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Dynamics of carbon sequestration and stabilisation in an agricultural long-term trial - DynaCarb

Applicant Steffens Markus
Number 182018
Funding scheme Project funding (Div. I-III)
Research institution Forschungsinstitut für biologischen Landbau (FiBL)
Institution of higher education Research Institute of Organic Agriculture - FiBL
Main discipline Pedology
Start/End 01.01.2019 - 31.12.2022
Approved amount 318'464.00
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Keywords (9)

NanoSIMS; Organic fertilizer; Long-term trial; Soil Organic Matter; Carbon stabilization; Carbon sequestration; Radiocarbon dating; Climate change mitigation; NMR spectroscopy

Lay Summary (German)

Lead
Böden bzw. der darin enthaltene Humus (soil organic matter = SOM) sind die wichtigsten Speicher für Kohlenstoff auf dem Land. Sie enthalten mehr Kohlenstoff als die gesamte Atmosphäre und die weltweite Vegetation zusammen. Intelligente landwirtschaftliche Praktiken werden als Möglichkeit zur Minderung des Klimawandels diskutiert, weil sie die Menge des Humus im Boden erhöhen können und damit aktiv Kohlenstoff aus der Atmosphäre entfernen können.
Lay summary

Im Zusammenhang mit der Kohlenstoffspeicherung (Sequestrierung) und -stabilisierung in Böden gibt es jedoch noch einige offene Fragen. DynaCarb wird einen landwirtschaftlichen Langzeitversuch intensiv untersuchen und dabei die folgenden Fragen beleuchten: 1.) Wie lange dauert es, bis neuer Humus im Boden stabilisiert wird und wie lange bleibt er im Boden; 2. wieviel Kohlenstoff kann für lange Zeit im Boden gespeichert werden und welche anderen Bodenbestandteile sind an dieser Stabilisierung beteiligt; 3.) wie sieht der optimale Humus aus, der lange Zeit im Boden gespeichert wird und muss man andere Nährstoffe zusätzlich geben, damit der Kohlenstoff stabilisiert werden kann; und 4.) wie lange dauert es bis man den neuen Humus wirklich genau messen kann.

DynaCarb wird wissenschaftliche Informationen über die grundlegenden Mechanismen und dynamischen Aspekte der Kohlenstoffspeicherung liefern, wertvolle Informationen über die Laufzeiten von Kohlenstoffmodellen für den Boden hinzufügen und umfangreiche Informationen für politische Interessengruppen hinzufügen, um einerseits Instrumente zur Eindämmung des Klimawandels zu entwickeln, und andererseits Leitlinien für die optimierte Düngung zur gesteigerten Kohlenstoffspeicherung und -stabilisierung an Landwirte geben zu können.

Direct link to Lay Summary Last update: 07.12.2018

Responsible applicant and co-applicants

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Associated projects

Number Title Start Funding scheme
193770 Radiocarbon Inventories of Switzerland (RICH): An integrated approach to understand the changing carbon cycle 01.10.2020 Sinergia

Abstract

Soils and soil organic matter (SOM) are the most important terrestrial sink for atmospheric CO2. Smart agricultural practices are discussed as potent options to mitigate climate change by increasing the amount of SOM and thereby removing CO2 from the atmosphere. Just recently, during the 23rd session of the United Nations Framework Conference on Climate Change (UNFCCC) in Bonn, Germany the Conference of the Parties (COP) picked up on this mechanism and launched the Koronivia Joint Work on Agriculture to address climate change issues related to agriculture. The term “improved soil carbon” is included in this document and the UNFCCC’s technical bodies are now asked to consider it in order to take the next step from science to implementation in climate change mitigation. However, several questions remain unclear in the context of carbon sequestration and stabilization in soils: 1.) It is not clear how long it takes until carbon inputs are sequestered in SOM, how fast the different SOM pools in the soil turn over, and how long the sequestered carbon is stabilized; 2.) the carbon sequestration potential of soils and especially of the stable pool is believed to be limited, but neither its driving factors nor a unified concept for its assessment are defined. Recent results point towards a strong impact of microstructure and clay mineralogy on the carbon stabilization potential of a soil; 3.) there is evidence that the quality of the input, its stoichiometry and the input of additional nutrients play an important role for the sequestration rate and level to which the C input is transferred into the stable pool; and 4.) there is a lack in statistically sound data from replicated long-term experiments that hold an extensive sample archive and recorded the fertilization quantity and quality enabling the sound assessment of management effects on the carbon sequestration dynamics, because the equilibration of SOM at a new steady-state is thought to take several decades. Therefore, it is important to understand how SOM in agricultural systems is processed, how fast it ends up in different functional pools and how long and how much can be sequestered in which pool. Our project will shed light on the sequestration, stabilization and dynamical perspective of SOM in an agriculturally managed long-term trial in Switzerland. The DOK experiment (D = biodynamic, O = bioorganic, K = conventional) is an agronomical long-term trial comparing conventional, organic, and bio-dynamic management systems since 40 years over more than 6 crop rotation cycles. The experiment is statistically well-designed with 12 replicates per treatment and holds an extensive soil sample archive covering the full period. We will focus on four treatments that differ in the quantity and quality of the organic matter input including an unfertilized treatment, one treatment receiving mineral fertilizer only, one treatment receiving organic fertilizer only and one treatment with combined organic and mineral fertilization. We will analyse this soil sample archive using physical fractionation to extract and quantify the organic matter in different density and particle size fractions to follow their development during six crop rotation cycles (Research objective 1); assess the carbon sequestration capacity of the fine particle size classes of these soils and their saturation based on fractionation data, clay mineralogy, and specific surface area as analysed by gas adsorption (Research objective 2); take advantage of bomb radiocarbon analyses using accelerator mass spectroscopy to analyse the turnover dynamics of the mineral-associated organic matter (Research objective 3); and by applying nano-scaled secondary ion mass spectrometry (NanoSIMS) as cutting-edge imaging technique to elucidate the role of just recently identified functional microdomains for carbon stabilisation and get in-depth information on their temporal stability (Research objective 4). DynaCarb will produce important scientific information on the basic mechanisms and dynamic aspects of carbon sequestration, add valuable information on turnover times for soil carbon models, and add substantial information for policy stakeholders to develop climate change mitigation tools on the one side, and dissemination guidelines to farmers for improved fertilization towards enhanced carbon sequestration and stabilization on the other side.
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