@article{PaulBartkowskiDoenmezetal.2023, author = {Paul, Carsten and Bartkowski, Bartosz and D{\"o}nmez, Cenk and Don, Axel and Mayer, Stefanie and Steffens, Markus and Weigl, Sebastian and Wiesmeier, Martin and Wolf, Andr{\´e} and Helming, Katharina}, title = {Carbon farming: Are soil carbon certificates a suitable tool for climate change mitigation?}, series = {Journal of Environmental Management}, journal = {Journal of Environmental Management}, number = {330}, publisher = {Elsevier}, issn = {0301-4797}, doi = {10.1016/j.jenvman.2022.117142}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-8140}, pages = {11}, year = {2023}, abstract = {Increasing soil organic carbon (SOC) stocks in agricultural soils removes carbon dioxide from the atmosphere and contributes towards achieving carbon neutrality. For farmers, higher SOC levels have multiple benefits, including increased soil fertility and resilience against drought-related yield losses. However, increasing SOC levels requires agricultural management changes that are associated with costs. Private soil carbon certificates could compensate for these costs. In these schemes, farmers register their fields with commercial certificate providers who certify SOC increases. Certificates are then sold as voluntary emission offsets on the carbon market. In this paper, we assess the suitability of these certificates as an instrument for climate change mitigation. From a soils' perspective, we address processes of SOC enrichment, their potentials and limits, and options for cost-effective measurement and monitoring. From a farmers' perspective, we assess management options likely to increase SOC, and discuss their synergies and trade-offs with economic, environmental and social targets. From a governance perspective, we address requirements to guarantee additionality and permanence while preventing leakage effects. Furthermore, we address questions of legitimacy and accountability. While increasing SOC is a cornerstone for more sustainable cropping systems, private carbon certificates fall short of expectations for climate change mitigation as permanence of SOC sequestration cannot be guaranteed. Governance challenges include lack of long-term monitoring, problems to ensure additionality, problems to safeguard against leakage effects, and lack of long-term accountability if stored SOC is re-emitted. We conclude that soil-based private carbon certificates are unlikely to deliver the emission offset attributed to them and that their benefit for climate change mitigation is uncertain. Additional research is needed to develop standards for SOC change metrics and monitoring, and to better understand the impact of short term, non-permanent carbon removals on peaks in atmospheric greenhouse gas concentrations and on the probability of exceeding climatic tipping points.}, language = {en} } @article{DonmezSchmidtCileketal.2023, author = {Donmez, Cenk and Schmidt, Marcus and Cilek, Ahmet and Grosse, Meike and Paul, Carsten and Hierold, Wilfried and Helming, Katharina}, title = {Climate change impacts on long-term field experiments in Germany}, series = {Agricultural Systems}, journal = {Agricultural Systems}, number = {205}, publisher = {Elsevier}, doi = {10.1016/j.agsy.2022.103578}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-8150}, pages = {17}, year = {2023}, abstract = {CONTEXT Long-Term Field Experiments (LTEs) were implemented to study the long-term effects of different management practices, including tillage, fertilization and crop rotation under otherwise constant conditions. Climate change is expected to change these conditions, challenging interpretation of LTE data with regard to the distinction between climate change and management effects. OBJECTIVE The objective of the study was to quantify the expected, spatially differentiated changes of agroclimatic conditions for the German LTE sites as a precondition for modelling and LTE data interpretation. METHODS We developed a framework combining spatially distributed climate data and LTE metadata to identify the possible climatic changes at 247 LTE sites with experiments running for 20 years or more. The LTEs were classified using the following categories: fertilization, tillage, crop rotation, field crops or grassland, conventional or organic. We utilized climate variables (temperature, precipitation) and agroclimatic indicators (aridity, growing degree days, etc.) to compare a baseline (1971-2000) with future periods (2021-2100) under the IPCC's Shared Socio-economic Pathways (SSP). A comprehensive LTE risk assessment was conducted, based on changes in climate variables and agroclimatic indicators between baseline and future scenarios. RESULTS AND CONCLUSIONS Under the most extreme scenario (SSP585), 150 LTEs are expected to shift from humid and dry sub-humid to semi-arid conditions. Frost days in LTE areas are expected to decline by 81\%, and the growing season to lengthen by up to 92\%. The spatial differentiation of expected climate change also facilitates the identification of suitable sites for future agricultural practices and may inform the design of new LTEs. SIGNIFICANCE Our results may guide the interpretation of LTE data regarding the effect of climate change, facilitating future soil crop modelling studies with LTE data and providing information for planning new LTE sites to support future agricultural research and/or adapting management on existing LTE sites. The framework we developed can easily be transferred to LTE sites in agricultural regions worldwide to support LTE research on climate change impacts and adaptation.}, language = {en} } @article{StraussPaulDoenmezetal.2023, author = {Strauss, Veronika and Paul, Carsten and D{\"o}nmez, Cenk and L{\"o}bmann, Michael and Helming, Katharina}, title = {Sustainable soil management measures: a synthesis of stakeholder recommendations}, series = {Agronomy for Sustainable Development}, volume = {43}, journal = {Agronomy for Sustainable Development}, publisher = {Springer Nature}, doi = {10.1007/s13593-022-00864-7}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-8129}, pages = {26}, year = {2023}, abstract = {Soil degradation threatens agricultural production and soil multifunctionality. Efforts for private and public governance are increasingly emerging to leverage sustainable soil management. They require consensus across science, policy, and practice about what sustainable soil management entails. Such agreement does not yet exist to a sufficient extent in agronomic terms; what is lacking is a concise list of soil management measures that enjoy broad support among all stakeholders, and evidence on the question what hampers their implementation by farmers. We therefore screened stakeholder documents from public governance institutions, nongovernmental organizations, the agricultural industry, and conventional and organic farmer associations for recommendations related to agricultural soil management in Germany. Out of 46 recommended measures in total, we compiled a shortlist of the seven most consensual ones: (1) structural landscape elements, (2) organic fertilization, (3) diversified crop rotation, (4) permanent soil cover, (5) conservation tillage, (6) reduced soil loads, and (7) optimized timing of wheeling. Together, these measures support all agricultural soil functions, and address all major soil threats except soil contamination. Implementation barriers were identified with the aid of an online survey among farmers (n = 78). Results showed that a vast majority of farmers (> 80\%) approved of all measures. Barriers were mostly considered to be economic and in some cases technological, while missing knowledge or other factors were less relevant. Barriers were stronger for those measures that cannot be implemented in isolation, but require a systemic diversification of the production system. This is especially the case for measures that are simultaneously beneficial to many soil functions (measures 2, 3, and 4). Results confirm the need for a diversification of the agricultural system in order to meet challenges of food security and climate change. The shortlist presents the first integrative compilation of sustainable soil management measures supporting the design of effective public or private governance.}, language = {en} }