{"id":{"repo_id":"slu","oai_identifier":"oai:pub.epsilon.slu.se:142"},"canonical_url":"https://search.dev.ndltd.org/etd/slu/oai:pub.epsilon.slu.se:142","repository":{"repo_id":"slu","name":"Swedish University of Agricultural Sciences","base_url":"https://pub.epsilon.slu.se/cgi/oai2"},"display":{"title":"Nitrogen Turnover in Swedish Spruce Forest Ecosystems","abstract":"Nitrate leaching from growing forests is not yet a widespread problem in Sweden, but nitrogen (N) deposition and high N retention in the soil during recent decades might have changed forest ecosystems towards N saturation. In this thesis net N mineralisation (measured with in situ incubations) was tested as an index of N status. It was shown that historic land use and N deposition, natural or simulated in fertilisation experiments, had caused great differences in this index (4-104 kg N ha -1 yr -1 ) and that N leaching occurred at sites with high N status (net N mineralisation > 60 kg N ha -1 yr -1 ). The net N mineralisation was well correlated to C/N ratio, which could also be used as a N status index. The amount of nitrate lost was not dependent on N status or current N deposition, but rather to the total N flux density (deposition + net mineralisation). The relatively fast change (30 years) from a highly N limited ecosystem to a system apparently approaching the first stage of N saturation upon moderate N fertilisation (35 kg N ha -1 yr -1 ) motivates continued concern about N saturation in Sweden. Predicting future response to N deposition and forest management necessitates a thorough understanding of all important N fluxes, but the importance of organic N uptake in Swedish spruce forest ecosystems is still unclear. Budget calculations indicated that uptake of organic N is of great importance (80%) in low input areas. In high N-input plots the relative importance appeared lower (35%). However, soil solution samples from the forest floor contained low concentrations of both amino acids and inorganic N, and the lack of a clear dominance of amino acids might be explained by a tight circulation of amino acids, never releasing the amino acids into the soil solution fraction sampled with tension lysimeters","abstract_html":"Nitrate leaching from growing forests is not yet a widespread problem in Sweden, but nitrogen (N) deposition and high N retention in the soil during recent decades might have changed forest ecosystems towards N saturation. In this thesis net N mineralisation (measured with in situ incubations) was tested as an index of N status. It was shown that historic land use and N deposition, natural or simulated in fertilisation experiments, had caused great differences in this index (4-104 kg N ha -1 yr -1 ) and that N leaching occurred at sites with high N status (net N mineralisation > 60 kg N ha -1 yr -1 ). The net N mineralisation was well correlated to C/N ratio, which could also be used as a N status index. The amount of nitrate lost was not dependent on N status or current N deposition, but rather to the total N flux density (deposition + net mineralisation). The relatively fast change (30 years) from a highly N limited ecosystem to a system apparently approaching the first stage of N saturation upon moderate N fertilisation (35 kg N ha -1 yr -1 ) motivates continued concern about N saturation in Sweden. Predicting future response to N deposition and forest management necessitates a thorough understanding of all important N fluxes, but the importance of organic N uptake in Swedish spruce forest ecosystems is still unclear. Budget calculations indicated that uptake of organic N is of great importance (80%) in low input areas. In high N-input plots the relative importance appeared lower (35%). However, soil solution samples from the forest floor contained low concentrations of both amino acids and inorganic N, and the lack of a clear dominance of amino acids might be explained by a tight circulation of amino acids, never releasing the amino acids into the soil solution fraction sampled with tension lysimeters","abstract_has_math":false,"creators":["Pål Andersson"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2002,"date_issued":"2002-01","date_published":"2002-01","updated_at":"2026-07-24T04:35:38Z","subjects":["boreal forests","ecosystems","picea abies","roots","forest soils","nitrogen cycle","mineralization","cycling","fertilizer application","leaching","amino acids","soil solution","sweden","boreal","ecosystem recovery","fine root longevity","forest soil","mycorhiza","PnET-CN"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://pub.epsilon.slu.se/142/","outbound_label":"Repository record","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.issued","label":"Date","values":["2002-01"]},{"key":"dc:type","label":"Dc Type","values":["Doctoral thesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["boreal forests","ecosystems","picea abies","roots","forest soils","nitrogen cycle","mineralization","cycling","fertilizer application","leaching","amino acids","soil solution","sweden","boreal","ecosystem recovery","fine root longevity","forest soil","mycorhiza","PnET-CN"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://pub.epsilon.slu.se/142/","https://pub.epsilon.slu.se/142/1/91-576-6194-4.fulltext.pdf"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.other","label":"Dc Description Other","values":["Nitrate leaching from growing forests is not yet a widespread problem in Sweden, but nitrogen (N) deposition and high N retention in the soil during recent decades might have changed forest ecosystems towards N saturation. In this thesis net N mineralisation (measured with in situ incubations) was tested as an index of N status. It was shown that historic land use and N deposition, natural or simulated in fertilisation experiments, had caused great differences in this index (4-104 kg N ha -1 yr -1 ) and that N leaching occurred at sites with high N status (net N mineralisation > 60 kg N ha -1 yr -1 ). The net N mineralisation was well correlated to C/N ratio, which could also be used as a N status index. The amount of nitrate lost was not dependent on N status or current N deposition, but rather to the total N flux density (deposition + net mineralisation). The relatively fast change (30 years) from a highly N limited ecosystem to a system apparently approaching the first stage of N saturation upon moderate N fertilisation (35 kg N ha -1 yr -1 ) motivates continued concern about N saturation in Sweden. Predicting future response to N deposition and forest management necessitates a thorough understanding of all important N fluxes, but the importance of organic N uptake in Swedish spruce forest ecosystems is still unclear. Budget calculations indicated that uptake of organic N is of great importance (80%) in low input areas. In high N-input plots the relative importance appeared lower (35%). However, soil solution samples from the forest floor contained low concentrations of both amino acids and inorganic N, and the lack of a clear dominance of amino acids might be explained by a tight circulation of amino acids, never releasing the amino acids into the soil solution fraction sampled with tension lysimeters"]},{"key":"dc:title","label":"Title","values":["Nitrogen Turnover in Swedish Spruce Forest Ecosystems","Acta Universitatis Agriculturae Sueciae. Agraria"]}]}],"canonical_facts":{"dc:date.issued":["2002-01"],"dc:description.other":["Nitrate leaching from growing forests is not yet a widespread problem in Sweden, but nitrogen (N) deposition and high N retention in the soil during recent decades might have changed forest ecosystems towards N saturation. In this thesis net N mineralisation (measured with in situ incubations) was tested as an index of N status. It was shown that historic land use and N deposition, natural or simulated in fertilisation experiments, had caused great differences in this index (4-104 kg N ha -1 yr -1 ) and that N leaching occurred at sites with high N status (net N mineralisation > 60 kg N ha -1 yr -1 ). The net N mineralisation was well correlated to C/N ratio, which could also be used as a N status index. The amount of nitrate lost was not dependent on N status or current N deposition, but rather to the total N flux density (deposition + net mineralisation). The relatively fast change (30 years) from a highly N limited ecosystem to a system apparently approaching the first stage of N saturation upon moderate N fertilisation (35 kg N ha -1 yr -1 ) motivates continued concern about N saturation in Sweden. Predicting future response to N deposition and forest management necessitates a thorough understanding of all important N fluxes, but the importance of organic N uptake in Swedish spruce forest ecosystems is still unclear. Budget calculations indicated that uptake of organic N is of great importance (80%) in low input areas. In high N-input plots the relative importance appeared lower (35%). However, soil solution samples from the forest floor contained low concentrations of both amino acids and inorganic N, and the lack of a clear dominance of amino acids might be explained by a tight circulation of amino acids, never releasing the amino acids into the soil solution fraction sampled with tension lysimeters"],"dc:identifier.uri":["https://pub.epsilon.slu.se/142/","https://pub.epsilon.slu.se/142/1/91-576-6194-4.fulltext.pdf"],"dc:subject":["boreal forests","ecosystems","picea abies","roots","forest soils","nitrogen cycle","mineralization","cycling","fertilizer application","leaching","amino acids","soil solution","sweden","boreal","ecosystem recovery","fine root longevity","forest soil","mycorhiza","PnET-CN"],"dc:title":["Nitrogen Turnover in Swedish Spruce Forest Ecosystems","Acta Universitatis Agriculturae Sueciae. Agraria"],"dc:type":["Doctoral thesis"]},"updated_at":"2026-07-24T04:35:38Z"}