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 UH research portal

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 was also awarded with two awards for the best doctoral thesis of 2022 (by Suomen Luonnoinvarain tutkimussäätiö and by the Faculty of Agriculture and Forestry).
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.
Visiting Post-Doctoral researcher Mina Kiani

Mina is a visiting post-doctoral researcher 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. She defended her doctoral thesis in 2023 on the topic Closing the phosphorus cycle by recycling lake sediments in agriculture and it was accepted with the highest grade, passed with distinction.
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, but also on other ways to recycle phosphorus.

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. 
Doctoral student Samuel Amoah
Samuel is an agricultural scientist with special interests in indoor agriculture, hydroponics and sustainable plant production systems. In his doctoral studies he is currently researching on finding the best practices for using nutrient enriched biochars in boreal conditions.

Doctoral student Jonna Pärssinen

 Jonna is a doctoral student working on sustainable ways to grow cranberries, including exploring the potential of biochars in berry production.

Visiting doctoral student Sharifa Nabavi
 A PhD Student in Crop Physiology, University of Sari Agricultural Sciences and Natural Resources and visiting researcher in University of Helsinki. Her research directions are to identify practical and low-cost absorbents such as biochar for removal and immobilization of heavy metals in wastewater and soil, in addition, the possibility of simultaneous use of biochar and phytoremediation to reduce the negative effects of heavy metals and their damages after entering in the food chain.

MSc student Heikki Sikanen 

MSc student Joni Vihavainen 
MSc student Zannatul Ferdous

MSc student Tatu Puttonen


AgriChar group in summer 2023

Group meeting in autumn 2023

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. 
Completed MSc. theses: 
  1.   Anu Suwal (Effect of lake sediments from range of eutrophic lakes on ryegrass growth and nutrient uptake)
  2.  Tuuli Markkanen (Development of sustainable practices for using lake sediment as growing medium for grass production)
  3.  Suvi Tikka (Effect of biochar on soil aggregate stability, water retention capacity and chemical properties in field nine years after biochar application). 
  4. Topi Kopakkala (Biochar as a planting soil component for urban trees: a short-term study from Hyväntoivonpuisto, Helsinki).
  5. Annukka Kukkola (The effects of biochar and fertilisation strategies on soil fertility and cereal growth on nutrient deficient soil eight years after biochar application)
  6. Eiko Höglund (The effects of biochar on soil biota in temperate and boreal agricultural soils).
  7.  Vilja Jyrinki (Impact of biochars on microbial biomass carbon and soil respiration in forest soils)
  8. 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)
  9.  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)
  10. 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)
  11. Samuel Amoah (The effects of biochar on the soil properties and on yield formation of pea (Pisum sativum L) nine years after application) 
  12.  Katariina Hämäläinen (The effects of biochar on soil moisture and nutrient concentrations and yield components of oat (Avena sativa L.) five years after application.)
  13.  Heidi Hovi (Biochar effects in soil properties and on the yield and species composition of grass).
  14.  Jure Zrim (Medium-term effects of biochars on earthworms in two contrasting soils in Southern Finland)
  15. Stefano Caro (Aalto University, Thermochemical Valorization of Waste: Pyrolytic Conversion of Horse Manure)
  16. Pierre Boivin (Plant uptake of biochar nutrients)
  17. Alma Lehti (Effects of biochar on the yield and species composition of grass)
  18. Juho Honkala (Effects of biochar on faba bean yield formation)
  19. Tuure Parviainen (Effects of biochar on earthworms).
  20. Heedo Lee (Availability of biochar-K to plants)
  21. Tero Brandstaka (Effects of biochar on N dynamics)
  22. Chen Xiaoyulong (Effects of biochar on turnip rape yield formation) 
  23. Jarkko Hovi (Effects of biochar on soil particle stability and P-retention)
  24. Chiara Pituello (Plant uptake of biochar nutrients) 
  25. Johanna Muurinen (Assessment of biochar verification methodology)
Former visitors

Visiting senior researcher Dr. Dilfuza Egamberdieva visited us in 2022. 
Visiting doctoral student Mohammad Ghorbani, visited us in 2023.
Visiting doctoral student Elnaz Amirahmadi, visited us in 2023.


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


Our work has been written about in several newspapers and magazines, including:
  1. Science Magazine 2 May 2023 (story covered also by ScienceDaily, and Mirage) 
  2.  Bioenergialehti 1 March 2023 
  3.  YLE News, 4 October 2021 (story covered also by ScienceDaily,, NewsWise, RitzHerald and Mirage).
  4.  Maatilan Pellervo, December 2019. 
  5.  Karjalainen 4 October 2019
  6.  Tekniikka & Talous 5October 2018
  7. Farmi 4/2018
  8.  Puutarha & kauppa, 9 March 2017
  9.  Ekoelo, February 2015
  10.  Helsingin Sanomat, 22 May 2014
  11.  Energia ja Ympäristö, May 2011   
  12. Yliopistolehti, December 2010  


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)