AgriChar research group

What we do

Throughout the past two hundred years, the mankind has been emitting increasing amounts of greenhouse gases to the atmosphere and by doing so, likely contributing to the climate change. CO2 is considered to be the most important of the greenhouse gases and new ways to sequester it from the atmosphere are actively looked for. One of the most promising options worldwide for managing the CO2 is to develop sustainable biochar systems. Mixing biomass that has gone through a pyrolysis process, to soil might lead us even to a carbon-negative agriculture. Such a practice is especially promising if taken into account that biochars hold carbon in the soil for hundreds and even thousands of years.

In addition to that, auxiliary effects from adding some biochars to soil might further reduce greenhouse gas emissions as well as bring along desired effects to the environment. These effects include reductions in the fertilizer need by increased nutrient uptake efficiencies, improved soil physical structure as well as decreased nutrient leaching from the fields.

On the other hand, as the biochars once applied to the soils cannot practically be removed from the soil, the question: are they safe? needs to be answered before the practice could be widely adopted. Some of the most crucial gaps in the current scientific understanding of the functioning of biochars in soil and environment and its role for plants are due to the lack of data on:

   i. the long-term (i.e. more than 5 years) effects under field conditions on soil and plant properties;
   ii. studies under boreal conditions;
   iii. the biochar effects on soil biota under field conditions
   iv. changes occurring on the biochar surfaces.

Our research group targets these gaps focusing mainly on the effects of biochar systems on the physico-chemical properties of soil, on soil biota and on the yield formation and nutrition of field crops.

We have also ongoing projects in the areas of, among others, using biochar for re-using the phosphorus in lake sediments and research on recycling industrial fertilizers (e.g. biogas digestate, composts, meat bone meal).

Group members 

The group is led by adjunct professor in agroecology, university lecturer in crop science Dr. Priit Tammeorg
ResearcherID I Google Scholar I ResearchGate I TUHAT

Priit is interested in solutions increasing the sustainability of
agriculture: nutrient recycling, soil fertility, organic farming and biochar. The main focus of his doctoral thesis was to study the effects of biochar use as a soil amendment on soil fertility, earthworms and plant properties in boreal soils. His current work as a PI of the AgriChar group continues along these lines and is focused on exploring the mechanisms of the short and long-term effects of biochar in boreal soils as well as novel ways to recycle nutrients in the agriculture.


Visiting Post-Doctoral researcher  Subin Kalu

Subin is a post-doctoral researcher interested in exploring environment friendly solutions. For his doctoral studies, he focused on the long-term effects of biochar for sustainable agriculture in boreal soils. His studies emphasized on the effects of biochar on soil physico-chemical properties, greenhouse gas emissions, as well as plant nutrient uptake in long-term, his doctoral thesis was accepted with distinction in autumn 2022 from University of Helsinki. He continues his work as post-doctoral researcher focusing on biochar-nutrient-soil interactions and is working mostly in
North Carolina State University but also as a visiting researcher in AgriChar group.
Doctoral student Mina Kiani

Mina is a D.Sc student in Agroecology at University of Helsinki and joined the AgriChar group in 2017. She is interested in finding solutions for closing the nutrient leakage from the cycle via reusing lake sediments in agriculture and landscape engineering. Her current research focuses on comparing different ways of sediments applications to soil to examine nutrient retention in topsoil and to quantify their effects on environment and crops.

Doctoral student  Jure Zrim

Jure is a D.Sc. student in Agroecology at University of Helsinki, who joined the AgriChar group already for his MSc thesis work in 2015. He is investigating the effects of biochars and recycled organic fertilizers on soil biota in Finnish boreal conditions. His study focuses on medium– and long–term effects of softwood biochars on earthworm and microbial compositions, physicochemical properties of soil and plant growth.

 Doctoral student Mari Unnbom
 Mari is a doctoral student in Agroecology at University of Helsinki since May 2022. Mari was a project coordinator in HYKERRYS-projects (2017–2021) where recycled fertilizers were studied in a five-year field experiment in Haltiala, Helsinki. Now she is using the data gathered from HYKERRYS field experiment to study the effects of recycled fertilizers and soil amendments to soil properties, yield formation and plant nutrient uptake. 

Visiting senior researcher Dr. Dilfuza Egamberdieva, Research associate at the Leibniz Centre for Agricultural Landscape Research (ZALF), Germany, and Head of the Research Lab at the   National University of Uzbekistan. Dilfuza is a renowned environmental microbiologist and soil scientist. The main focus of her research is directed toward an understanding of the structural and functional organization of plant and soil microbial communities under various environmental ecosystems and their role in soil fertility and crop productivity. Since 2015 she is involved in biochar research, particularly as a beneficial soil amendment, and its impact on crop productivity. Dilfuza contributes to our work regarding recycling fertilizers from oil shale ash and we work on a joint publication since her visit in 2022.

MSc. student Tuuli Markkanen

MSc student Heikki Sikanen 

 MSc student Anu Suwal

MSc student Joni Vihavainen

Group meeting in 2021

AgriChar group in summer 2022

We work in co-operation with several other researchers from the University of Helsinki:

Dr. Asko Simojoki
Dr. Petri Penttinen
Dr. Kristiina Karhu
Prof. emer. Juha Helenius
Dr. Michael Starr  

Adj. Prof. Frederick Stoddard
Prof. Pirjo Mäkelä
Dr. Olga Tammeorg
Doctoral student Mr. Jukka Kivelä

Former group members

Biar Deng

In spring 2020, Biar finished his D.Sc. on soil fertility and crop yield improvement through inclusion of multipurpose trees (Acacia seyal.L) and biochar application in drylands agrosystems; case study South Sudan. 
MSc. theses successfully accomplished: 
  1.  Suvi Tikka (Effect of biochar on soil aggregate stability, water retention capacity and chemical properties in field nine years after biochar application).
  2. Topi Kopakkala (Biochar as a planting soil component for urban trees: a short-term study from Hyväntoivonpuisto, Helsinki).
  3. Annukka Kukkola (The effects of biochar and fertilisation strategies on soil fertility and cereal growth on nutrient deficient soil eight years after biochar application)
  4. Eiko Höglund (The effects of biochar on soil biota in temperate and boreal agricultural soils).
  5.  Vilja Jyrinki (Impact of biochars on microbial biomass carbon and soil respiration in forest soils)
  6. Antti Ali-Lekkala (The effect of pinewood biochar on the properties and hydrology of clay loam soil and the growth and development of Pea (Pisum sativum L.) in the temperate climate of southern Finland)
  7.  Niina Välinen (The physicochemical effects of softwood biochar on soil properties and yield formation of pea (Pisum sativum L.) eight years after application in Southern Finland)
  8. Aino Härkönen (The effects of spruce biochar on soil fertility and barley (Hordeum vulgare L.) yield formation eight years after application to nutrient deficient soil)
  9. Samuel Amoah (The effects of biochar on the soil properties and on yield formation of pea (Pisum sativum L) nine years after application) 
  10.  Katariina Hämäläinen (The effects of biochar on soil moisture and nutrient concentrations and yield
    components of oat (Avena sativa L.) five years after application.)
  11.  Heidi Hovi (Biochar effects in soil properties and on the yield and species composition of grass).
  12.  Jure Zrim (Medium-term effects of biochars on earthworms in two contrasting soils in Southern Finland)
  13. Stefano Caro (Aalto University, Thermochemical Valorization of Waste: Pyrolytic Conversion of Horse Manure)
  14. Pierre Boivin (Plant uptake of biochar nutrients)
  15. Alma Lehti (Effects of biochar on the yield and species composition of grass)
  16. Juho Honkala (Effects of biochar on faba bean yield formation)
  17. Tuure Parviainen (Effects of biochar on earthworms).
  18. Heedo Lee (Availability of biochar-K to plants)
  19. Tero Brandstaka (Effects of biochar on N dynamics)
  20. Chen Xiaoyulong (Effects of biochar on turnip rape yield formation) 
  21. Jarkko Hovi (Effects of biochar on soil particle stability and P-retention)
  22. Chiara Pituello (Plant uptake of biochar nutrients) 
  23. Johanna Muurinen (Assessment of biochar verification methodology)


University of Helsinki biochar research group works in co-operation with other institutions :


Our work has been written about in several Finnish national newspapers and magazines, including:
  1. Yliopistolehti, December 2010  
  2.  Energia ja Ympäristö, May 2011    
  3. Helsingin Sanomat, 22 May 2014
  4. Ekoelo, February 2015
  5. Puutarha & kauppa, 9 March 2017
  6. Farmi 4/2018
  7. Tekniikka & Talous 5October 2018
  8. Karjalainen 4 October 2019
  9. Maatilan Pellervo, December 2019. 
  10.  YLE News, 4 October 2021 (story covered also by ScienceDaily,, NewsWise, RitzHerald and Mirage).


We are very grateful for the financial support that makes our work possible.

Our special thanks go to:
Ministry of Agriculture and Forestry of Finland

Centre for Economic Development, Transport and the Environment
University of Helsinki  

Jenny and Antti Wihuri Foundation
Ministry of the Environment  
Finnish Cultural Foundation
Tiina and Antti Herlin Foundation
Maj and Tor Nessling Foundation
Niemi Foundation
Olvi Foundation
Emil Aaltonen Foundation
August Johannes and Aino Tiura Agricultural Research Foundation

Estonian Agricultural Registers and Information Board
EIT Climate-KIC 
Maiju ja Yrjö Rikalan puutarhasäätiö 


Please contact us by e-mail: priit . tammeorg (at)