Modeling the Potential for Carbon Removal in Agriculture: Integrating Farmer Perspectives

Sammanfattning: The overarching aim of this thesis is to provide insights into the dynamic processes governing SOC stocks and to identify viable paths for agricultural systems to contribute to climate change mitigation. By integrating current scientific knowledge of carbon sequestration in agriculture with feasible agricultural applications, this work proposes local realistic strategies for enhancing soil organic carbon (SOC) and presents a quantitative assessment of their potential for CO2 removal. The thesis underlines the importance of considering both biophysical factors and farmer participation to ensure the successful implementation and permanence of any suggested climate mitigation strategies. This thesis explores the potential of various agricultural techniques for enhanced SOC sequestration, in an agricultural landscape study site in central Sweden. It quantifies the carbon dioxide removal (CDR) potentials between various farming practices, together with the involvement of farmers. By analyzing updated databases and agricultural measures through two appended papers, this work provides insights that could inform policymakers and stakeholders in the process towards sustainable transition in agriculture and concretize climate change mitigation efforts. Paper A investigates the relationship between crop rotational diversity, soil properties, and SOC content. Utilizing data from the Swedish Agricultural Soil Inventory and Swedish Integrated Administrative and Control System, this paper quantifies and analyzes the impact of temporary perennial leys on SOC stocks and the SOC/clay ratio—an indicator of soil structure quality. The findings suggest a significant positive correlation between perennial ley frequency in crop rotations and increased SOC content, underlining the importance of diverse crop sequences for SOC sequestration. Paper B expands on the findings of Paper A and utilizes the findings in an arable landscape setting. It specifically investigates three management practices—cover crops, increased perennial ley cultivation, and biochar production and application—from a landscape perspective, assessing their potential to enhance carbon sinks. A novel landscape model of arable land incorporating these practices was developed to simulate scenarios for CDR. The results highlight the efficacy of these strategies, with the potential for a combined carbon sequestration rate of 7.1 Mg C ha -1 over 30 years when maximizing ley crops, cover crops, and biochar application.