A spatio-temporal dataset of topsoil organic matter, plant communities and vegetation biomass, in permanent grassland ecosystems of the Massif-central

Permanent grasslands deliver key ecosystem services, notably through their role in soil organic matter (SOM) storage and nutrient cycling. However, these semi-natural ecosystems are increasingly threatened by global changes, including climate variability and management intensification, which jointly affect structure (e.g., community assembly and diversity) and function (e.g., soil carbon cycle). Despite their importance, long-term, spatially explicit datasets linking plant community properties to soil organic matter dynamics across environmental gradients remain scarce. Here, we present a comprehensive dataset collected between 2006 and 2022 across the Massif-central biogeographic region in France, encompassing 85 permanent grassland plots subjected to contrasting management practices. These include gradients of fertilization intensity (from high inputs to no fertilization), including contrasting mineral and organic fertilizer inputs, combined with mowing, grazing, mixed use, or abandonment. For each plot, we repeatedly measured soil properties focusing on soil organic matter variables (i.e., total carbon and nitrogen content, and fractionated soil organic matter pools) and associated physico-chemical parameters. The dataset integrates detailed vegetation surveys and plant functional trait data describing plant strategies along the leaf economics spectrum and morphological axes. These biological data are coupled with climate variables characterizing temperature and hydric regimes. This long-term, multi-dimensional dataset provides robust local references for soil organic matter in permanent grasslands and offers opportunities to investigate linkages between environmental drivers, plant community properties, and soil functioning. Beyond regional applications, the dataset is interoperable with global structure–function frameworks, supporting comparative analyses of grassland ecosystems dynamic under ongoing global change.