In former workshops of the SOLID project, organic dairy farmers in the UK explained their difficulties in understanding and managing their soil fertility. Soil compaction is a common problem in England and the management of organic matter (OM) is a key factor to sustain soil fertility in organic systems. To increase the confidence of farmers to regularly and reliably assess their soil organic matter and soil structure, this participatory project (conducted as the MSc thesis of Ms. Coline Capron) assessed various practical assessment methods with farmers in on-farm case studies, evaluating the usefulness and relevance of different soil assessment approaches. Another objective of this work was to understand the determinants for farmers in adopting certain soil structure assessment methods (or not), for which a wide range of farmers were surveyed, interviewed and visited; and the results were compared to indicators and methods found in the literature. Here, we will present some relevant outcomes of this work.