TY - GEN A1 - Kumar, Rohini A1 - Hesse, Fabienne A1 - Rao, P. Srinivasa A1 - Musolff, Andreas A1 - Jawitz, James A1 - Sarrazin, Francois A1 - Samaniego, Luis A1 - Fleckenstein, Jan H. A1 - Rakovec, Oldrich A1 - Thober, S. A1 - Attinger, Sabine T1 - Strong hydroclimatic controls on vulnerability to subsurface nitrate contamination across Europe T2 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Subsurface contamination due to excessive nutrient surpluses is a persistent and widespread problem in agricultural areas across Europe. The vulnerability of a particular location to pollution from reactive solutes, such as nitrate, is determined by the interplay between hydrologic transport and biogeochemical transformations. Current studies on the controls of subsurface vulnerability do not consider the transient behaviour of transport dynamics in the root zone. Here, using state-of-the-art hydrologic simulations driven by observed hydroclimatic forcing, we demonstrate the strong spatiotemporal heterogeneity of hydrologic transport dynamics and reveal that these dynamics are primarily controlled by the hydroclimatic gradient of the aridity index across Europe. Contrasting the space-time dynamics of transport times with reactive timescales of denitrification in soil indicate that similar to 75% of the cultivated areas across Europe are potentially vulnerable to nitrate leaching for at least onethird of the year. We find that neglecting the transient nature of transport and reaction timescale results in a great underestimation of the extent of vulnerable regions by almost 50%. Therefore, future vulnerability and risk assessment studies must account for the transient behaviour of transport and biogeochemical transformation processes. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1352 KW - travel time distributions KW - groundwater vulnerability KW - flux tracking KW - transit-time KW - water age KW - nitrogen KW - model KW - dynamics KW - pollution KW - patterns Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-549875 SN - 1866-8372 IS - 1 ER - TY - JOUR A1 - Kumar, Rohini A1 - Hesse, Fabienne A1 - Rao, P. Srinivasa A1 - Musolff, Andreas A1 - Jawitz, James A1 - Sarrazin, Francois A1 - Samaniego, Luis A1 - Fleckenstein, Jan H. A1 - Rakovec, Oldrich A1 - Thober, S. A1 - Attinger, Sabine T1 - Strong hydroclimatic controls on vulnerability to subsurface nitrate contamination across Europe JF - Nature Communications N2 - Subsurface contamination due to excessive nutrient surpluses is a persistent and widespread problem in agricultural areas across Europe. The vulnerability of a particular location to pollution from reactive solutes, such as nitrate, is determined by the interplay between hydrologic transport and biogeochemical transformations. Current studies on the controls of subsurface vulnerability do not consider the transient behaviour of transport dynamics in the root zone. Here, using state-of-the-art hydrologic simulations driven by observed hydroclimatic forcing, we demonstrate the strong spatiotemporal heterogeneity of hydrologic transport dynamics and reveal that these dynamics are primarily controlled by the hydroclimatic gradient of the aridity index across Europe. Contrasting the space-time dynamics of transport times with reactive timescales of denitrification in soil indicate that similar to 75% of the cultivated areas across Europe are potentially vulnerable to nitrate leaching for at least onethird of the year. We find that neglecting the transient nature of transport and reaction timescale results in a great underestimation of the extent of vulnerable regions by almost 50%. Therefore, future vulnerability and risk assessment studies must account for the transient behaviour of transport and biogeochemical transformation processes. KW - travel time distributions KW - groundwater vulnerability KW - flux tracking KW - transit-time KW - water age KW - nitrogen KW - model KW - dynamics KW - pollution KW - patterns Y1 - 2020 U6 - https://doi.org/10.1038/s41467-020-19955-8 SN - 2041-1723 VL - 11 IS - 1 SP - 1 EP - 10 PB - Nature Publishing Group UK CY - London ER - TY - JOUR A1 - Radosavljevic, Boris A1 - Lantuit, Hugues A1 - Knoblauch, Christian A1 - Couture, Nicole A1 - Herzschuh, Ulrike A1 - Fritz, Michael T1 - Arctic nearshore sediment dynamics - an example from Herschel Island - Qikiqtaruk, Canada JF - Journal of marine science and engineering N2 - Increasing arctic coastal erosion rates imply a greater release of sediments and organic matter into the coastal zone. With 213 sediment samples taken around Herschel Island-Qikiqtaruk, Canadian Beaufort Sea, we aimed to gain new insights on sediment dynamics and geochemical properties of a shallow arctic nearshore zone. Spatial characteristics of nearshore sediment texture (moderately to poorly sorted silt) are dictated by hydrodynamic processes, but ice-related processes also play a role. We determined organic matter (OM) distribution and inferred the origin and quality of organic carbon by C/N ratios and stable carbon isotopes delta C-13. The carbon content was higher offshore and in sheltered areas (mean: 1.0 wt.%., S.D.: 0.9) and the C/N ratios also showed a similar spatial pattern (mean: 11.1, S.D.: 3.1), while the delta C-13 (mean: -26.4 parts per thousand VPDB, S.D.: 0.4) distribution was more complex. We compared the geochemical parameters of our study with terrestrial and marine samples from other studies using a bootstrap approach. Sediments of the current study contained 6.5 times and 1.8 times less total organic carbon than undisturbed and disturbed terrestrial sediments, respectively. Therefore, degradation of OM and separation of carbon pools take place on land and continue in the nearshore zone, where OM is leached, mineralized, or transported beyond the study area. KW - permafrost KW - Arctic Ocean KW - stable carbon isotopes KW - nitrogen KW - sediment KW - chemistry KW - sediment dynamics KW - Beaufort Sea KW - grain size Y1 - 2022 U6 - https://doi.org/10.3390/jmse10111589 SN - 2077-1312 VL - 10 IS - 11 PB - MDPI CY - Basel ER - TY - JOUR A1 - Eckert, Sebastian A1 - Norell, Jesper A1 - Jay, Raphael Martin A1 - Fondell, Mattis A1 - Mitzner, Rolf A1 - Odelius, Michael A1 - Föhlisch, Alexander T1 - T-1 Population as the Driver of Excited-State Proton-Transfer in 2-Thiopyridone JF - Chemistry - a European journal N2 - Excited-state proton transfer (ESPT) is a fundamental process in biomolecular photochemistry, but its underlying mediators often evade direct observation. We identify a distinct pathway for ESPT in aqueous 2-thiopyridone, by employing transient N1s X-ray absorption spectroscopy and multi-configurational spectrum simulations. Photoexcitations to the singlet S-2 and S-4 states both relax promptly through intersystem crossing to the triplet T-1 state. The T-1 state, through its rapid population and near nanosecond lifetime, mediates nitrogen site deprotonation by ESPT in a secondary intersystem crossing to the S-0 potential energy surface. This conclusively establishes a dominant ESPT pathway for the system in aqueous solution, which is also compatible with previous measurements in acetonitrile. Thereby, the hitherto open questions of the pathway for ESPT in the compound, including its possible dependence on excitation wavelength and choice of solvent, are resolved. KW - excited-state proton-transfer KW - intersystem crossing KW - nitrogen KW - photochemistry KW - X-ray absorption Y1 - 2019 U6 - https://doi.org/10.1002/chem.201804166 SN - 0947-6539 SN - 1521-3765 VL - 25 IS - 7 SP - 1733 EP - 1739 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Lachmann, Sabrina C. A1 - Mettler-Altmann, Tabea A1 - Wacker, Alexander A1 - Spijkerman, Elly T1 - Nitrate or ammonium BT - Influences of nitrogen source on the physiology of a green alga JF - Ecology and evolution N2 - In freshwaters, algal species are exposed to different inorganic nitrogen (Ni) sources whose incorporation varies in biochemical energy demand. We hypothesized that due to the lesser energy requirement of ammonium (NH4+)-use, in contrast to nitrate (NO3-)-use, more energy remains for other metabolic processes, especially under CO2-and phosphorus (Pi) limiting conditions. Therefore, we tested differences in cell characteristics of the green alga Chlamydomonas acidophila grown on NH4+ or NO3- under covariation of CO2 and Pi-supply in order to determine limitations, in a full-factorial design. As expected, results revealed higher carbon fixation rates for NH4+ grown cells compared to growth with NO3- under low CO2 conditions. NO3- -grown cells accumulated more of the nine analyzed amino acids, especially under Pi-limited conditions, compared to cells provided with NH4+. This is probably due to a slower protein synthesis in cells provided with NO3-. In contrast to our expectations, compared to NH4+ -grown cells NO3- -grown cells had higher photosynthetic efficiency under Pi-limitation. In conclusion, growth on the Ni-source NH4+ did not result in a clearly enhanced Ci-assimilation, as it was highly dependent on Pi and CO2 conditions (replete or limited). Results are potentially connected to the fact that C. acidophila is able to use only CO2 as its inorganic carbon (Ci) source. KW - amino acids KW - carbon uptake kinetics KW - CO2 conditions KW - nitrogen KW - phosphorus limitation Y1 - 2019 U6 - https://doi.org/10.1002/ece3.4790 SN - 2045-7758 VL - 9 IS - 3 PB - Wiley CY - Hoboken ER - TY - GEN A1 - Eckert, Sebastian A1 - Norell, Jesper A1 - Miedema, Piter S. A1 - Beye, Martin A1 - Fondell, Mattis A1 - Quevedo, Wilson A1 - Kennedy, Brian A1 - Hantschmann, Markus A1 - Pietzsch, Annette A1 - van Kuiken, Benjamin E. A1 - Ross, Matthew A1 - Minitti, Michael P. A1 - Moeller, Stefan P. A1 - Schlotter, William F. A1 - Khalil, Munira A1 - Odelius, Michael A1 - Föhlisch, Alexander T1 - Ultrafast Independent N-H and N-C Bond Deformation Investigated with Resonant Inelastic X-Ray Scattering T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - The femtosecond excited-state dynamics following resonant photoexcitation enable the selective deformation of N-H and N-C chemical bonds in 2-thiopyridone in aqueous solution with optical or X-ray pulses. In combination with multiconfigurational quantum-chemical calculations, the orbital-specific electronic structure and its ultrafast dynamics accessed with resonant inelastic X-ray scattering at the N 1s level using synchrotron radiation and the soft X-ray free-electron laser LCLS provide direct evidence for this controlled photoinduced molecular deformation and its ultrashort time-scale. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1115 KW - nitrogen KW - photochemistry KW - protonation KW - RIXS (resonant inelastic X-ray scattering) KW - selective bond cleavage Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-436873 SN - 1866-8372 IS - 1115 ER - TY - JOUR A1 - Eckert, Sebastian A1 - Norell, Jesper A1 - Miedema, Piter S. A1 - Beye, Martin A1 - Fondell, Mattis A1 - Quevedo, Wilson A1 - Kennedy, Brian A1 - Hantschmann, Markus A1 - Pietzsch, Annette A1 - Van Kuiken, Benjamin E. A1 - Ross, Matthew A1 - Minitti, Michael P. A1 - Moeller, Stefan P. A1 - Schlotter, William F. A1 - Khalil, Munira A1 - Odelius, Michael A1 - Föhlisch, Alexander T1 - Ultrafast Independent N-H and N-C Bond Deformation Investigated with Resonant Inelastic X-Ray Scattering JF - Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition N2 - The femtosecond excited-state dynamics following resonant photoexcitation enable the selective deformation of N-H and N-C chemical bonds in 2-thiopyridone in aqueous solution with optical or X-ray pulses. In combination with multiconfigurational quantum-chemical calculations, the orbital-specific electronic structure and its ultrafast dynamics accessed with resonant inelastic X-ray scattering at the N 1s level using synchrotron radiation and the soft X-ray free-electron laser LCLS provide direct evidence for this controlled photoinduced molecular deformation and its ultrashort time-scale. KW - nitrogen KW - photochemistry KW - protonation KW - RIXS (resonant inelastic X-ray scattering) KW - selective bond cleavage Y1 - 2017 U6 - https://doi.org/10.1002/anie.201700239 SN - 1433-7851 SN - 1521-3773 VL - 56 SP - 6088 EP - 6092 PB - Wiley-VCH CY - Weinheim ER - TY - THES A1 - Michalczyk, Anna T1 - Modelling of nitrogen cycles in intensive winter wheat–summer maize double cropping systems in the North China Plain T1 - Modellierung von Stickstoffkreisläufen in intensiven Winterweizen–Sommermais-Doppelfruchtfolgen in der Nordchinesischen Tiefebene BT - site specific optimisation of nitrogen fertilisation with regard to nitrogen losses, water protection, productivity and regionalisation N2 - The North China Plain (NCP) is one of the most productive and intensive agricultural regions in China. High doses of mineral nitrogen (N) fertiliser, often combined with flood irrigation, are applied, resulting in N surplus, groundwater depletion and environmental pollution. The objectives of this thesis were to use the HERMES model to simulate the N cycle in winter wheat (Triticum aestivum L.)–summer maize (Zea mays L.) double crop rotations and show the performance of the HERMES model, of the new ammonia volatilisation sub-module and of the new nitrification inhibition tool in the NCP. Further objectives were to assess the models potential to save N and water on plot and county scale, as well as on short and long-term. Additionally, improved management strategies with the help of a model-based nitrogen fertiliser recommendation (NFR) and adapted irrigation, should be found. Results showed that the HERMES model performed well under growing conditions of the NCP and was able to describe the relevant processes related to soil–plant interactions concerning N and water during a 2.5 year field experiment. No differences in grain yield between the real-time model-based NFR and the other treatments of the experiments on plot scale in Quzhou County could be found. Simulations with increasing amounts of irrigation resulted in significantly higher N leaching, higher N requirements of the NFR and reduced yields. Thus, conventional flood irrigation as currently practised by the farmers bears great uncertainties and exact irrigation amounts should be known for future simulation studies. In the best-practice scenario simulation on plot-scale, N input and N leaching, but also irrigation water could be reduced strongly within 2 years. Thus, the model-based NFR in combination with adapted irrigation had the highest potential to reduce nitrate leaching, compared to farmers practice and mineral N (Nmin)-reduced treatments. Also the calibrated and validated ammonia volatilisation sub-module of the HERMES model worked well under the climatic and soil conditions of northern China. Simple ammonia volatilisation approaches gave also satisfying results compared to process-oriented approaches. During the simulation with Ammonium sulphate Nitrate with nitrification inhibitor (ASNDMPP) ammonia volatilisation was higher than in the simulation without nitrification inhibitor, while the result for nitrate leaching was the opposite. Although nitrification worked well in the model, nitrification-born nitrous oxide emissions should be considered in future. Results of the simulated annual long-term (31 years) N losses in whole Quzhou County in Hebei Province were 296.8 kg N ha−1 under common farmers practice treatment and 101.7 kg N ha−1 under optimised treatment including NFR and automated irrigation (OPTai). Spatial differences in simulated N losses throughout Quzhou County, could only be found due to different N inputs. Simulations of an optimised treatment, could save on average more than 260 kg N ha−1a−1 from fertiliser input and 190 kg N ha−1a−1 from N losses and around 115.7 mm a−1 of water, compared to farmers practice. These long-term simulation results showed lower N and water saving potential, compared to short-term simulations and underline the necessity of long-term simulations to overcome the effect of high initial N stocks in soil. Additionally, the OPTai worked best on clay loam soil except for a high simulated denitrification loss, while the simulations using farmers practice irrigation could not match the actual water needs resulting in yield decline, especially for winter wheat. Thus, a precise adaption of management to actual weather conditions and plant growth needs is necessary for future simulations. However, the optimised treatments did not seem to be able to maintain the soil organic matter pools, even with full crop residue input. Extra organic inputs seem to be required to maintain soil quality in the optimised treatments. HERMES is a relatively simple model, with regard to data input requirements, to simulate the N cycle. It can offer interpretation of management options on plot, on county and regional scale for extension and research staff. Also in combination with other N and water saving methods the model promises to be a useful tool. N2 - Die Nordchinesische Tiefebene (NCP) ist eine der produktivsten und intensivsten Agrarregionen Chinas. Große Düngermengen an mineralischem Stickstoff (N) und der oft in Kombination genutzten Überflutungsbewässerung führen zu Stickstoffüberflüssen, Grundwasserabsenkung und Umweltverschmutzung. Ziel dieser Arbeit war die Simulation des N-Kreislaufes in Winterweizen (Triticum aestivum L.)–Sommermais (Zea mays L.) -Doppelfruchtfolgen mit dem HERMES Modell. Weitere Ziele waren ein Test der Modellgüte, sowie das Potential des Modells aufzuzeigen, N und Wasser mit Hilfe einer modellbasierten N-Düngeempfehlung (NFR) und angepassten Bewässerungsstrategien einzusparen. Dies erfolgte auf Schlag- und Countyebene wie auch in Kurzzeit- und in Langzeitsimulationen, um verbesserte Managementstrategien für Quzhou-County in der Hebei-Provinz zu finden. Die Ergebnisse zeigten, dass das HERMES Modell gut unter den Wachstumsbedingungen der NCP funktioniert und alle relevanten Boden-Pflanze-Interaktionen während der Versuchszeit von 2,5 Jahren in Bezug auf N und Wasser beschreiben konnte. Es konnten keine Ertragsunterschiede zwischen Echtzeit modellbasierter NFR und anderen Behandlungen auf Schlagebene in Quzhou-County festgestellt werden. Simulationen mit steigenden Bewässerungsgaben ergaben signifikant höheren N-Austrag, höheren N-Bedarf der NFR und reduzierte Erträge. Daher birgt die konventionelle Überflutungsbewässerung, wie sie derzeit von den Landwirten praktiziert wird, große Unsicherheiten und genaue Bewässerungsmengen sollten für zukünftige Simulationsstudien bekannt sein. In der optimierten („best-practice“) Szenariosimulation auf Schlagebene konnte insbesondere die N-Düngung und der N-Austrag, aber auch die Bewässerung innerhalb 2 Jahre stark gesenkt werden. Daher hat die modellbasierte NFR in Kombination mit angepasster Bewässerung, im Gegensatz zu konventioneller und mineralischen N (Nmin)-reduzierter Behandlung, das höchste Potential Nitratauswaschung zu reduzieren. Auch das kalibrierte und validierte Ammoniak-Verflüchtigungs-modul des HERMES Modells funktionierte gut unter den Klima- und Bodenverhältnissen in Nordchina. Die zwei einfacheren Ammoniak-Verflüchtigungsansätze erreichten auch gute Ergebnisse, während die zwei prozessorientierten Ansätze Umwelteinflüsse besser darstellen konnten. In der Simulation mit der Ammonsulfatsalpeter-Düngung mit Nitrifikationsinhibitor (ASNDMPP) war die Ammoniakverflüchtigung höher als in der Simulation ohne Nitrifikationshemmer, während das Ergebnis für Nitratauswaschung umgekehrt war. Obwohl der Nitrifikationsansatz gut funktionierte, sollten von der Nitrifikation stammende Lachgasemissionen in Zukunft im Modell berücksichtigt werden. Im Jahresdurchschnitt lagen die simulierten Langzeit (31 Jahre) N-Verluste für eine Weizen-Mais-Doppelfruchtfolge im ganzen Quzhou-County bei 296,8 kg N ha−1 unter konventioneller Düngung und bei 101,7 kg N ha−1 unter optimierter Düngung inklusive NFR and automatischer Bewässerung (OPTai). Räumliche Unterschiede von simulierten N-Verlusten in Quzhou-County konnten nur aufgrund von unterschiedlichen N-Düngemengen gefunden werden. Simulationen einer optimierten Behandlung konnten im Durchschnitt mehr als 260 kg N ha−1a−1 an N-Düngung und 190 kg N ha−1a−1 an N-Verlusten und 115,7 mm a−1 an Wasser, im Vergleich zur konventionellen Behandlung, einsparen. Im Vergleich zu den Kurzzeitsimulationen ist es ein niedrigeres N- und Wasserreduktionspotential und unterstreicht die Notwendigkeit von Langzeitsimulationen um den Effekt von hohen Anfangs Nmin-Gehalten im Boden zu berücksichtigen. Zudem kommt, dass auf tonigem Lehm Simulationen mit konventioneller Bewässerung nicht den aktuellen Wasserbedarf decken konnten, welches zu Ertragseinbußen insbesondere für Winterweizen führte. Die OPTai Behandlung funktionierte bis auf hohe simulierte Denitrifikationsverluste auf diesem Standort am besten. Daher ist dort für zukünftige Simulationen ein an aktuelle Wetterverhältnisse und Pflanzenwachstumsbedürfnisse angepasstes Management von N und Wasser nötig. Trotzdem schienen die optimierten Behandlungen, trotz voller Strohrückgabe, die organische Bodensubstanz nicht zu erhalten. Zur Sicherung der Bodenfruchtbarkeit in den optimierten Behandlungen scheinen zusätzliche organische Düngergaben wahrscheinlich notwendig zu sein. HERMES ist ein relativ einfaches Modell, im Hinblick auf die Anforderungen an die Eingangsdaten, um den Stickstoffkreislauf zu simulieren. Es ermöglicht, Managementoptionen für Berater und Wissenschaftler auf Schlag-, County- und Regionalebene anzuwenden. Auch in Kombination mit anderen N- und Wasser-Einsparmethoden verspricht das Modell ein nützliches Instrument zu sein. KW - nitrogen KW - Stickstoff KW - simulation KW - Simulation KW - China KW - China Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-444213 ER - TY - GEN A1 - Wilske, Burkhard A1 - Eccard, Jana A1 - Zistl-Schlingmann, Marcus A1 - Hohmann, Maximilian A1 - Methler, Annabel A1 - Herde, Antje A1 - Liesenjohann, Thilo A1 - Dannenmann, Michael A1 - Butterbach-Bahl, Klaus A1 - Breuer, Lutz T1 - Effects of short term bioturbation by common voles on biogeochemical soil variables T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Bioturbation contributes to soil formation and ecosystem functioning. With respect to the active transport of matter by voles, bioturbation may be considered as a very dynamic process among those shaping soil formation and biogeochemistry. The present study aimed at characterizing and quantifying the effects of bioturbation by voles on soil water relations and carbon and nitrogen stocks. Bioturbation effects were examined based on a field set up in a luvic arenosol comprising of eight 50 x 50 m enclosures with greatly different numbers of common vole (Microtus arvalis L., ca. 35-150 individuals ha(-1) mth(-1)). Eleven key soil variables were analyzed: bulk density, infiltration rate, saturated hydraulic conductivity, water holding capacity, contents of soil organic carbon (SOC) and total nitrogen (N), CO2 emission potential, C/N ratio, the stable isotopic signatures of C-13 and N-15, and pH. The highest vole densities were hypothesized to cause significant changes in some variables within 21 months. Results showed that land history had still a major influence, as eight key variables displayed an additional or sole influence of topography. However, the delta N-15 at depths of 10-20 and 20-30 cm decreased and increased with increasing vole numbers, respectively. Also the CO2 emission potential from soil collected at a depth of 15-30 cm decreased and the C/N ratio at 5-10 cm depth narrowed with increasing vole numbers. These variables indicated the first influence of voles on the respective mineralization processes in some soil layers. Tendencies of vole activity homogenizing SOC and N contents across layers were not significant. The results of the other seven key variables did not confirm significant effects of voles. Thus overall, we found mainly a first response of variables that are indicative for changes in biogeochemical dynamics but not yet of those representing changes in pools. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 499 KW - small mammalian herbivores KW - Microtus agrestis KW - pocket gophers KW - field voles KW - ecosystem services KW - functional traits KW - organic-carbon KW - nitrogen KW - population KW - landscape Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-408375 SN - 1866-8372 IS - 499 ER - TY - JOUR A1 - Leuschner, Christoph A1 - Wulf, Monika A1 - Baeuchler, Patricia A1 - Hertel, Dietrich T1 - Forest continuity as a key determinant of soil carbon and nutrient storage in beech forests on sandy soils in Northern Germany JF - Ecosystems N2 - Forest (or tree) age has been identified as an important determinant of the carbon (C) storage potential of forest soils. A large part of Central Europe's current forested area was affected by land use change with long periods of cultivation in past centuries suggesting that the organic C stocks in the soil (SOC) under recent forest may partly be legacies of the past and that stand age effects have to be distinguished from forest continuity effects (that is, the time since re-afforestation). We examined the influence of mean tree age and forest continuity on the SOC pool and the stores of total N and available P, Ca, Mg, and K in the soil (mineral soil and organic layer) across a sample of 14 beech (Fagus sylvatica) forests on sandy soil with variable tree age (23-189 years) and forest continuity (50-year-old afforestation to ancient ('permanent') forest, that is, > 230 years of proven continuity). Ancient beech forests (> 230 years of continuity) stored on average 47 and 44% more organic C and total N in the soil than recent beech afforestation (50-128 years of continuity). Contrary to expectation, we found large and significant C and N pool differences between the forest categories in the mineral soil but not in the organic layer indicating that decade- or century-long cultivation has reduced the subsoil C and nutrient stores while the organic layer element pools have approached a new equilibrium after only 50-128 years. PCA and correlation analyses suggest that forest continuity cannot be ignored when trying to understand the variation in soil C stocks between different stands. Forest clearing, subsequent cultivation, and eventual re-afforestation with beech resulted in similar relative stock reductions of C and N and, thus, no change in soil C/N ratio. We conclude that the continuity of forest cover, which may or may not be related to tree age, is a key determinant of the soil C and nutrient stores of beech forests in the old cultural landscape of Central Europe. KW - afforestation KW - ancient forests KW - available phosphorus KW - calcium KW - Fagus sylvatica KW - forest clear-cut KW - magnesium KW - nitrogen KW - potassium KW - sandy soil Y1 - 2014 U6 - https://doi.org/10.1007/s10021-013-9738-0 SN - 1432-9840 SN - 1435-0629 VL - 17 IS - 3 SP - 497 EP - 511 PB - Springer CY - New York ER -