Empowering farmers: a participatory approach to soil organic carbon assessment
Soils are key to sustain food production. An important component of soils is organic matter, which contributes to soil fertility and crop growth, and consists of about 58% carbon. This soil organic carbon also helps to fight climate change, as the more carbon is in the soil, the less in the atmosphere contributing to greenhouse effect and global warming. The primary objective of this project is to empower farmers to estimate the level of soil organic carbon content in their fields, through the assessment of soil colour. This easy and accessible method will be validated against laboratory assessment, which is usually more costly and time consuming. The project aims to develop a new, accessible method and will contribute to raising awareness on soil health and carbon sequestration that can be used to adapt farm management practices towards net zero targets.
Project lead: Lucie Büchi (Natural Resources Institute, University of Greenwich), Marcos Paradelo Perez (Natural Resources Institute, University of Greenwich)
Project collaborators: Peter Hoebe (Earthwatch Europe), Sophie Cowling (Earthwatch Europe) Alastair Leake (The Allerton Project), Aman Kanwar (City of London School for Girls), Tuan Nguyen (Natural Resources Institute, University of Greenwich), Gianluca Tozzi (Natural Resources Institute, University of Greenwich)
Findings
- Estimates of soil organic matter content are well correlated among labs but show important differences in absolute values
- It is thus crucial to report the method and protocol used when presenting data on SOC/SOM especially for assessment of changes in soil organic carbon/matter
- Using soil colour as a proxy for SOC, while not very accurate, still offer a very fast and easy way to get an estimation of SOC, especially when used to compare samples from the same field or farm.
- Working with farmers as co-interpreters of the results strengthened understanding of how soil carbon indicators relate to field history, management practices and local variability, and supports farmer-led approaches to ongoing soil health monitoring.
- Information on soil formation, land use and management has been proved to be crucial to understand SOC results across the different farms
Suggestions for further research
More research is needed to better understand differences in soil organic carbon (SOC) estimation between different methods and establish a clear protocol for reporting of those data for farmers and reports. It is also crucial to better understand how many samples, how frequently and where, are necessary to establish proper baselines and assess changes in SOC. Using soil colour to estimate soil organic matter gives a rough idea of content but more analyses are needed to establish an accurate method to create robust baseline based on those data. It is also important to better involve farmers and stakeholders in those studies to understand the practical constraints and needs of those actors.
