The production technology of biochars has developed a lot since the beginning of our biochar journey in 2010 (for example, nowadays the dry bulk density of biochars tends to be in the range of only 100 kg per m3!) and we were wondering, whether there is any added value of activating and nutrient-enriching already-high-quality biochars before field application or not. We were also wondering, how can we practically arrange such activation process for large amounts needed for field experiments?
In spring 2023, as part of the doctoral research of Samuel Amoah, we did the large-scale biochar activation and applied the differently activated biochars to our long-term field experiments in Helsinki. The days were long (and ended often in moonshine) but thanks to the great teamwork we were able to successfully complete the two-phase activation process (acid treatment+nitrogen enrichment) on time, apply the biochars to the fields and start the measurement campaigns of greenhouse gas emissions, soil moisture and barley growth. This project is supported by Tiina and Antti Herlin Foundation, Olvi foundation and AGFOREE doctoral school of University of Helsinki.
The measurement season naturally included also soil and plant sampling, and also some first tests on the quality of the biochars used. We were happy to have two visiting doctoral researchers, Mohammad Ghorbani and Elnaz Amirahmadi, to join us for May and June, in addition to our fresh MSc students Zannatul Ferdous and Tatu Puttonen.
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| In spring 2023, University of Helsinki AgriChar research group activated biochars in large scale and studied the effects of these biochars on soils and plants |
The month of June was extremely dry and hot for the growing season 2023 in Southern Finland and Estonia, where our field experiments are running. This meant that the emergence, tillering and growth of barley was not even and at times, growth even stunted. Such hot and dry conditions, however, are suitable for experimental purposes to see if the activation treatments were able to improve the effects of already highest-grade spruce biochars on soil water retention.
We were stunned to see very clear benefits of biochar activation on first biomass yields, actually even doubling the biomass yield compared to control- whereas in water-only activated biochars there were no improvements of barley biomass yield and the fertilizer effects were clear. It seems that the added nitrogen in such nutrient enrichment practices can have a strong effect, even to the extent that the added granular fertilizer effect was left redundant and activated biochar alone was enough for sustaining higher yields. We are looking forward for longer-term effects of such activated biochars, please stay tuned for updates.
