Figure depicting the main data sources, analyses and hypotheses of Work Package (WP) 1. A: The field site of the Main Experiment in the Jena Experiment. B: Tentative timepoints of sampling campaigns. This WP will build on three unique datasets to explore short-term and long-term effects of plant diversity on the stability of soil (microbial) properties in the Main Experiment (yearly measurements of soil microbial properties; 2003-2024), ΔBEF Experiment (yearly measurements of soil microbial properties; 2017-2023) and seasonal measurements of focal soil processes in plots of the Main Experiment in 2024. Illustration of the hypotheses (C) that plant diversity effects on the magnitude and stability of soil microbial properties increase over time and (D) that the temporal stability of soil microbial properties can be better predicted, based on short-term resistance than on recovery.