2nd European Biochar Summer School - Follow-up

Take home messages and video lectures available

Organised by the EU-COST Action Biochar, eBRN and Ithaka Institut -This 2nd Summer School on Biochar was highly succesful and delivered considerable output such as 'take home messages' from the participants and video lectures by international experts.

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Watch the video lectures here

View photos from the Summer School here

Read about the student participants here


Take Home Messages from the 2nd European Biochar Summer School 2013

Pre-treatment is necessary. Biochar’s abilities in soil will only stand out if it isn’t applied straight out of the pyrolysis. It’s important to understand the characteristics not only of the biochar but also of the soil and crop in question to know how to prepare biochar for application. Or, in Gerald’s (Dunst) words, if it doesn’t work, you’re doing something wrong.

Be creative! To get the most out of biochar, use it for several purposes during its life cycle. There are several benefits of biochar use on farm-scale before soil application. For instance, first add it to manure to reduce odours and adsorb nutrients, and then add the biochar-manure to compost to enhance the composting process, then use the resulting biochar compost in agriculture.

Many things must match to make larger-scale production feasible. Steady income of cheap feedstock (preferably waste that it is paid for handling), strong and committed local customer base with good results of biochar use, ability to use biochar for producer’s own needs, possibility to use the synthesis gas for power and heat production, etc.


The "retort kiln" (adam-retort) has still great potential for further development and we need research on it, try to get Universities, Research Department, etc., interested in this technology.

One argument is that biochar is expensive to produce, efficient retort carbonization might be the key for it to produce biochar with less costs?

Biochar must be "loaded" means pre-treated with dung etc., prior to application in soils


It is clear that biochar can improve soil quality and plant growth. However, more research is needed to define all mechanisms, which are involved. 

Biochar characterization methods are key to understand biochar behaviour. 

The determination of biochar stability is a challenge and a combination of field and incubation long-term experiments may be of help.


Biochar is beneficial in many ways and particularly agronomic benefits are quite well known across a wide section of society. How biochar works exactly is still contentious and still need a lot of scientific work. Biochar is highly variable hence difficult sometimes to draw general conclusions on its effects on e.g soil which in itself is very variable. Standardization of biochar could help address this.


Biochar is a highly heterogeneous material; the absolute need for taking representative samples is a logical conclusion of that

Biochars shouldn’t be evaluated as good/bad, different applications demand different characteristics, thus, properties that make it good for one purpose might make it unsuitable for another one

Biochar is a tool to change soil properties but it is not a wonder product that boosts yields by itself, post-production processing and application with other material is necessary


Selection of appropriate feedstock, pyrolysis temperature, concentrations, and their interaction deserve consideration prior to biochar addition to soil as some biochar have negative impacts to soil/microbe/plants (mostly at higher concentration). Better to use small biochar size particle and biochar effect can be improved when it is applied with other organic amendment and fertilizers. Proper sampling of biochar or/and soil is very important before analysis (help to reduce variation and errors)


The biochar-microorganism-plant-soil-system is far too complex to be explained by simple reductionist mechanisms. The unknowns far outweigh the knowns (conclusion after only one and a half day of participation). Caveat emptor.


Biochar needs to be conditioned/pre-treated prior to application in soil

Before working on composted biochar, first of all I need to understand compost

To understand long-term effects of biochar, we should look at sites where biochar was already used in the 19th and early 20th century!


Biochar works in interactions with microorganisms

Redox/electric behaviour probably are a key in biochar functioning/impacts

Biochar can be a very good way to rapidly lower redox potential in degraded soils and restore fertility


Consider interactions in the environment when looking at BC isolated in the lab.

In terms of soil remediation, use biochar as a tool for refertilisation to get plants started and to create a sustainable environment.

There may be a good response to biochar on field, even if there are extractable pollutants within the biochar.


Biochar has to be activated, before using in soils

Biochar without nitrogen can’t work in soils

Most of the scientific experiments are working still with un-activated biochar - so we will not get the results witch would possible in this area!


Biochar can be applied for many things not only as fertilizer. As Ellen Graber said, germination is faster with little percentages of biochar so biochar not only improves the size and yield of the plant. Like in my research line, as G. Cornelissen's line, biochar can be applied as a great sorbent to sorb different contaminants (organic or heavy metals for example) to decrease the bioavailability of these contaminants. Also Pascal Boivin talked about the decreasing of the run off of some pollutants. Hence, biochar has many other uses than fertilizing.


Due to the different materials which biochar can be produced from and the different production factors as temperature, biochar is very heterogeneous. Maybe a generic method to produce biochar should be applied in order to get fewer heterogeneity. This will help people and investigators to study biochar. Each batch of BC is usually different from the previous one and this make difficult the investigation. There is a need of some guidelines to produce biochar and also to characterise it.

A lot of people are researching with biochar but a network of researchers and research is also needed in order to collaborate and create a council of experts. I saw chemists, biologists and other scientist people in the Biochar Summer School. For example, in my case, I am not used to work with plants however I have some ideas of chemistry of biochar and organic pollutants. Creating this network will help most of us to get a quick help to understand better biochar.


It is necessary to know not only the immediate effect of biochar in soil or growing media but also how it changes the effect of using different biochar,

In order to use the biochar for the remediation of polluted soils more experiment not only in the field but also in laboratory are necessary,

It's necessary to make more research about how biochar can improve crop production in the field and in the greenhouse.


I learned from Heike Knicker how useful it can be to study biochar and soil amended with biochar with solid state NMR.

From Samuel Abiven, I learned that density fractionation would be a good method to study aggregation and association between biochar and soil particles.

It was also useful to learn from Thomas Bucheli how important the sampling method is.


Be critical when choosing methods to analyse your biochar samples! Methods for soil analyses might not be suitable.  

How biochar functions - still many unknowns. Study your biochar properties detailed before using/advicing.

Practice and research go hand in hand. Practice already has belief: If your biochar doesn´t work, you are the one who does something wrong (Gerald Dunst)!


Considerations of Eh (redox potential) and pH (proton concentration) in soil are important to understand fertility and resilience of a agricultural field. The impact of biochar application can also be viewed as a possible amendment towards optimal Eh and pH conditions.

Stability of biochar in soil is very difficult to determine. There are different methods available but they have all their downsides. Carbon sequestration is no more a major reason to use biochar anyway.

Most of our scientific research questions are not relevant for practitioners implementing soil improvement solutions with biochar. Risk assessments (i.e. PAH) have not shown serious problems for the environment. Compared to commercially used agro chemicals, biochar will not seriously harm natural ecosystems. 


Biochar is an interesting, complex, wide and inspiring field of research.

Biochar has peculiar characteristics different from all the other materials we are used to work with.

People working with biochar are amazing!


Analytical methods designed for soils or other solid matrixes must be carefully reconsidered when applied to biochar.

Biochar's labile organic compounds and mineral phases may be the most important actors explaining biochar's reactivity in soils.

Differences of redox potentials could explain a large part of the experimental observations in soil-biochar systems - if only we were able to properly measure it!


There is hope for biochar in a agronomy setting in the western world.

Biochar even has an effect on pests targeting plant leaves

Take home message of Thomas (Bucheli), biochar needs to have multiple benefits


Avoid grab samples

Adapt and validate your (analytical) methods for biochar

Avoid re-condensation of syngas for low pollutant biochars


The use of biochar in green remediation strategies shows clear potential and research in this area was well represented among the student delegates but the role of biochar compost and concrete data from long term field trials is essential to bring the state of the science further and justify field scale application

The use of biochar in conventional agriculture may have limited success. However, as part of a holistic approach to land management and complementary to composting techniques, more positive results may be observed with the use of biochar. Again, long term monitoring is required to confirm this

There is much overlap in biochar research, particularly on the question of stability and structure of biochar but also in terms of nitrogen dynamics. A more cohesive European scale approach is required to avoid repetition of research hypotheses and ensure research is complementary and collaborative rather than repetitive.