Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2011
Authors
Michael W.I. Schmidt Margaret S. Torn Samuel Abiven Thorsten Dittmar Georg Guggenberger Ivan A. Janssens Markus Kleber Ingrid Kögel-Knabner Johannes Lehmann David A.C. Manning Paolo Nannipieri Daniel Rasse Steve Weiner Susan E. TrumboreAbstract
Globally, soil organic matter (SOM) contains more than three times as much carbon as either the atmosphere or terrestrial vegetation. Yet it remains largely unknown why some SOM persists for millennia whereas other SOM decomposes readily—and this limits our ability to predict how soils will respond to climate change. Recent analytical and experimental advances have demonstrated that molecular structure alone does not control SOM stability: in fact, environmental and biological controls predominate. Here we propose ways to include this understanding in a new generation of experiments and soil carbon models, thereby improving predictions of the SOM response to global warming.
Abstract
No abstract has been registered
Authors
Jihong Liu ClarkeAbstract
No abstract has been registered
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No abstract has been registered
Authors
Nicholas Clarke Richard Fischer Wim De Vries Lars Lundin Dario Papale Timo Vesala Päivi Merilä Giorgio Matteucci Michael Mirtl David Simpson Elena PaolettiAbstract
Data from existing monitoring programmes such as ICP Forests, ICP Integrated Monitoring and EMEP, as well as from large-scale international projects such as CarboEurope IP and NitroEurope, can be used to answer questions about the impacts of air pollution and climate change on forest ecosystems and the feedbacks of forest to climate. However, for full use to be made of the available data, a number of questions need to be answered related to the availability, accessibility, quality and comparability of the data. For example, how can these databases be accessed, e.g., freely, over the internet, on request, by authorisation? How should intellectual property rights be protected, while improving access to data? What possibilities exist for harmonisation? Which quality assurance/quality control (QA/QC) procedures have been used and for how long? These and other relevant questions are discussed.
Authors
Hans Dieter Nagel Thomas Scheuschner Angela Schlutow Oliver Granke Nicholas Clarke Richard FischerAbstract
Based on intensive forest monitoring data, critical loads for acidification and eutrophication as well as their exceeedances were modelled for 107 Level II plots using the simple mass balance approach. Dynamic modelling using the VSD model was carried out for 77 plots using different deposition scenarios.Results show widespread soil acidification in the year 1980 with nearly 60% of the plots affected by critical load exceedances. A continued positive future development until 2020 is clearly visible, leading to full protection at least under the most ambitious deposition scenario.Critical loads for nutrient nitrogen were exceeded on 60% of the plots in 1980 and continue to be so in 2020 on between 10 and 30% of the plots depending on the scenario. Dynamic modelling shows that soil solution pH can recover to pre-industrial values but that over the all the 77 plots the C:N ratio shows a continuous decrease until 2050.A comparison with to measured solid soil pH from large scale plots confirms recovery for acidified soils until 2008 but shows increased acidification on soils with pH above 4.0. and points to the fact that full recovery from acidification will take decades. Decreasing C:N and continued exceedance of critical loads for nutrient nitrogen point to soil eutrophication as a major and continued area of concern.
Abstract
We used two datasets of 14C analyses of archived soil samples to study carbon turnover in O horizons from spruce dominated old-growth stands on well-drained podzols in Scandinavia. The main data set was obtained from archived samples from the National Forest Soil Inventory in Sweden and represents a climatic gradient in temperature. Composite samples from 1966, 1972, 1983 and 2000 from four different regions in a latitude gradient ranging from 57 to 67º N were analysed for 14C content. Along this gradient the C stock in the O horizon ranges from 2.1 kg m-2 in the north to 3.7 kg m-2 in the southwest. The other data set contains 14C analyses from 1986, 1987, 1991, 1996 and 2004 from the O horizons in Birkenes, Norway. Mean residence times (MRT) were calculated using a two compartment model, with a litter decomposition compartment using mass loss data from the literature for the threefirst years of decomposition and a humus decomposition compartment with a fitted constant turnover rate. We hypothesized that the climatic gradient would result in different C turnover in different parts of the country between northern and southern Sweden. The use of archived soil samples was very valuable for constraining the MRT calculations, which showed that there were differences between the regions. Longest MRT was found in the northernmost region (41 years), with decreasing residence times through the middle (36 years) and central Sweden (28 years), then again increasing in the southwestern region (40 years). The size of the soil organic carbon (SOC) pool in the O horizon was mainly related to differences in litter input and to a lesser degree to MRT. Because N deposition leads both to larger litter input and to longer MRT, we suggest that N deposition contributes significantly to the latitudinal SOC gradient in Scandinavia, with approximately twice as much SOC in the O horizon in the south compared to the north. The data from Birkenes was in good agreement with the Swedish dataset with MRT estimated to 34 years.
Abstract
We used two datasets of 14C analyses of archived soil samples to study carbon turnover in O horizons from spruce dominated old-growth stands on well-drained podsols in Scandinavia. The main data set was obtained from archived samples from the National Forest Soil Inventory in Sweden and represents a climatic gradient in temperature. Composite samples from 1966, 1972, 1983 and 2000 from four different regions in a latitude gradient ranging from 57 to 67oN were analysed for 14C content. Along this gradient the C stock in the O horizon ranges from 2.1 kg m-2 in the north to 3.7 kg m-2 in the southwest. The other data set contains 14C analyses from 1986, 1987, 1991, 1996 and 2004 from the O horizons in Birkenes, Norway. Mean residence times (MRT) were calculated using a two compartment model, with a litter decomposition compartment using mass loss data from the literature for the three first years of decomposition and a humus decomposition compartment with a fitted constant turnover rate. We hypothesized that the climatic gradient would result in different C turnover in different parts of the country between northern and southern Sweden. The use of archived soil samples was very valuable for constraining the MRT calculations, which showed that there were differences between the regions. Longest MRT was found in the northernmost region (41 years), with decreasing residence times through the middle (36 years) and central Sweden (28 years), then again increasing in the southwestern region (40 years). The size of the soil organic carbon (SOC) pool in the O horizon was mainly related to differences in litter input and to a lesser degree to MRT. Because N deposition leads both to larger litter input and to longer MRT, we suggest that N deposition contributes significantly to the latitudinal SOC gradient in Scandinavia, with approximately twice as much SOC in the O horizon in the south compared to the north. The data from Birkenes was in good agreement with the Swedish dataset with MRT estimated to 34 years.
Abstract
The main task of the C1-Dep-22(SI) action was to compare national throughfall collectors with a harmonized collector which was designed according to the requirements of the WMO. The action spread onthe took place in very different climate zones and vegetation, and included a very different types of national collectors with different sampling procedures. The number of harmonized throughfall collectors was 30 for all participants. The spatial arrangement in the plot, sampling times, sampling and cleaning procedures, bulking of the subsamples and chemical analysis procedures were in all cases the national procedures. The time when the precipitation was in the form of snow was excluded from the sampling periods. The associated beneficiaries reported the amounts of the precipitation per collector and the results from chemical analysis per pooled sample. The measured quantities were compared for different types of forest or main tree species. The deviations between collectors were lower in the plots with the broadleaf trees than in the plots with conifers as the main tree species. The median deviations for conifers and for broadleaves trees is not significantly different from zero. Except in a few cases, a good agreement in the amount of precipitation was found between the national and harmonized collectors for both throughfall and bulk precipitation. In a few incidents this was not the case but we assume that where this was not the case, this was due to happened in extreme weather conditions e. g. heavy storms. Also good agreement was also found within for the chemical composition of the solutions, gathered with different types of collectors. Again, there were some deviations limited to on single occasions. It was found that the harmonized collectors were attractive to birds and thus a bird ring is a must in this (white) -coloured version of the collector. Chemical analysis (chemical composition) together with the collected amount of the solution depends on give the total deposition values. It was made a close up to the deposition values of ammonium-nitrogen, nitrate-nitrogen and sulphate-sulphur were compared in detail. For ammonium-nitrogen no bigger difference was found for the one-year deposition values except in one case what which turned out to be almost certainly a consequence of birds activity. Differences in all other cases were no more than 0.3 g m-2 yr-1. For nitrate-nitrogen smaller deviations were found but in none of the case was the difference was in total annual deposition higher than 0.3 g m-2 yr-1. For sulphate-sulphur good agreement was found for all associated beneficiaries except two. One of the Possible reasons could be in the difference of in the ability in collecting dry deposition and/or the total area which contributes to the capturing area for dry deposition. Despite their heterogeneity and some unlack of adaptation for representative sampling at the plot scale, the national devices for throughfall collection gave comparable results infor throughfall deposition to the harmonized, optimal collectors. In conclusion national throughfall collection devices can be maintained to ensure the continuity of the time series in deposition monitoring. And to improve the harmonized collector even more, problems with the possible blockages of the tube at the bottom of the funnel because of debris should be solved.
Abstract
No abstract has been registered