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Erik Karltun

Erik Karltun
Associate professor in soil chemistry and pedology. Research on land management in forestry and agriculture for sustainable production and climate mitigation both in Sweden and in sub Saharan Africa. Engaged in Sweden’s reporting of emissions and uptake of green-house gases from land-use, land-use change and forestry (LULUCF) to the UNFCCC.


Being trained in agronomy (soil and plant specialisation) I ended up doing a PhD on soil acidification processes, particularly sulfate adsorption, in forest soils.  That led to a long-standing engagement in soil monitoring of forest soils and the utilization of the soil monitoring data for research and for evidence based policy development and implementation. After a post-doc period at the Macaulay Land-Use Research Institute in Scotland between 1998 and 1999 I returned to SLU to work with research and teaching. The research focused on recycling of nutrients in the forestry sector and carbon sequestration in forest soils.  From the year 2000 and onwards I have also been involved in research on soil fertility management in sub Saharan Africa, particularly in Ethiopia. In this context I expanded the scope of my research to include analysis of driving factors behind land-use changes and possible ways of counteracting negative impacts. In these studies we work with participatory approaches together with researchers of different specialisation. This work now includes research on the use of biochar in agriculture to sequester carbon and improve soil fertility.


I have been teaching at SLU for more than 30 years. At present, I am course responsible for the MSc course Soils of the World and Sustainable Soil and Water Management (MV0215). Over the years I have been teaching soil science, biogeochemistry, environmental science and tropical agriculture. For many years I also led the training of the field staff of the Swedish Forest Soil Inventory.

Apart from teaching at BSc and MSc level I have been engaged in graduate training (PhD level). As study director at the Department of Forest Soils I, together with colleagues at the Department of Soil Science, took the initiative to start the SLU graduate school “Focus on Soils” in 2002 and acted as one of two co-ordinators between 2002 and 2008. It was the first graduate school of its kind at SLU. From 2008 until 2012 I was the study director for graduate studies at the newly formed Department of Soil and Environment.


Presently I lead a small research group focusing on the effect of land-use on soil fertility and carbon sequestration. I am the PI of the project “Market driven afforestation – trajectories in social resilience and environmental sustainability under land-use intensification”. We look at how a rapidly expanding cultivation of an Acacia species for the production of charcoal has influenced the local economy and the livelihoods of the community. Getachew Tiruneh, PhD student, looks specifically on the effects on carbon sequestration on a landscape scale and the sustainability of the cultivation with respect to nutrient cycling.

I am also the PI and coordinator of international research project “BICEPS - Biochar Integration in Small-Holder Cropping Systems –Economy Food Product Value Chains, Climate Change Resilience and Soil Fertility” with partners from Norway, South Africa and Kenya.  Daniel Basalirwa is a post-doc researcher in the project and we are interested in getting a deeper insight in how the presence of biochar influence nitrogen cycling in agricultural soils.

In the project “Biochar Stability: supporting transparent & reliable carbon removal In that project the post-doc researcher” led by Cecilia Sundberg I work together with the post-doc researcher Haichao Li  on improving the methodology we use to determine the stability of biochar in soils. 

Environmental analysis

Since 2005 I am part of the team at SLU that compiles the annual Swedish reporting on emissions and uptake of green-house gases from land-use, land-use change and forestry (LULUCF) which is submitted to the UN Framework Convention on Climate Change (UNFCCC) by the Swedish government. My responsibility is the calculations of emissions and uptake of carbon dioxide in litter and soil carbon pools in forest- and grassland soils.  This work is carried out in an international context and I participate on behalf of UNFCCC as an expert reviewer of the submissions of other countries.

From 1993 until 1998 I was the project manager for the Swedish Forest Soil Inventory (SFSI). 

Between 2012 and 2014 I was hired as a full-time international consultant by the Ethiopian Agriculture Transformation Agency to work with the Ethiopian Soil Information System (EthioSIS). I was responsible for inventory design, quality control/quality assurance and data evaluation. The work resulted in soil fertility atlases for all major regions in Ethiopia and revised fertilizer recommendations based on soil inventory data. 


In my work I collaborate with partners in different universities, government authorities, international research institutes, NGOs and private companies. Active collaborations include Ethiopia Forest Development, CIFOR, Eco Innovation Foundation, University of Gondar, University of Nairobi, Wondo Genet College of Forestry and Natural Resources, University of KwaZulu Natal, Norwegian University of Life Sciences, Norwegian Geotechnical Institute, Swedish Forest Agency, Swedish Environmental Protection Agency and VA Syd.


I have supervised three PhD students (see links below) as main supervisor and five as co-supervisor.  

Caroline Rothpfeffer, 2007: From wood to waste and waste to wood – aspects on recycling waste products from the paper-pulp mill to the forest soil 

Carina Ortiz, 2012: Sink or source? : uncertainties in large scale model predictions of forest soil organic carbon dynamics.

Workneh Bedada, 2015: Compost and fertilizer - alternatives or complementary? : management feasibility and long-term effects on soil fertility in an Ethiopian village

I have also supervised > 20 MSc theses at both Swedish and Ethiopian MSc programs.

Selected publications

2020-2024 (or more publications):

Azzi, E. S., H. Li, H. Cederlund, E. Karltun, and C. Sundberg. 2024. Modelling biochar long-term carbon storage in soil with harmonized analysis of decomposition data. Geoderma 441:116761.

Karan, S. K., F. Osslund, E. S. Azzi, E. Karltun, and C. Sundberg. 2023. A spatial framework for prioritizing biochar application to arable land: A case study for Sweden. Resources Conservation and Recycling 189.

Kätterer, T., D. Roobroeck, G. Kimutai, E. Karltun, G. Nyberg, C. Sundberg, and K. R. de Nowina. 2022. Maize grain yield responses to realistic biochar application rates on smallholder farms in Kenya. Agronomy for Sustainable Development 42.

Azzi, E. S., E. Karltun, and C. Sundberg. 2022. Life cycle assessment of urban uses of biochar and case study in Uppsala, Sweden. Biochar 4.

Hounkpatin, K. O. L., J. Stendahl, M. Lundblad, and E. Karltun. 2021. Predicting the spatial distribution of soil organic carbon stock in Swedish forests using a group of covariates and site-specific data. Soil 7:377-398.

Lindahl, B. D., J. Kyaschenko, K. Varenius, K. E. Clemmensen, A. Dahlberg, E. Karltun, and J. Stendahl. 2021. A group of ectomycorrhizal fungi restricts organic matter accumulation in boreal forest. Ecology Letters 24:1341-1351.

Löfgren, S., J. Stendahl, and E. Karltun. 2021. Critical biomass harvesting indicator for whole-tree extraction does not reflect the sensitivity of Swedish forest soils. Ecological Indicators 132.

Karltun, E., J. Stendahl, J. Iwald, and S. Löfgren. 2021. Forest biomass accumulation is an important source of acidity to forest soils: Data from Swedish inventories of forests and soils 1955 to 2010. Ambio.

Azzi, E. S., E. Karltun, and C. Sundberg. 2021. Assessing the diverse environmental effects of biochar systems: An evaluation framework. Journal of Environmental Management 286:112154.

Azzi, E. S., E. Karltun, and C. Sundberg. 2021. Small-scale biochar production on Swedish farms: A model for estimating potential, variability, and environmental performance. Journal of Cleaner Production 280:124873.

Sundberg, C., E. Karltun, J. K. Gitau, T. Kätterer, G. M. Kimutai, Y. Mahmoud, M. Njenga, G. Nyberg, K. Roing de Nowina, D. Roobroeck, and P. Sieber. 2020. Biochar from cook stoves reduces greenhouse gas emissions from smallholder farms in Africa. Mitigation and Adaptation Strategies for Global Change 25:953-967.



Researcher at the Department of Soil and Environment; Biogeochemistry of Forest Soils
Telephone: +4618671277, +46706901277
Postal address:
Box 7014
750 07 Uppsala
Visiting address: Lennart Hjelms väg 9, Uppsala