "plant-nutrition", "Climatology- (Environmental-Sciences)", "Angiosperms-", "Angiospermae-", "Plants-", "Natural Resources and Environment", "04 agricultural and veterinary sciences", "global-climate-change", "microbe- (Microorganisms-)", "7727-37-9: NITROGEN", "chemical-composition", "carbon-sequestration", "mineral-uptake", "soil-biology", "Science", "Vascular-Plants", "poplars-", "respiration-", "carbon-dioxide-enrichment", "carbon-dioxide", "Populus-tremuloides [trembling-aspen] (Salicaceae-)", "carbon-cycle", "Health Sciences", "Salicaceae-: Dicotyledones-", "soil-respiration", "content", "Plantae-", "14762-75-5: CARBON-14", "mineralization-", "Molecular", "forest-soils", "15. Life on land", "Rhizodeposition", "soil-flora", "N Cycle", "13. Climate action", "cuttings-", "roots-", "Legacy", "Terrestrial-Ecology (Ecology-", "0401 agriculture", " forestry", " and fisheries", "Dicots-", "ecosystems-"], "contacts": [{"organization": "Mikan, Carl J., Zak, Donald R., Kubiske, Mark E., Pregitzer, Kurt S.,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.1007/pl00008869"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Oecologia", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1007/pl00008869", "name": "item", "description": "10.1007/pl00008869", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1007/pl00008869"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2000-08-23T00:00:00Z"}}, {"id": "10.1007/s004420050619", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-27T16:14:50Z", "type": "Journal Article", "created": "2002-08-25", "title": "Soil Carbon And Nitrogen In A Pine-Oak Sand Plain In Central Massachusetts: Role Of Vegetation And Land-Use History", "description": "Over the last 150 years much of the landscape of eastern North America has been transformed from predominantly agricultural lands to forest. Although cultivation strongly affects important ecosystem processes such as biomass accumulation, soil organic matter dynamics, and nitrogen cycling, recovery of these processes after abandonment is insufficiently understood. We examined soil carbon and nitrogen pools and nitrogen dynamics for 16 plots on a central Massachusetts sand plain, over 80% of which had been cultivated and subsequently abandoned at least 40 years ago. The two youngest old-field forests, located on sites abandoned 40-60 years prior to our sampling, had the lowest mineral soil carbon content (0-15\u2009cm), 31% less than the average of unplowed soils. Soil carbon concentration and loss-on-ignition were significantly higher in unplowed soils than in all plowed soils, but these differences were offset by the higher bulk density in formerly plowed soils, leading to no significant differences in C content between plowed and unplowed soil. Soil C:N ratios were lower in formerly plowed soils (26.2) than in unplowed soils (28.0). While soil N content was not affected by land-use history or vegetation type, net N mineralization showed much greater variation. In situ August net nitrogen mineralization varied nearly 40-fold between stand types: lowest in pitch pine and white pine stands (-0.13 and 0.10\u2009kg\u2009N\u2009ha-1\u200928\u2009day-1), intermediate in scrub oak stands (0.48\u2009kg\u2009N\u2009ha-1\u200928\u2009day-1) and highest in aspen and mixed oak stands (1.34-3.11\u2009kg\u2009N\u2009ha-1\u200928\u2009day-1). Mineralization was more strongly related to present vegetation than to land-use history or soil N content. Appreciable net nitrification was observed only in the most recently abandoned aspen plot (0.82\u2009kg\u2009N\u2009ha-1\u200928\u2009day-1), suggesting that recent disturbance and residual agricultural lime stimulated nitrification. Carbon:nitrogen ratios increased and pH declined with stand age. Higher bulk density, lower loss-on-ignition and C:N ratios, and slightly lower C concentrations in the surface mineral soil are the persistent legacies of agriculture on soil properties. Short-term agricultural use and the low initial C and N concentrations in these sandy soils appear to have resulted in less persistent impacts of agriculture on soil C and N content and N cycling.", "keywords": ["0106 biological sciences", "soil-properties", "Forests", "Environmental-Sciences)", "01 natural sciences", "nitrogen", "variation-", "Soil", "Quercus", "soil-nitrogen", "nitrogen-", "cultivation-", "cycling-", "soil-organic-matter", "vegetation-history", "sandy-soils", "soil-carbon", "2. Zero hunger", "7440-44-0: CARBON", "carbon-", "pines-", "Soil-studies", "land-use-history", "04 agricultural and veterinary sciences", "pine-oak-sand-plain", "Chemistry", "North-America", "Nearctic-region)", "Massachusetts", "agricultural-practice", "biomass-production", "trees-", "7727-37-9: Nitrogen", "nitrification-", "United-States", "forests-", "Agricultural ecosystems", "land-use", "Massachusetts- (USA-", "forest-lands", "Nutrient dynamics", "vegetation-type", "USA", "Vegetation", "mineralization-", "15. Life on land", "Pinus", "soil-types", "Terrestrial-Ecology (Ecology-", "0401 agriculture", " forestry", " and fisheries", "agricultural-land", "ecosystems-"], "contacts": [{"organization": "Campton, Jana E., Boone, Richard D., Motzkin, Glenn, Foster, David R.,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.1007/s004420050619"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Oecologia", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1007/s004420050619", "name": "item", "description": "10.1007/s004420050619", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1007/s004420050619"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "1998-10-01T00:00:00Z"}}, {"id": "10.1007/s100210000025", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-27T16:14:55Z", "type": "Journal Article", "created": "2002-07-25", "title": "Controls On Soil Carbon Dioxide And Methane Fluxes In A Variety Of Taiga Forest Stands In Interior Alaska", "description": "CO2 and CH4 fluxes were monitored over 4 years in a range of taiga forests along the Tanana River in interior Alaska. Floodplain alder and white spruce sites and upland birch/aspen and white spruce sites were examined. Each site had control, fertilized, and sawdust amended plots; flux measurements began during the second treatment year. CO2 emissions decreased with successional age across the sites (alder, birch/aspen, and white spruce, in order of succession) regardless of landscape position. Although CO2 fluxes showed an exponential relationship with soil temperature, the response of CO2 production to moisture fit an asymptotic model. Of the manipulations, only N fertilization had an effect on CO2 flux, decreasing flux in the floodplain sites but increasing it in the birch/aspen site. Landscape position was the best predictor of CH4 flux. The two upland sites consumed CH4 at similar rates (approximately 0.5 mg C m\u22122 d\u22121), whereas the floodplain sites had lower consumption rates (0\u20130.3 mg C m\u22122 d\u22121). N fertilization and sawdust both inhibited CH4 consumption in the upland birch/aspen and floodplain spruce sites but not in the upland spruce site. The biological processes driving CO2 fluxes were sensitive to temperature, moisture, and vegetation, whereas CH4 fluxes were sensitive primarily to landscape position and biogeochemical disturbances. Hence, climate change effects on C-gas flux in taiga forest soils will depend on the relationship between soil temperature and moisture and the concomitant changes in soil nutrient pools and cycles.", "keywords": ["landscape-ecology", "Betulaceae-: Dicotyledones-", "flux-", "soil-nutrient-pools", "Coniferopsida-: Gymnospermae-", "Vascular-Plants", "forests-", "Environmental-Sciences)", "carbon-dioxide", "nitrogen-fertilizers", "01 natural sciences", "carbon-dioxide: emissions-", "nitrogen-: fertilization-", "vegetation-", "birch- (Betulaceae-)", "124-38-9: CARBON DIOXIDE", "Spermatophytes-", "Spermatophyta-", "74-82-8: METHANE", "Plantae-", "white-spruce (Coniferopsida-)", "successional-age", "boreal-forests", "environmental-temperature", "0105 earth and related environmental sciences", "taiga-forest-stands", "Angiosperms-", "Gymnosperms-", "Angiospermae-", "Plants-", "sawdust-", "methane-", "15. Life on land", "North-America", "Nearctic-region)", "floodplains-", "mathematical-models", "13. Climate action", "alder- (Betulaceae-)", "upland-sites", "Alaska- (USA-", "climate-change", "Terrestrial-Ecology (Ecology-", "7727-37-9: NITROGEN", "Dicots-", "methane-: consumption-", "moisture-", "climatic-change", "temperature-"]}, "links": [{"href": "https://doi.org/10.1007/s100210000025"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Ecosystems", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1007/s100210000025", "name": "item", "description": "10.1007/s100210000025", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1007/s100210000025"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2000-05-10T00:00:00Z"}}, {"id": "10.1016/s0378-1127(00)00282-6", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-27T16:17:51Z", "type": "Journal Article", "created": "2002-07-25", "title": "Effects of forest management on soil c and n storage: meta analysis", "description": "Abstract   The effects of forest management on soil carbon (C) and nitrogen (N) are important to understand not only because these are often master variables determining soil fertility but also because of the role of soils as a source or sink for C on a global scale. This paper reviews the literature on forest management effects on soil C and N and reports the results of a meta analysis of these data. The meta analysis showed that forest harvesting, on average, had little or no effect on soil C and N. Significant effects of harvest type and species were noted, with sawlog harvesting causing increases (+18%) in soil C and N and whole-tree harvesting causing decreases (\u22126%). The positive effect of sawlog harvesting appeared to be restricted to coniferous species. Fire resulted in no significant overall effects of fire on either C or N (when categories were combined); but there was a significant effect of time since fire, with an increase in both soil C and N after 10 years (compared to controls). Significant differences among fire treatments were found, with the counterintuitive result of lower soil C following prescribed fire and higher soil C following wildfire. The latter is attributed to the sequestration of charcoal and recalcitrant, hydrophobic organic matter and to the effects of naturally invading, post-fire, N-fixing vegetation. Both fertilization and N-fixing vegetation caused marked overall increases in soil C and N.", "keywords": ["0106 biological sciences", "sawlog-harvesting: harvesting-method", "Coniferopsida-: Gymnospermae-", "Vascular-Plants", "Eucalyptus-spp. (Myrtaceae-)", "01 natural sciences", "carbon-: soil-storage", "Salicaceae-: Dicotyledones-", "Spermatophytes-", "Spermatophyta-", "Plantae-", "Forest Sciences", "Pinus-spp. (Coniferopsida-)", "Picea-abies (Coniferopsida-)", "meta-analysis: statistical-method", "2. Zero hunger", "7440-44-0: CARBON", "Angiosperms-", "Myrtaceae-: Dicotyledones-", "Gymnosperms-", "Angiospermae-", "Plants-", "04 agricultural and veterinary sciences", "15. Life on land", "Soil-Science", "whole-tree-harvesting: harvesting-method", "Populus-tremuloides (Salicaceae-)", "Forestry-", "7727-37-9: NITROGEN", "prescribed-burning: forestry-method", "0401 agriculture", " forestry", " and fisheries", "Dicots-", "nitrogen-: soil-storage"], "contacts": [{"organization": "Peter S. Curtis, Dale W. Johnson, Dale W. Johnson,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.1016/s0378-1127(00)00282-6"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Forest%20Ecology%20and%20Management", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1016/s0378-1127(00)00282-6", "name": "item", "description": "10.1016/s0378-1127(00)00282-6", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1016/s0378-1127(00)00282-6"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2001-01-01T00:00:00Z"}}, {"id": "10.2307/2640985", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-27T16:21:20Z", "type": "Journal Article", "created": "2006-04-17", "description": "Elevated atmospheric CO2 has the potential to increase the production and alter the chemistry of organic substrates entering soil from plant production, the magnitude of which is constrained by soil-N availability. Because microbial growth in soil is limited by substrate inputs from plant production, we reasoned that changes in the amount and chemistry of these organic substrates could affect the composition of soil microbial com- munities and the cycling of N in soil. We studied microbial community composition and soil-N transformations beneath Populus tremuloides Michx. growing under experimental atmospheric CO2 (35.7 and 70.7 Pa) and soil-N-availability (low N 5 61 ng N\u00b7g 21 \u00b7d 21 and high N 5 319 ng N\u00b7g 21 \u00b7d 21 ) treatments. Atmospheric CO2 concentration was modified in large, open-top chambers, and we altered soil-N availability in open-bottom root boxes by mixing different proportions of A and C horizon material. We used phospholipid fatty-acid analysis to gain insight into microbial community composition and coupled this analysis to measurements of soil-N transformations using 15 N-pool dilution techniques. The infor- mation presented here is part of an integrated experiment designed to elucidate the phys- iological mechanisms controlling the flow of C and N in the plant-soil system. Our ob- jectives were (1) to determine whether changes in plant growth and tissue chemistry alter microbial community composition and soil-N cycling in response to increasing atmospheric CO2 and soil-N availability and (2) to integrate the results of our experiment into a synthesis of elevated atmospheric CO2 and the cycling of C and N in terrestrial ecosystems. After 2.5 growing seasons, microbial biomass, gross N mineralization, microbial im- mobilization, and nitrification (gross and net) were equivalent at ambient and elevated CO2, suggesting that increases in fine-root production and declines in fine-root N concentration were insufficient to alter the influence of native soil organic matter on microbial physiology; this was the case in both low- and high-N soil. Similarly, elevated CO2 did not alter the proportion of bacterial, actinomycetal, or fungal phospholipid fatty acids in low-N or high-N soil, indicating that changes in substrate input from greater plant growth under elevated CO2 did not alter microbial community composition. Our results differ from a substantial number of studies reporting increases and decreases in soil-N cycling under elevated CO 2. From our analysis, it appears that soil-N cycling responds to elevated atmospheric CO 2 in experimental situations where plant roots have fully colonized the soil and root-associated C inputs are sufficient to modify the influence of native soil organic matter on microbial physiology. In young developing ecosystems where plant roots have not fully exploited the soil, microbial metabolism appears to be regulated by relatively large pools of soil organic matter, rather than by the additional input of organic substrates under elevated CO 2.", "keywords": ["measurement-", "soil microorganisms", "Ecology and Evolutionary Biology", "nitrogen-: cycling-", "feedback", "microbial community composition", "techniques-", "Environmental-Sciences)", "01 natural sciences", "litter-plant", "biomass-", "gross and net", "124-38-9: CARBON DIOXIDE", "Spermatophytes-", "cycling-", "soil-organic-matter", "mineralization", "Spermatophyta-", "responses-", "phospholipid-fatty-acids", "2. Zero hunger", "Climatology- (Environmental-Sciences)", "Angiosperms-", "Angiospermae-", "Plants-", "global climate change", "microbial immobilization", "nutrient-", "Soil-Science", "6. Clean water", "metabolism-", "soil-N transformations", "transformation-", "substrates-", "7727-37-9: NITROGEN", "atmosphere-", "elevated atmospheric", "570", "nitrification-", "nitrogen immobilization", "Science", "Vascular-Plants", "poplars-", "phospholipid fatty acids (PFLAs)", "carbon-dioxide", "growth-", "soil-microbial-community-composition", "Salicaceae-: Dicotyledones-", "microbial-flora", "Populus tremuloides", "Plantae-", "organic-matter", "consortia-", "0105 earth and related environmental sciences", "communities-", "ecosystem", "analysis-", "atmospheric CO2 and soil-N availability", "soil-availability", "mineralization-", "carbon dioxide", "fatty-acids", "15. Life on land", "substrate-input", "Populus-tremuloides (Salicaceae-)", "13. Climate action", "roots-", "Terrestrial-Ecology (Ecology-", "composition-", "Dicots-", "immobilization-", "seasons-", "ecosystems-"], "contacts": [{"organization": "Zak, Donald R., Pregitzer, Kurt S., Curtis, Peter S., Holmes, William E.,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.2307/2640985"}, {"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": "10.2307/2640985", "name": "item", "description": "10.2307/2640985", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.2307/2640985"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2000-02-01T00:00:00Z"}}], "links": [{"rel": "self", "type": "application/geo+json", "title": "This document as GeoJSON", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=7727-37-9%3A+NITROGEN&f=json", "hreflang": "en-US"}, {"rel": "alternate", "type": "text/html", "title": "This document as HTML", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=7727-37-9%3A+NITROGEN&f=html", "hreflang": "en-US"}, {"rel": "collection", "type": "application/json", "title": "Collection URL", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main", "hreflang": "en-US"}, {"type": "application/geo+json", "rel": "first", "title": "items (first)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=7727-37-9%3A+NITROGEN&", "hreflang": "en-US"}, {"rel": "last", "type": "application/geo+json", "title": "items (last)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=7727-37-9%3A+NITROGEN&offset=5", "hreflang": "en-US"}], "numberMatched": 5, "numberReturned": 5, "distributedFeatures": [], "timeStamp": "2026-07-27T20:59:53.979486Z"}