Effects of softwood biochars on soil biota in medium-term field experiments in Finland

Biochar soil amendment could be used to sequester carbon, enhance soil fertility and potentially increase crop yields. It can have significant impacts on soil organic carbon levels and physicochemical conditions, which consequently affect soil micro- and macro-biota. It is therefore important to understand how key biological components in the soil such as microbial and earthworm communities response to biochar application in the long-term. This 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.), and applied at the rates of 10 and 30 t ha-1, respectively. Earthworms and soil samples for microbial analyses were collected in September 2015. Soil microbial communities were studied by using phospholipid fatty acid profiling and 16S rRNA gene amplicon sequencing. Casts from the sampled earthworms were collected to investigate the consumption of biochar and the potential of earthworm bioturbation to affect biochar distribution. Additionally, greenhouse gas emissions from soil were measured. Biochar and fertilizer treatments or their interaction had no statistically significant effects on the earthworm abundance, community composition or greenhouse gas emissions in either field. Earthworms had ingested biochar as earthworm casts from biochar treated-plots contained significantly more black carbon than those in the control plots, demonstrating that earthworm bioturbation is a potentially important factor in the translocation of applied biochar in the soil profile. Microbial community structure data will be presented in the final presentation.Non peer reviewe

Implementation and initial calibration of carbon-13 soil organic matter decomposition in the Yasso model

Soils account for the largest share of carbon found in terrestrial ecosystems, and their status is of considerable interest for the global carbon cycle budget and atmospheric carbon concentration. The decomposition of soil organic matter depends on environmental conditions and human activities, which raises the question of how permanent are these carbon storages under changing climate. One way to get insight into carbon decomposition processes is to analyse different carbon isotope concentrations in soil organic matter. In this paper we introduce a carbon-13-isotope-specific soil organic matter decomposition add-on into the Yasso soil carbon model and assess its functionality. The new C-13-dedicated decomposition is straightforward to implement and depends linearly on the default Yasso model parameters and the relative carbon isotope (C-13/C-12) concentration. The model modifications are based on the assumption that the heavier C-13 atoms are not as reactive as C-12. The new formulations were calibrated using fractionated C, C-13 and delta(13) measurements from litterbags containing pine needles and woody material, which were left to decompose in natural environment for 4 years. The introduced model modifications considerably improve the model behaviour in a 100-year-long simulation, where modelled delta(13) is compared against fractionated peat column carbon content. The work presented here is a proof of concept and enables C-13 to be used as a natural tracer to detect changes in the underlying soil organic matter decomposition.Peer reviewe

Effects of a tree row on greenhouse gas fluxes, growing conditions and soil microbial communities on an oat field in Southern Finland

Agricultural ecosystems are facing critical loss of biodiversity, soil nutrients, and cultural values. Intensive crop production has caused landscape homogenisation, with trees and hedges increasingly disappearing from agricultural land. Changes in farming practices are essential to increase biodiversity and improve soil biogeochemical processes, such as nutrient cycling, soil carbon uptake, and sequestration, as well as to improve the resilience and fertility of farming systems. Agroforestry is an important practice for implementing and improving natural and cultural value of landscapes, but in northern countries, agroforestry methods remain rarely utilised. Our study was conducted in Southern Finland on an agricultural field where a row of willow and alder was planted 6 years prior to our study. We concentrated on the effects of the tree row on crop growing conditions and how far from the trees possible impacts can be observed. We studied soil properties, carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) exchange, and soil microbial communities. The impact of trees on crop growing conditions, biomass production, and greenhouse gas fluxes was modest and did not extend further than few meters from the tree row in the warm and dry growing season of 2019. N2O and CH4 fluxes were negligible and the tree row did not increase greenhouse gas emissions from soil. Soil microbial diversity was clearly improved by the presence of trees due to more diverse habitats. The tree row also slightly decreased the estimated annual net emissions of carbon into the atmosphere. Due to positive indications of the effects of agroforestry on biodiversity and carbon uptake, we highly recommend further studies within various agroforestry practices in Nordic countries

Similar temperature sensitivity of soil mineral-associated organic carbon regardless of age

Most of the carbon (C) stored in temperate arable soils is present in organic matter (OM) intimately associated with soil minerals and with slow turnover rates. The sensitivity of mineral-associated OM to changes in temperature is crucial for reliable predictions of the response of soil C turnover to global warming and the associated flux of carbon dioxide (CO2) from the soil to the atmosphere. We studied the temperature sensitivity of C in 63 mu m fractions rich in particulate organic matter (POM). The fractions were isolated by physical separation of two light-textured arable soils where the C4-plant silage maize had replaced C3-crops 25 years ago. Differences in C-13 abundance allowed for calculation of the age of C in the soil-size fractions (old C, C3-C > 25 years; recent C, C4-C <25 years). We incubated bulk soils ( <2 mm) and size fractions sequentially at 6, 18, 26 and 34 degrees C (ramping up and down the temperature scale) and calculated the temperature sensitivity of old and recent C from (CO2)-C-12 and (CO2)-C-13 evolution rates. The temperature sensitivity was similar or slightly higher for POM than for MOM. Within the POM fraction, old C3-C was more sensitive to changes in temperature than recent C4-C. For the MOM fraction, the temperature sensitivity was unrelated to the age of C. Quantitative PCR analysis indicated that the proportions of bacteria, archaea and fungi did not change during incubation. Our results suggest that while OM stabilizing mechanisms affect the temperature sensitivity of soil C, temperature sensitivity appears unrelated to the age of mineral-associated OM.Peer reviewe

Carbon guide : An outlook on carbon in soil and on carbon cultivation

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ARCH 14 - International Conference on Research on Health Care Architecture - November 19-21, 2014, Espoo, Finland - Conference Proceedings

Healthcare Architecture has grown rapidly in recent years. However, there are still many questions remaining. The commission, therefore, is to share the existing research knowledge and latest results and to carry out research projects focusing more specifically on the health care situation in a variety of contexts. The ARCH14 conference was the third conference in the series of ARCH conferences on Research on Health Care Architecture initiated by Chalmers University. It was realized in collaboration with the Nordic Research Network for Healthcare Architecture .It was a joint event between Aalto University, Finnish Institute of Occupational Health (FIOH) and National Institute of Health and Welfare (THL International).The conference gathered together more than 70 researchers and practitioners from across disciplines and countries to discuss the current themes

Implementation and initial calibration of carbon-13 soil organic matter decomposition in the Yasso model

Soils account for the largest share of carbon found in terrestrial ecosystems, and their status is of considerable interest for the global carbon cycle budget and atmospheric carbon concentration. The decomposition of soil organic matter depends on environmental conditions and human activities, which raises the question of how permanent are these carbon storages under changing climate. One way to get insight into carbon decomposition processes is to analyse different carbon isotope concentrations in soil organic matter. In this paper we introduce a carbon-13-isotopespecific soil organic matter decomposition add-on into the Yasso soil carbon model and assess its functionality. The new 13C-dedicated decomposition is straightforward to implement and depends linearly on the default Yasso model parameters and the relative carbon isotope (13C/12C) concentration. The model modifications are based on the assumption that the heavier 13C atoms are not as reactive as 12C. The new formulations were calibrated using fractionated C, 13C and δ 13 measurements from litterbags containing pine needles and woody material, which were left to decompose in natural environment for 4 years. The introduced model modifications considerably improve the model behaviour in a 100-year-long simulation, where modelled δ3 is compared against fractionated peat column carbon content. The work presented here is a proof of concept and enables 13C to be used as a natural tracer to detect changes in the underlying soil organic matter decomposition

Effects of a tree row on greenhouse gas fluxes, growing conditions and soil microbial communities on an oat field in Southern Finland

Abstract Agricultural ecosystems are facing critical loss of biodiversity, soil nutrients, and cultural values. Intensive crop production has caused landscape homogenisation, with trees and hedges increasingly disappearing from agricultural land. Changes in farming practices are essential to increase biodiversity and improve soil biogeochemical processes, such as nutrient cycling, soil carbon uptake, and sequestration, as well as to improve the resilience and fertility of farming systems. Agroforestry is an important practice for implementing and improving natural and cultural value of landscapes, but in northern countries, agroforestry methods remain rarely utilised. Our study was conducted in Southern Finland on an agricultural field where a row of willow and alder was planted 6 years prior to our study. We concentrated on the effects of the tree row on crop growing conditions and how far from the trees possible impacts can be observed. We studied soil properties, carbon dioxide (CO₂), nitrous oxide (N₂O), and methane (CH₄) exchange, and soil microbial communities. The impact of trees on crop growing conditions, biomass production, and greenhouse gas fluxes was modest and did not extend further than few meters from the tree row in the warm and dry growing season of 2019. N₂O and CH₄ fluxes were negligible and the tree row did not increase greenhouse gas emissions from soil. Soil microbial diversity was clearly improved by the presence of trees due to more diverse habitats. The tree row also slightly decreased the estimated annual net emissions of carbon into the atmosphere. Due to positive indications of the effects of agroforestry on biodiversity and carbon uptake, we highly recommend further studies within various agroforestry practices in Nordic countries

Hiiliopas - katsaus maaperän hiileen ja hiiliviljelyn perusteisiin

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