How do softwood biochars affect the microbial communities and greenhouse gas emissions from agricultural soils in southern Finland? Miten havupuupohjaiset biohiilet vaikuttavatmaanpieneliöyhteisöihin ja kasvihuonekaasupäästöihin biohiilikokeissa Etelä-Suomessa?

Research output: Conference materialsPoster


Biochar (BC) is a carbon rich pyrolysed solid that can be used as a soil amendment material. It is a promising solution to sequester carbon, enhance soil fertility and potentially increase crop yields [1, 2]. While biochar studies have increased exponentially over the last years, only few of them were done in a long-term field experiments. BCs can have significant impacts on soil organic carbon levels and physicochemical conditions, which consequently affect soil micro- and macro-biota. Changes in microbial communities have been reported, but the underlying mechanisms are still poorly understood. It is therefore important to understand how the key biological components in soil such as microbial communities respond to the application of biochar in the long-term. In this study, we aim to uncover biochar-induced long-term changes under field conditions in Finnish soils and soil ecosystems and unveil the mechanisms behind the changes in relation to soil microbiome.

The study was conducted in Southern Finland in a fertile Stagnosol and a nutrient deficient Umbrisol, four and five years after biochar amendment, respectively. Biochars were produced from spruce (Picea abies (L.) H. Karst.) and pine (Pinus sylvestris L.). The results in this poster present the maximum applied BC rates of 10 t ha-1 and 30 t ha-1 in Stagnosol and Umbrisol, respectively. The fields had different fertilizer strategies. The Stagnosol field was fertilized with three levels of mineral fertilizer NPK (30, 65 and 100%), whereas the treatments in the Umbrisol field included fertilization with meat bone meal and mineral fertilizer as well as zero fertilization.

Soil samples for microbial analyses were collected in September 2015 and stored at –80 °C. Soil DNA was extracted from 0.25 g soil with PowerSoil DNA extraction kits (MoBio, Carlsbad, CA, USA). Quality of extracted DNA was checked with electrophoresis and DNA yield was assessed by NanoDrop. The hypervariable V3-V4 region in 16S rRNA gene was amplified using primers 341F and 785R. Purified amplicons were sequenced on Illumina MiSeq platform, producing 2 x 300-bp paired-end reads (Institute of Biotechnology, Helsinki, Finland). Sequence analysis was conducted using USEARCH [3] and Mothur [4]. Phospholipid fatty acids were analyzed from the same soil samples as 16S rRNA. The greenhouse gas (GHG) fluxes from soil (CO2, CH4 and N2O) were measured by a closed dynamic chamber method with a portable FTIR gas analyzer (DX4015; Gasmet Technologies Oy, Helsinki, Finland). GHG fluxes were measured in September 2015 after the harvest. During the measurement, chamber was closed for 2 min, at which time gas samples were taken at 6 sec intervals. Between the samplings the chamber was vented. Chamber was equipped with a 40 x 40 mm axial flow fan (Multicomp, Chicago, USA) and a thermometer (product nr 340, Suomen Lämpömittari Oy, Helsinki, Finland). The data measured during the first minute was intentionally discarded due to possible errors (e.g. gas sample left from previous measurement, pressure disturbance). Chamber temperature was recorded at the beginning of measurement.

We discovered higher abundance of Acidobacteria and Elusimicrobia phyla in BC treatment of Umbrisol. No such effects were observed in Stagnosol, where BC plots were instead more abundant in Proteobacteria. Acidobacteria are sensitive to pH and prefer lower pH soils, yet the BCs used in our studies had negligible liming effect. Previous studies suggest Acidobacteria are either not affected by biochar amendment [5, 6] or decrease in abundance [7] which is in contrast to our results. Greater abundances of Elusimicrobia and Proteobacteria were also detected in BC amended soil by Liu et al. [8] and Zheng et al. [9], respectively. Site differences in bacterial abundance were also detected; Umbrisol had higher abundances of Proteobacteria and Actinobacteria, but lower abundances of Acidobacteria and Bacteroidetes.

There were no significant differences in greenhouse gas emissions (i.e. CO2, CH4 and N2O levels) after the harvest between BC plots and control plots without BC. Phospholipid Fatty Acid Analysis results are currently being analyzed and will be presented in the final presentation.
Original languageEnglish
Publication statusPublished - 9 Jan 2019
MoE publication typeNot Eligible
EventX Maaperätieteiden päivät 2019 - Helsinki, Finland
Duration: 9 Jan 201910 Jan 2019


ConferenceX Maaperätieteiden päivät 2019
Internet address

Fields of Science

  • 4111 Agronomy
  • biochar
  • field experiment
  • microbial ecology

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