Teresa Gómez de la Bárcena

Forsker

(+47) 405 56 025
teresa.barcena@nibio.no

Sted
Ås - Bygg O43

Besøksadresse
Oluf Thesens vei 43, 1433 Ås (Varelevering: Elizabeth Stephansens vei 23)

Sammendrag

Denne rapporten beskriver alle prosesser som er utarbeidet innenfor datafangst, dataforvaltning, bearbeiding og analyse samt formidling i implementeringsfasen av et nytt jordovervåkingsprogram for jordbruksjord i Norge. Rapporten inneholder detaljerte planer for hvordan jordinformasjon fra ulike indikatorer skal innhentes, analyseres og bearbeides slik at tilstand og endring i jordsmonnet kan overvåkes. Programmet vil danne grunnlaget for landsdekkende jordinformasjon som muliggjør en vurdering av jordsmonnets status og endring for de fem truslene man har identifisert for norsk jordbruksjord: erosjon, jordpakking, tap av organisk materiale, tap av jordbiodiversitet og forurensning.

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Sammendrag

In Norway, cover crops were introduced to prevent loss of nitrogen and phosphorous from fields to waterways. Today, cover crops are also used to restore soil organic matter and improve soil health. Yet, the direction and magnitude of these effects are variable, and little is known about the persistence of the C derived from the cover crops in the soil. In the CAPTURE project, we evaluated the soil C sequestration potential from different cover crops used in the main cereal production areas in Norway. To do so, we used pulse labelling with 13C (CO2) to label four different cover crop species Italian ryegrass, phacelia, oilseed radish and summer vetch through their growing period. Cover crops were grown in a monoculture to enable the labelling. The results of the first year of the experiment show that cover crops produced 10- 14 Mg ha-1 above ground biomass, corresponding to 4-6 Mg C ha-1. At the end of the growing season, 3-5% of cover crop C was found in the soil particulate organic matter (POM) fraction and 2-4% in the soil mineral organic matter fraction (MAOM). In the following years, the fate of C derived from the cover crops in the soil will be determined. Furthermore, the soil C sequestration of the different cover crops will be scaled to barley plots in the same experiment, to which cover crops had been undersown in spring or summer. In these plots, N2O emissions have been measured through the whole year. The greenhouse gas trade-offs of cover crops in Norwegian cereal production will be estimated.

Sammendrag

Denne publikasjonen presenterer en ny metodikk for estimering av endringer i lageret av jordkarbon som følge av arealbruksendringer på mineraljord. Metodikken er utviklet for bruk i den nasjonale rapporteringen av arealbrukssektoren under FNs klimakonvensjon. Metodikken baserer seg på den enkleste tilnærming i følge IPCC sine retningslinjer, en såkaldt Tier 1. Tier 1 metodikken baseres i stor grad på standardverdier fra retningslinjene (IPCC default), men trenger en kopling mot nasjonal arealinformasjon. Denne koplingen beskrives i rapporten. Metodikken tar utgangspunkt i standardverdier for lageret av jordkarbon (SOCREF). Disse er basert på jordtype-grupperinger og klimasone som stammer fra en verdensdekkende jorddatabase. Endringer i jordkarbon etter arealbruksendring estimeres ved hjelp av SOCREF i kombinasjon med et sett faktorer (også standardverdier) som er arealbruksavhengige. Metodikken legger til grunn at endringer i jordkarbon skjer lineært over 20 år (ifølge 2006 IPCC Guidelines). Grunnleggende informasjon for å kunne kople standardverdier mot arealer på en konsistent måte er stort sett manglende for Norge på nasjonal skala. Rapporten gir derfor detaljert informasjon om de datakildene som har vært brukt til å kunne definere hvilke standariserte verdier som tilhører et bestemt areal i overgang....

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Sammendrag

The role of soils in the global carbon cycle and in reducing GHG emissions from agriculture has been increasingly acknowledged. The ‘4 per 1000’ (4p1000) initiative has become a prominent action plan for climate change mitigation and achieve food security through an annual increase in soil organic carbon (SOC) stocks by 0.4%, (i.e. 4‰ per year). However, the feasibility of the 4p1000 scenario and, more generally, the capacity of individual countries to implement soil carbon sequestration (SCS) measures remain highly uncertain. Here, we evaluated country-specific SCS potentials of agricultural land for 24 countries in Europe. Based on a detailed survey of available literature, we estimate that between 0.1% and 27% of the agricultural greenhouse gas (GHG) emissions can potentially be compensated by SCS annually within the next decades. Measures varied widely across countries, indicating differences in country-specific environmental conditions and agricultural practices. None of the countries' SCS potential reached the aspirational goal of the 4p1000 initiative, suggesting that in order to achieve this goal, a wider range of measures and implementation pathways need to be explored. Yet, SCS potentials exceeded those from previous pan-European modelling scenarios, underpinning the general need to include national/regional knowledge and expertise to improve estimates of SCS potentials. The complexity of the chosen SCS measurement approaches between countries ranked from tier 1 to tier 3 and included the effect of different controlling factors, suggesting that methodological improvements and standardization of SCS accounting are urgently required. Standardization should include the assessment of key controlling factors such as realistic areas, technical and practical feasibility, trade-offs with other GHG and climate change. Our analysis suggests that country-specific knowledge and SCS estimates together with improved data sharing and harmonization are crucial to better quantify the role of soils in offsetting anthropogenic GHG emissions at global level.

Sammendrag

To increase the annual uptake of CO2 as well as the long-term storage of carbon (C) in forests, the Norwegian government consider large-scale replacements of native, deciduous forests with faster-growing species like Norway spruce. To assess the effects of tree species change on ecosystem C and nitrogen (N) stocks and soil chemistry, we used a paired plot approach including stands of native downy birch and planted 45 – 60-year-old Norway spruce. The birch stands were used as reference for the assessment of differences following the tree species change. We found significantly higher C and N stocks in living tree biomass in the spruce stands, whereas no significant differences were found for dead wood. The cover of understory species groups, and the C and N stocks of the aboveground understory vegetation was significantly higher in the birch stands. The tree species change did not affect the soil organic carbon (SOC) stock down to 1 m soil depth; however, the significantly higher stock in the forest floor of the spruce stands suggested a re-distribution of SOC within the profile. There was a significant positive correlation between the SOC stock down to 30 cm soil depth and the total ecosystem C stock for the birch stands, and a negative correlation for the spruce stands. Significant effects of tree species change were found for C and N concentrations, C/N, exchangeable acidity, base saturation, and exchangeable Ca, K, Mg, Na, S, and Fe in the organic horizon or the upper mineral soil layer. The total ecosystem C stock ranged between 197 and 277 Mg ha-1 for the birch stands, and 297 and 387 Mg ha-1 for the spruce stands. The ecosystem C accumulation varied between 32 and 142 Mg ha-1 over the past 45-60 years, whereas the net ecosystem C capture was considerably lower and potentially negative. Our results suggest that the potential to meet the governments’ targets to increase C sequestration depend on the C debt incurred from the removed birch stands, the rotation length, and potentially also the susceptibility of the different stand types to future risk factors related to climate change.

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Sammendrag

The use of biomass from forest harvesting residues or stumps for bioenergy has been increasing in the northern European region in the last decade. The present analysis is a regional review from Nordic and UK coniferous forests, focusing on the effects of whole-tree harvesting (WTH) or whole-tree thinning (WTT) and of WTH followed by stump removal (WTH + S) on the forest floor and mineral soil, and includes a wider array of chemistry data than other existing meta-analyses. All intensified treaments led to significant decreases of soil organic carbon (SOC) stock and total N stock in the forest floor (FF), but relative responses compared with stem-only harvesting were less consistent in the topsoil (TS) and no effects were detected in the subsoil (SS). Exchangeable P was reduced in the FF and TS both after WTT and WTH, but significant changes in exchangeable Ca, K, Mg and Zn depended on soil layer and treatment. WTH significantly lowered pH and base saturation (BS) in the FF, but without apparent changes in cation exchange capacity (CEC). The only significant WTH-effects in the SS were reductions in CEC and BS. Spruce- and pine-dominated stands had comparable negative relative responses in the FF for most elements measured except Mg and for pH. Relative responses to intensified harvesting scaled positively with growing season temperature and precipitation for most variables, most strongly in FF, less in the TS, but almost never in the SS, but were negative for P and Al. The greater reduction in FF and TS for soil organic carbon after intensive harvesting decreased with time and meta-regression models predicted an average duration of 20–30 years, while many other chemical parameters generally showed linear effects for 30–45 years after intensified harvesting. Exchangeable acidity (EA), BS and pH all showed the reversed effect with time, i.e. an initial increase and then gradual decrease over 24–45 years. The subsoil never showed a significant temporal effect. Our results generally support greater reductions in nutrient concentrations, SOC and total N in forest soil after WTH compared with SOH in northern temperate and boreal forest ecosystems.

Sammendrag

Karboninnholdet i jord har gått ned i store deler av verden. Også i Norge. For landbruket er det derfor viktig med driftsmåter som øker lagringen av karbon i jordsmonn. Gras til eng og beite er et effektivt CO2-lager, men jordart og driftsmåte kan påvirke lagringsevnen.

Sammendrag

Deliverable 2.5. This report contributes to the EJP SOIL roadmap for climate-smart sustainable agricultural soil management and research by identifying current policy targets and realizations and setting soil service aspirational goals by 2050 at the regional/national (Chapter 2) and European scale (Chapter 3). At both scales, the report is based on a desk study of current agricultural soil related policies, followed by a stakeholder consultation. Twenty countries/regions have contributed to the regional/national analyses and 347 different stakeholders have provided their views on soil policy. The policy analysis demonstrates that large differences exist between the number of policy targets per soil challenge. In general, the soil challenge ‘Maintaining/increasing soil organic carbon’ can be considered as the most important soil challenge taking into account both the policies of the participating countries and of the EU level. This soil challenge not only has (one of) the largest share(s) of quantitative and qualitative targets, but also has a large share of the targets for which an indicator and monitoring is in progress or existing. At the EU level, ‘Avoiding contamination’ is also particularly high addressed in policy documents. In the participating countries, other very important soil challenges in policy are ‘Enhance nutrient retention/use efficiency’, ‘Avoid soil erosion’ and ‘Avoid soil contamination’. These soil challenges comprise a large share of soil- and agricultural soil specific targets. However, despite the large number of policy targets, identified by the participating EJP SOIL countries, there is still a shared need for appropriate clear (quantified) policy targets with a specific time horizon, well-defined indicators and a monitoring systems. Similar results are found at the EU level. Policy targets addressing soil challenges are mostly not expressed in quantitative terms and indicators for monitoring policy targets with references to soil challenges were identified for less than half of the cases. From the stakeholder consultations, it becomes clear that for all soil challenges there is still a way to go before future aspirational goals will be met. Generally, when averaging between all countries, the gap between current policy targets and realizations is for most soil challenges considered between large and halfway in reaching the current policy targets and for most soil challenges current policy targets are regarded almost- to- far from being futureproof. In the prioritization of soil challenges, stakeholders at the regional/country and European level, clearly marked maintaining/increasing SOC as the most relevant soil challenge in the upcoming decades. The stakeholders explain the key role of maintaining/increasing soil organic carbon through the multiple interactions with other soil challenges and for climate change mitigation. At the EU level, the second highest ranked prioritization is soil sealing, due to its irreversible nature. This is, however, not reflected at the country level, potentially due to a misinterpretation of soil sealing as compaction by part of the stakeholders. At the country level, enhancing soil nutrient retention/use efficiency was ranked 2nd in the prioritization exercise. Generally, there is an urgency for policy updates, because the current policy is considered unable to tackle the prominent soil challenges. In the report, also the soil related management practices to achieve the aspirational goals have been identified, both in the policy analysis and in the stakeholder consultation. The most prominent differences between policy and stakeholders, is in the emphasis on the use of buffer strips and small landscape elements in policy, while measures in this category are less highly ranked by the stakeholders. On the other hand, conservation agriculture, agro-ecological farming, precision agriculture, incorporation ........

Sammendrag

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Sammendrag

Deliverable 2.3. This synthesis identifies the available knowledge of achievable carbon sequestration in mineral soils and GHGs mitigation in organic soils in agricultural land, including pasture/grassland across Europe. The inventory of past and current studies on carbon sequestration and GHGs mitigation measures in agricultural soils and the methodology used for the assessment were considered from 25 Member states (MS) across Europe. The stocktake shows that availability of datasets concerning soil carbon sequestration (SCS) is variable among Europe. While northern Europe and central Europe is relatively well studied, there is a lack of studies comprising parts of Southern, Southeaster and Western Europe. Further, it can be concluded that at present country based knowledge and engagement is still poor; very few countries have an idea on their national-wide achievable carbon sequestration potential. The presented national SCS potentials (MS n=13) do however point towards important contributions to mitigate climate change by covering considerable shares of national greenhouse gas emissions from the agricultural sector in the range of 0.1-27 %, underpinning the importance of further investigations. In contrast to mineral soils, effective mitigation measures for organic soils while maintaining industrial agricultural production are still in its infancy. Very few mitigation options exist to mitigate GHG emissions without compromising agricultural production. Most GHG mitigation practices reported by the MS involve the restoration of organic soils, which means a complete abandonment of land from any agricultural use. Only one contribution (NL) reports possible mitigation potentials, which are based on specific water management measures (water level fixation). Nevertheless, there is an increasing awareness of the need of mitigation measures reflected by the several ongoing research projects on peatland management.

Sammendrag

Perennial versus short term (<3 years) grass vegetation cover is likely to have considerable differences in root density and thus carbon (C) inputs to soil. Carbon inputs are important to maintain soil organic carbon (SOC) and may even increase it. In Norway and Scandinavia, the SOC content in soil is often higher than in other parts of Europe, due to the cold climate and high precipitation (i.e. slower turnover rates for soil organic matter) and a dominance of animal production systems with a large amount of grassland. Here we aimed to evaluate differences in SOC content, down to 60 cm depth, of a long-term grassland (without ploughing for decades) and a short-term grassland (frequently renewed by ploughing) under contrasting climate, soil and management conditions. Quantification of SOC was carried out on three long-term experimental sites on an extended latitude gradient in West and North Norway. The samples were taken from 4 depth increments (0-5, 5-20, 20-40 and 40-60 cm) in treatments that have not been ploughed for at least 43 years, and in treatments that were ploughed every third year until 2011. Preliminary results suggest that there is no significant difference in SOC storage down to 60 cm between long-term and short-term grasslands.

Sammendrag

Cultivated organic soils account for ~7% of Norway’s agricultural land area, and they are estimated to be a significant source of greenhouse gas (GHG) emissions. The project ‘Climate smart management practices on Norwegian organic soils’ (MYR), commissioned by the Research Council of Norway (decision no. 281109), aims to evaluate GHG (e.g. carbon dioxide, methane and nitrous oxide) emissions and impacts on biomass productivity from three land use types (cultivated, abandoned and restored) on organic soils. At the cultivated sites, impacts of drainage depth and management intensity will be measured. We established experimental sites in Norway covering a broad range of climate and management regimes, which will produce observational data in high spatiotemporal resolution during 2019-2022. Using state-of-the-art modelling techniques, MYR aims to predict the potential GHG mitigation under different scenarios (e.g. different water table depth, management practices and climate pattern). Four models (BASGRA, DNDC, Coup and ECOSSE) will be further developed according to the physical/chemical properties of peat soil and then used independently in simulating biogeochemical processes and biomass dynamics in the different land uses. Robust parameterization schemes for each model to improve the predictive accuracy will be derived from a new dataset collected from multiple experimental sites in the Nordic region. Thereafter, the models will be used in the regional simulation to present the spatial heterogeneity in large scale. Eventually, a multi-model ensemble prediction will be carried out to provide scenario analyses by 2030 and 2050. By integrating experimental results and modelling, the project aims at generating useful information for recommendations on environment-friendly use of Norwegian peatlands.

Sammendrag

En økning i karbonlagring i landbruksjord er angitt som et viktig klimatiltak både internasjonalt og i Norge. Tiltaket er godt begrunnet: Jorden inneholder to til tre ganger så mye karbon som atmosfæren, noe som innebærer at relative små endringer i innhold av karbon i jord kan ha betydelige effekter på CO2-innholdet i atmosfæren og det globale klimaet. Det er godt dokumentert at intensive jordbruksmetoder har ført til en reduksjon i jordkarbon og derfor ønskes det en reversering av denne trenden (dvs. økt karbonbinding i jord), som tiltak både for klima og matproduksjon. I denne rapporten er det gjort vurderinger av hvordan dette kan gjøres i Norge og hvilken klimaeffekt som kan oppnås...

Sammendrag

Cultivated organic soils account for ∼7% of Norway’s agricultural land area, and they are estimated to be a significant source of greenhouse gas (GHG) emissions. The project ‘Climate smart management practices on Norwegian organic soils’ (MYR), commissioned by the Research Council of Norway (decision no. 281109), aims to evaluate GHG (e.g. carbon dioxide, methane and nitrous oxide) emissions and impacts on biomass productivity from three land use types (cultivated, abandoned and restored) on organic soils. At the cultivated sites, impacts of drainage depth and management intensity will be measured. We established experimental sites in Norway covering a broad range of climate and management regimes, which will produce observational data in high spatiotemporal resolution during 2019-2021. Using state-of-the-art modelling techniques, MYR aims to predict the potential GHG mitigation under different scenarios. Four models (BASGRA, DNDC, Coup and ECOSSE) will be further developed according to the soil properties, and then used independently in simulating biogeochemical processes and biomass dynamics in the different land uses. Robust parameterization schemes for each model will be based in the observational data from the project for both soil and crop combinations. Eventually, a multi-model ensemble prediction will be carried out to provide scenario analyses by 2030 and 2050. By integrating experimental results and modelling, the project aims at generating useful information for recommendations on environment-friendly use of Norwegian peatlands.

Sammendrag

Cultivated organic soils (7-8% of Norway’s agricultural land area) are economically important sources for forage production in some regions in Norway, but they are also ‘hot spots’ for greenhouse gas (GHG) emissions. The project ‘Climate smart management practices on Norwegian organic soils’ (MYR; funded by the Research Council of Norway, decision no. 281109) will evaluate how water table management and the intensity of other management practices (i.e. tillage and fertilization intensity) affects both GHG emissions and forage’s quality & production. The overall aim of MYR is to generate useful information for recommendations on climate-friendly management of Norwegian peatlands for both policy makers and farmers. For this project, we established two experimental sites on Norwegian peatlands for grass cultivation, of which one in Northern (subarctic, continental climate) and another in Southern (temperate, coastal climate) Norway. Both sites have a water table level (WTL) gradient ranging from low to high. In order to explore the effects of management practices, controlled trials with different fertilization strategies and tillage intensity will be conducted at these sites with WTL gradients considered. Meanwhile, GHG emissions (including carbon dioxide, methane and nitrous oxide), crop-related observations (e.g. phenology, production), and hydrological conditions (e.g. soil moisture, WTL dynamics) will be monitored with high spatiotemporal resolution along the WTL gradients during 2019-2021. Besides, MYR aims at predicting potential GHG mitigation under different scenarios by using state-of-the-art modelling techniques. Four models (BASGRA, Coup, DNDC and ECOSSE), with strengths in predicting grass growth, hydrological processes, soil nitrification-denitrification and carbon decomposition, respectively, will be further developed according to the soil properties. Then these models will be used independently to simulate biogeochemical and agroecological processes in our experimental fields. Robust parameterization schemes will be based on the observational data for both soil and crop combinations. Eventually, a multi-model ensemble prediction will be carried out to provide scenario analyses by 2030 and 2050. We will couple these process-based models with optimization algorithm to explore the potential reduction in GHG emissions with consideration of production sustenance, and upscale our assessment to regional level.

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Sammendrag

Tree species change has been suggested as one of the government policies to mitigate climate change in Nor-way with the aim to increase the annual uptake of CO2 and the long-term storage of carbon (C) in forests. The strategy includes replacing native, deciduous species with fast-growing species, mainly Norway spruce. A shift in tree species is expected to affect the pools and fluxes of C in the stand as well as the microbial community. As part of the BalanC project, we assess C storage related to shift in tree species cover in western Norway and whether a corresponding shift in soil microbial communities are happening. The study aim at integrating results on soil respiration, C mineralization, soil stability, diversity of bacteria, fungi and micro-eukaryotes, soil nutrient pools, litter inputs and edaphic factors at the stand level in order to identify key drivers for changes in the soil C stocks. Fifteen paired plots of native birch and planted Norway spruce at five locations were sampled. Prelimi-nary results suggests a redistribution of C from the mineral soil to the forest floor in the spruce stands, with minor changes in the total soil C pools over the 45-60 years since the tree species change. The in situ soil respi-ration and heterothropic respiration, as well as C mineralization rates, were higher in birch than in spruce stands. Differences in C mineralization rates attenuate with depth between forest types. The microbial com-munities of the three organismal groups were all strongly structured along the vertical depth.

Sammendrag

Tindved (Hippophae ramnoides L.) er en sterkt grenet, tornet busk hjemmehørende i tempererte regioner av Europa og Asia som produserer næringsrike orange/gule frukter. Den har viktige funksjoner som næringskilde og som jordforbedrer. Fruktene inneholder høye konsentrasjoner av blant annet karbohydrater, proteiner, organiske syrer, aminosyrer og vitaminer med viktig kommersiell verdi. Tindved er en nitrogen-fikserende plante med et omfattende rotsystem og begge disse egenskaper gjører at planten blir brukt til planting i næringsfattig jord og ustabil grunn, og som pionerart i degradert jord. I Norge er bruk og produksjon av tindved fortsatt relativt nytt. Prosjektet FREMTIND har undersøkt og samlet eksisterende kunnskap om flerbruk av tindved og produksjon av frukt i Norge. Den tilgjengelige litteratur viser at tindvedplanten og fruktene har vært brukt med veldig ulike formål, fra fôr til medisinske og kosmetiske produkter, biodiesel-produksjon, m.m. I tillegg har prosjektet tatt noe analyser på høstet biomasse i et prøvefelt i Sogn med tre ulike sorter. Dette feltet produserte 1252 kg frukt per dekar i 2016, noe som tilsvarer det man produserer i andre land som Russland. Den største del av den biomassen som var høstet fantes i frukt, grener og nyskudd. Erfaringer fra Njøs Næringsutvikling AS (NNU) viser at svenske sorter som har vært prøvd i Sogn gir god avling med bare ett tilvekstår mellom hver høsting, dvs. høsting annethvert år. Konklusjonen fra NNU omkring høsting er, at skjæring av greiner med frukter på som så treskes etter innfrysing er den mest aktuelle metoden. Dette krever da tilgang til utstyr for rask innfrysing og fryselagring i nærheten av dyrkingsstedet, noe som allerede finnes i områder med en etablert bærproduksjon for industri (f.eks. i Sogn), men rent klimatisk er flere andre områder aktuelle for tindvedproduksjon. Om tindveden skal ha større betydning som flerårig vekst i Norge utover kommersiell produksjon av frukter og evt. blad, er avhengig av i hvor stor grad flerbruksaspektet ved tindvedproduksjonen kan utnyttes.

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Sammendrag

Conversion from agriculture to forestry is considered a measure for mitigation of atmospheric CO2 but the impacts on soil C and N processes remain still unclear. We investigated heterotrophic respiration (RH), specific carbon mineralization (CMIN) and nitrogen mineralization (NMIN) in Norway spruce (Picea abies (Karst.) L.) and oak (Quercus robur L.) chronosequences on former cropland by laboratory incubation. The RH was estimated as the release of C per gram soil and CMIN as the release of C per gram of soil organic matter (SOM). Seven Norway spruce stands (16–44 years), eight oak stands (4–43 years), a cropland, a 35 years old permanent pasture and a 200-year-old oak-dominated forest were sampled (0–5 cm and 5–15 cm soil layers) in early spring. The SOM content gradually increased with stand age in 0–5 cm but remained the same in the 5–15 cm soil layer. The RH in the 0–5 cm layer gradually increased with time since afforestation in both tree species while there was no change in CMIN. In 5–15 cm, neither RH nor CMIN changed significantly after afforestation, but oak stands had significantly higher RH than Norway spruce. The NMIN and nitrification in 0–5 cm significantly increased with stand age and only nitrification was higher in oak. In 5–15 cm, only NMIN in oak increased with stand age, but both NMIN and nitrification were significantly higher in oak than spruce. Cropland RH, CMIN and NMIN rates were comparable to those found within the first decades of afforestation, whereas the 200-year-old forest and the pasture generally had RH and NMIN rates similar to the older chronosequence stands. We conclude that potential RH and soil N mineralization increased with time since afforestation and were tree species specific. Soil organic C stock gains observed in this area during the first 45 years after afforestation were not driven by decreased SOM decomposability, leaving increased litter C inputs as a more likely explanation. The lower CMIN in the 200-year-old forest suggests that future studies should include older forests to assess if the stability of C and the retention of N may increase in a longer term perspective.

Sammendrag

I denne rapporten er det gitt en vurdering av samfunnsøkonomiske konsekvenser og effekter på klimagassutslipp som følge av innskrenkninger i adgangen til nydyrking av myr. Restriksjoner mot nydyrking av myr vil i liten grad begrense mulighetene for matproduksjon i Norge, men kan føre til reduserte muligheter for nydyrking i områder med små arealer med alternativ dyrkbar jord. Et generelt forbud mot nydyrking av myr antas å føre til en reduksjon i klimagassutslipp mellom 200 000 og 600 000 tonn CO2-ekvivalenter i 2050, avhengig av hvor store arealer myr som ville blitt nydyrket uten et forbud. Et forbud som bare omfatter djup myr antas å føre til en utslippsreduksjon på mellom 150 000 og 450 000 tonn CO2-ekvivalenter i 2050. Nydyrking av myr ved omgraving forventes å gi lavere utslipp enn tradisjonell dyrking, men effektene på kort og lang sikt er foreløpig svært usikre.