Data & scripts belonging with MSc Thesis: "Exploring Crop Rotational Diversity and Its Role in Enhancing Soil Organic Carbon in European Agroecosystems"

The current shift towards increased intensification and specialization of European agricultural systems may lead to short-term yield benefits, but poses a threat to maintaining yield, soil health and economic stability in the long-term. Diverse cropping systems are expected to increase soil health and maintain yield, even under adverse climate conditions. Crop rotation is an example of such a diverse cropping system, which has been widely used all over Europe for centuries. Yet, there is a lack of studies on the spatial and temporal variability of crop rotational diversity (CRD) across Europe. In this research, 6226 observations from the LUCAS database are be combined with farm management data from the Farm Accountancy Data Network (FADN) collected over a time span of 11 years, as well as with climatic and socioeconomic variables. Based on this combined dataset, a large-scale analysis on the spatial and temporal variability of CRD in Europe was carried out, and the effect of increasing CRD on SOC stocks was investigated using Random Forest modelling. Current levels of CRD in Europe were found to be highest in Central Europe and lowest in marginal regions (e.g. arid or mountainous). Overall, levels of CRD have been increasing between 2009-2020. The Random Forest model for explaining variability in CRD had a high model performance, with organic farming, farm size and climatic factors being the most important predictors. The Random Forest models for explaining SOC stock changes had a low model performance, likely caused by high variability and noise within the LUCAS data. Soil OC and N content were the most important significant predictors. The low model performances and lack of established direct correlations between ΔCRD and ΔSOC means that the effects of varying levels of species diversity in rotational systems still remains unclear. OC data from LUCAS should be further refined in future research, in order to reduce noise and uncertainty and for clearing up what still remains unknown about the effects of CRD on SOC stocks, so that concrete policy and management recommendations can be made to help secure healthy soils and sufficient food production, even in a changing climate.