What does Bulgarian research show?
A field experiment with maize on an alluvial meadow soil was conducted at Tsalapitsa in 2019–2021. Milena Mitova, Martin Nenov and Svetla Rousseva of the Nikola Poushkarov Institute studied the combined application of oak-bark biochar and nitrogen fertilisation. A poster abstract published in 2023 reports a statistically significant reduction in bulk density and an increase in total porosity.
This is a specific finding for a particular soil and combination of treatments. The published abstract is not enough to set an application rate for another farm or promise a yield increase.
Another research area concerns soils affected by industrial contamination. In a notice dated 3 February 2026, the Agricultural Academy describes a Nikola Poushkarov Institute project involving laboratory and pot experiments with soils from the areas of Aurubis-Pirdop, Asarel-Medet and Kremikovtsi. The work examines how biochar affects the mobility and availability of contaminants to plants.
Reducing the mobility of a metal does not mean removing it from the soil. This application requires a specialist risk assessment. The institutional notice describes the project and methods; it does not replace a full report of results or permission for a specific use.
Sources: The Tsalapitsa field experiment · Research on biochar in industrially affected soils
Where are the practical opportunities for agriculture?
For a farm, the useful starting point is the problem to be addressed. The goal may concern water management, nutrients or particular physical and chemical soil properties. Soil analysis, material assessment and a choice of observations follow, so that any change can be evaluated.
Results from pots and horticultural growing media also have value, but conditions differ from the field. In the study by Blok and colleagues, biochar properties, including alkalinity and salinity, matter to suitability in mixtures. This shows why selection needs to be specific to the medium and crop.
Sources: Choosing and applying biochar in agriculture · Biochar in horticultural growing media
From residual biomass to an assessed product
For producers, the opportunity starts with knowing the feedstock. Traceable origin, process control and data on the resulting material are needed. The alternative uses of the same residual resource also need to be assessed.
With wood residues, for example, it is necessary to establish whether treated wood or contaminants are present. After production, analysis, representative sampling and a link to the batch provide a basis for assessing suitability. A standard such as EBC can guide quality assessment within its defined scope; it does not by itself replace applicable legal requirements.
Sources: Biochar production and quality · Biochar and climate change mitigation
How is long-term carbon storage demonstrated?
Some of the carbon taken up by plants can remain in biochar for a long time. A climate assessment also needs to consider emissions along the chain, persistence, end use and a justified scenario without the project.
A tonne of biochar produced is not the same as a tonne of CO₂ removed. A product certificate is not automatically a carbon credit either. A climate claim needs traceable data and verification under the relevant methodology.
Sources: Biochar and climate change mitigation · Tracking carbon storage
How can a practical trial begin?
A useful starting point is a limited trial with a goal defined in advance. After assessing the suitability of the material and soil, prepare a plan that includes:
- A description of the soil, crop and problem to be investigated.
- An identified material and an analysis linked to the batch being used.
- Comparable plots with and without biochar, with replication according to the resources available and the agronomic plan.
- The same management of the comparison plots, apart from the amendment being tested.
- Selected indicators, observation periods and records of rainfall, irrigation, fertilisation and field operations.
Positive, neutral or undesirable: every result is useful when reliably documented. It can help decide whether to extend an application, change the approach or reject a particular material.
What is the association’s role?
Our aim is to connect farmers, researchers, producers and other specialists around practical questions that can be tested. We want accessible knowledge to support better decisions, and experience to be documented so that others can evaluate it.
This involves two equally important areas: soil health and long-term carbon storage. Each needs its own evidence; the most useful solutions seek compatibility between them.
Do you have research, practical experience or an idea for collaboration? Tell us at alex@biocharbulgaria.org.