Winter meetings before holidays in 2023

Winter arrived early this year in Finland, painting our landscape with a picturesque layer of snow and plunging temperatures. Over the past months, our dedicated team has been immersed in laboratory research, delving into the impact of variously activated biochars on barley yield formation, earthworms, greenhouse gas emissions, and, most recently, nutrient uptake of crops. 

Amid active data collection, we're diligently engaged in the ongoing tasks of data analysis and reporting, covering a broad spectrum of topics in sustainable agriculture. From recycling industrial sidestreams as fertilizers (with a keen eye on their long-term effects on soil fungal communities) to crafting best practices for cultivating cranberries sustainably, our pursuits are diverse and impactful.

 

The Winter Meetings of the AgriChar research group in December provided a valuable opportunity to reconnect and discuss the progress of our various projects. A heartfelt thank you to all AgriChar members and partners for making 2023 an amazing year. As we pause for the winter holidays, let's recharge our spirits and gear up to enter 2024 with steadfast enthusiasm! Special thanks to Camille Michel from UniLaSalle who returned back to France today!

Viikki biochar experiments harvested and sampled for 2023, including earthworms!

Today we have finally completed the sampling campaign for growing season 2023 in our long-term agricultural biochar experiments in Viikki, Helsinki. The growing season was challenging once again with extreme droughts in May and June, and quite some rains in August-September, but once we got the yields collected, we were happy and concluded that the harvesting was, as usual, lots of fun. We are very lucky to have Camille Michel from UniLaSalle, France as a visiting student to help with all the sampling campaigns and later in autumn, with lab work!

After the harvest, we took soil samples of different kinds to see the effects of differently activated biochars on soil carbon, bacteria and fungi, available nutrients but also on water retention curve, greenhouse gas emissions and mineral nitrogen content. All this is part of Samuel Amoah's doctoral thesis.

For the first time since 2015, we also looked into the effects of biochar and fertilizer treatments on earthworms. This is part of the research of our group member Zannatul Ferdous and we were glad this time we had the chance to perform the sampling during rainy days with class: Department of Agricultural Sciences supported us with a brand-new tent for field sampling! Earthworm sampling was completed much quicker than anticipated thanks to motivated team by Zannatul, Camille and also our newest group member, visiting researcher Sharifa Nabavi from Iran. But for the first sampling day, many more AgriChar members gathered to the field for enjoying the good company and learning tips and tricks about earthworm research from Jure. Thanks to all for the nice moments on fields and let's now focus on the lab work. Looking forward for the results!

Added value of activating already-premium-grade biochars? First results from dry spring 2023 promising!

 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.

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.

The ground-breaking doctoral thesis of Mina Kiani received the highest grade, distinction!

Recently the Faculty Council of the Faculty of Agriculture and Forestry, University of Helsinki, decided to afford the pioneering doctoral thesis of Mina Kiani the highest grade, pass with distinction. We are very happy for such a high recognition to our work!

Mina's doctoral thesis "Closing the phosphorus cycle by recycling lake sediments in agriculture" data collection work started in 2017 under the supervision of Dr. Priit Tammeorg, Dr. Olga Tammeorg, Dr. Asko Simojoki and Dr. Petri Penttinen.  The work came to the grande finale on 21 April 2023 with the public defense where Professor Giancarlo Renella, University of Padua, served as the opponent. We enjoyed very much the discussions, both before, during and after the defense, with Prof. Renella sharing his insights to (history of) soil science but also with his latest experiences with biochars and sediments in Italy.

In this work, Dr. Mina Kiani found a sustainable solution for closing the leaking agricultural #phosphorus (P) cycle by #recycling P-rich lake #sediments back to the agriculture. It is globally the first study covering the effects of lake sediment recycling both to lake and to the plants on the shore of the lake over four-year field experiment. What is more, first time ever also the environmental aspects of recycling lake sediments to agriculture were reported over several years. 

 

Mina Kiani's doctoral theis was graded with Pass with distinction

 

We learned that the sediment-based growing media sustained grass biomass yield in the field condition, even though yield enhancement in field experiment was less obvious compared with our previous lysimeter experiment. Sediment from Lake Mustijärv was rich in organic matter and was a good source of several essential nutrients, including P, in plant-available form. In addition to P, the sediment had high solubility of essential plant nutrients including sulfur (S), calcium (Ca), magnesium (Mg), boron (B), zinc (Zn), and a fair supply of copper (Cu). Also, the sediment continuously provided a moderate supply of N to the plants over the four-year field experiment, which was likely due to mineralization of the organic reserves of the sediment.

Considering the environmental impacts, the sediment-based growing media had higher carbon dioxide (CO2) emissions yet broadly similar nitrous oxide (N2O) emissions compared with the soil surrounding the lake. Also, applying a thick layer of excavated sediment (~2000 t ha⁻¹) increased the risk of P and mineral N leaching. The application of biochar increased the amount of N taken up by the plants but did not significantly reduce emissions or leaching.

In addition, sediment-based growing media had different bacterial and fungal community compositions compared with soil. This could result in different mineralization pathways in soil and sediment-based treatments. The bacterial phyla associated with solubilizing P, including Proteobacteria and Chloroflexi, were more abundant in the sediment material than in Soil. This is while the relative abundances of Actinobacteria and Planctomycetes, with the potential to accumulate bioavailable P fractions, were higher in Soil. 

We wish Mina all the best for her career in science and beyond, currently she works for the Natural Resources Institute Finland and continues the ongoing work in AgriChar group as a visiting post-doctoral researcher.

Two fresh publications: Finnish Biochar Guide and new review on biochar as a carrier for beneficial microbes

 We are happy to share that the first ever Finnish  Biochar Guidebook has been published, it is free to download from VYL website! Great teamwork Anu Riikonen Annakaisa Elo Marleena Hagner,  Aino Kainulainen, Kirsi Kuoppamäki, Pirjo Laulumaa, Aki Männistö, Aino-Kaisa Nuotio, Esko Salo, Kari Tiilikkala!

Ensimmäinen Suomen #Biohiili opas julkaistu: Viher- ja ympäristösuunnitteluun, -rakentamiseen ja kunnossapitoon suunnattu biohiiliopas kokoaa yhteen ajankohtaista ja käytännönläheistä tietoa biohiilestä, sen tuotannosta, hyödyistä, ominaisuuksista ja toiminnasta osana maaperää viheralan näkökulmasta. Lataa omaasi: VYL sivut.

 

 

Did you know that #biochar makes a promising carrier for beneficial #microbes? The use of biochar as a carrier of microbial inoculum has been shown to enhance the persistence, survival and colonization of inoculated microbes in soil and plant roots, which play a crucial role in soil biochemical processes, nutrient and carbon cycling, and #soil contamination remediation. Moreover, biochar-based microbial inoculants including probiotics effectively promote plant growth and remediate soil contaminated with organic pollutants. 

Our fresh review study on this is out now, open access! Check it out: The potential of biochar as a microbial carrier for agricultural and environmental applications

Welcome to public defense of Mina Kiani, lake sediments are promising fertilizers!

Mina Kiani, M.Sc. will defend the doctoral dissertation entitled "Closing the phosphorus cycle by recycling lake sediments in agriculture" in the Faculty of Agriculture and Forestry, University of Helsinki, on 21 April 2023 at 12:00. The public examination will take place at the following address: Walter Hall, EE-Building, Agnes Sjöberginkatu 2, Helsinki. Full professor Giancarlo Renella, University of Padua, will serve as the opponent, and Priit Tammeorg as the custos. The dissertation is also available in electronic form in Helda.

 

Mina and colleagues enjoying the data collection back in 2017

 

Prof. Renella will also deliver a seminar on Potential and limitations of dredged sediment application in agriculture: projects outcome and perspectives on Thursday 20th April.

Time: 1:15pm to 2pm.

Location: Sali K110 (Is1), C-Building.

Warm welcome!

 

What are the agronomic and environmental impacts of recycling lake sediments to crop production? Our 4-y field study published, Mina's PhD defense soon!

 We are trying to find a sustainable solution for closing the leaking agricultural #phosphorus (P) cycle by #recycling P-rich lake #sediments back to the agriculture. It is globally the first study that covers environmental aspects of recycling lake sediments to agriculture over several years:

 

Excavating all the 7500 m³ of sediment from a 1-ha shallow eutrophic Lake Mustijärv (Viljandi, Estonia) was the starting point of this work. During the lake restoration, 6.4 Mg of P was removed, including at least 2.4 Mg of P that was potentially bioavailable.

During a four-year field experiment on the shore of the restored lake, various application methods were examined to use large quantities of lake sediments for grass production with the following treatments: the agricultural control soil (Soil) surrounding the lake, pure sediment (Sed), #biochar treated sediment (SB), and biochar and soil mixed with sediment (SSB). In addition to the plant growth investigation, we estimated the environmental impacts of different sediment application methods by analyzing greenhouse gas emissions, N and P leaching, aggregate stability, and soil biota.

From this study we learned that the sediment-based growing media sustained grass biomass yield in the field condition, even though yield enhancement was less obvious compared with our previous lysimeter experiment. Sediment from Lake Mustijärv was rich in organic matter and was a good source of several essential nutrients, including P, in plant-available form. In addition to P, the sediment had high solubility of essential plant nutrients including sulfur (S), calcium (Ca), magnesium (Mg), boron (B), zinc (Zn), and a fair supply of copper (Cu). Also, the sediment continuously provided a moderate supply of N to the plants over the four-year field experiment, which was likely due to mineralization of the organic reserves of the sediment.

Considering the environmental impacts, the sediment-based growing media had higher carbon dioxide (CO2) emissions yet broadly similar nitrous oxide (N2O) emissions compared with the soil surrounding the lake. Also, applying a thick layer of excavated sediment (~2000 t ha⁻¹) increased the risk of P and mineral N leaching. The application of biochar increased the amount of N taken up by the plants but did not significantly reduce emissions or leaching.

In addition, sediment-based growing media had different bacterial and fungal community compositions compared with soil. This could result in different mineralization pathways in soil and sediment-based treatments. The bacterial phyla associated with solubilizing P, including Proteobacteria and Chloroflexi, were more abundant in the sediment material than in Soil. This is while the relative abundances of Actinobacteria and Planctomycetes, with the potential to accumulate bioavailable P fractions, were higher in Soil.

Further study is required to determine if the GHG emissions and nutrient leaching from recycled lake sediment can be reduced by using it in lower quantities, similar to organic fertilizers and soil amendment materials. Also, the life-cycle assessment of environmental impacts of sediment recycling of eutrophic lakes for agricultural purposes is suggested for the future research.

This novel study was third chapter of the doctoral thesis of Mina Kiani. Her thesis “Closing the Phosphorus Cycle by Recycling Lake Sediments in Agriculture” is currently being prepared for printing. 

 Those interested on latest research and developments in the field of recycling phosphorus from lake sediments are most welcome to join the public defense of her doctoral thesis this spring. The details are published soon in the website of AgriChar research group (http://biochar-hy.blogspot.com/) but tentatively, the public examination is planned for 21 April 2023. Save the date!

Please check the following recently published articles for more:

 Kiani, M., Zrim, J., Simojoki, A., Tammeorg, O., Penttinen, P., Markkanen, T., & Tammeorg, P. (2023). Recycling eutrophic lake sediments into grass production: A four-year field experiment on agronomical and environmental implications. Science of The Total Environment, 161881.

Kiani, M., Tammeorg, P., Niemistö, J., Simojoki, A. and Tammeorg, O., 2020. Internal phosphorus loading in a small shallow Lake: Response after sediment removal. Science of The Total Environment, p.138279.

Kiani, M., Raave, H., Simojoki, A., Tammeorg, O. and Tammeorg, P., 2021. Recycling lake sediment to agriculture: Effects on plant growth, nutrient availability, and leaching. Science of The Total Environment, p.141984.

This project was supported by AGROREE doctoral school, Maa- ja vesitekniikan tuki ry, Suomen luonnonsuojelunsäätiö Itämerirahasto, Ella ja Georg Ehrnrooth Foundation, Finnish Cultural Foundation, Niemi Foundation, Tiina and Antti Herlin Foundation& great help of colleagues & friends including Martin Voll, Kalle Köömnemägi, Heli Ahola, Merve Kujala,Helena Soinne, Ave Truhanov, Miia Collander, Markku Tykkyläinen, Marjo Kilpinen, Kaj-Roger Hurme, Sanna Peltola, and Subin Kalu.