{"type": "FeatureCollection", "features": [{"id": "10.1111/ejss.13379", "type": "Feature", "geometry": null, "properties": {"updated": "2026-04-13T16:19:18Z", "type": "Journal Article", "created": "2023-05-10", "title": "Limitations of farm management data in analyses of decadal changes in SOC stocks in the Danish soil\u2010monitoring network", "description": "Abstract

Changes in soil organic carbon (SOC) storage in agricultural land are an important part of the Land Use, Land\uffe2\uff80\uff90Use Change and Forestry component of national greenhouse gas emission inventories. Furthermore, as climate mitigation strategies and incentives for carbon farming are being developed, accurate estimates of SOC stocks are essential to verify any management\uffe2\uff80\uff90induced changes in SOC. Based on agricultural mineral soils in the Danish soil\uffe2\uff80\uff90monitoring network, we analysed management effects on SOC stocks using data from the two most recent surveys (2009 and 2019). Between 2009 and 2019, the average increase in SOC stock was 1.2\uffe2\uff80\uff89Mg C\uffe2\uff80\uff89ha \uffe2\uff88\uff921 for 0\uffe2\uff80\uff9350\uffe2\uff80\uff89cm despite a loss of 1.2\uffe2\uff80\uff89Mg\uffe2\uff80\uff89C\uffe2\uff80\uff89ha \uffe2\uff88\uff921 from the topsoil (0\uffe2\uff80\uff9325\uffe2\uff80\uff89cm), stressing the importance of including deeper soil layers in soil\uffe2\uff80\uff90monitoring networks. Comparing all four national surveys (1986, 1997, 2009, 2019), the mean SOC stock of mineral soils in Denmark appears stable. The change in SOC stock between 2009 and 2019 was analysed in detail in relation to management practices as reported by farmers. We found that the effects of single management factors were difficult to isolate from co\uffe2\uff80\uff90varying factors including soil parameters and that the use of farm management data to explain changes in SOC stocks observed in soil\uffe2\uff80\uff90monitoring networks appears limited. Uncertainty in SOC stock estimates also arises from low sampling frequency and statistical challenges related to regression to the mean. However, repeated stock measurements at decadal intervals still represent a benchmark for the overall development in regional and national SOC storage, as affected by actual farm management. There is growing international interest in better managing soils to increase soil organic carbon (SOC) content to contribute to climate change mitigation, to enhance resilience to climate change and to underpin food security, through initiatives such as international \uffe2\uff80\uff984p1000\uffe2\uff80\uff99 initiative and the FAO's Global assessment of SOC sequestration potential (GSOCseq) programme. Since SOC content of soils cannot be easily measured, a key barrier to implementing programmes to increase SOC at large scale, is the need for credible and reliable measurement/monitoring, reporting and verification (MRV) platforms, both for national reporting and for emissions trading. Without such platforms, investments could be considered risky. In this paper, we review methods and challenges of measuring SOC change directly in soils, before examining some recent novel developments that show promise for quantifying SOC. We describe how repeat soil surveys are used to estimate changes in SOC over time, and how long\uffe2\uff80\uff90term experiments and space\uffe2\uff80\uff90for\uffe2\uff80\uff90time substitution sites can serve as sources of knowledge and can be used to test models, and as potential benchmark sites in global frameworks to estimate SOC change. We briefly consider models that can be used to simulate and project change in SOC and examine the MRV platforms for SOC change already in use in various countries/regions. In the final section, we bring together the various components described in this review, to describe a new vision for a global framework for MRV of SOC change, to support national and international initiatives seeking to effect change in the way we manage our soils.There is growing international interest in better managing soils to increase soil organic carbon (SOC) content to contribute to climate change mitigation, to enhance resilience to climate change and to underpin food security, through initiatives such as international \uffe2\uff80\uff984p1000\uffe2\uff80\uff99 initiative and the FAO's Global assessment of SOC sequestration potential (GSOCseq) programme. Since SOC content of soils cannot be easily measured, a key barrier to implementing programmes to increase SOC at large scale, is the need for credible and reliable measurement/monitoring, reporting and verification (MRV) platforms, both for national reporting and for emissions trading. Without such platforms, investments could be considered risky. In this paper, we review methods and challenges of measuring SOC change directly in soils, before examining some recent novel developments that show promise for quantifying SOC. We describe how repeat soil surveys are used to estimate changes in SOC over time, and how long\uffe2\uff80\uff90term experiments and space\uffe2\uff80\uff90for\uffe2\uff80\uff90time substitution sites can serve as sources of knowledge and can be used to test models, and as potential benchmark sites in global frameworks to estimate SOC change. We briefly consider models that can be used to simulate and project change in SOC and examine the MRV platforms for SOC change already in use in various countries/regions. In the final section, we bring together the various components described in this review, to describe a new vision for a global framework for MRV of SOC change, to support national and international initiatives seeking to effect change in the way we manage our soils.