Soil CO₂ efflux, temperature, and moisture data from Mediterranean urban green spaces in Madrid, Spain (April 2023–April 2024)

This dataset contains soil respiration (CO₂ efflux), soil temperature, soil moisture, evapotranspiration, and associated climatic data collected fortnightly over one full annual cycle (April 2023–April 2024) across three urban green spaces in Madrid, Spain: Ciudad Universitaria, La Elipa, and Pinar de Conde Orgaz. Measurements were taken in four dominant ruderal plant communities present at each site: annual herbs dominated by Diplotaxis virgata (AH-D), annual grasslands dominated by Hordeum leporinum (AG-H), perennial herbs dominated by Malva spp. (PH-M), and perennial grasslands dominated by Dactylis glomerata (PG-D). Three replicate sampling points were established per plant community at each site (n = 36 sampling points in total). Soil CO₂ efflux, soil surface temperature (SST), soil surface moisture (SSM), and soil evapotranspiration (EV) were measured in situ using an infrared gas analyser (LI-8100; LI-COR Inc., Lincoln, NE, USA) with an open chamber of 20 cm diameter. Complementary hourly atmospheric temperature (AT) and atmospheric moisture (AM) data were obtained from the nearest AEMET (Agencia Estatal de Meteorología) weather stations. A rewetting index (RWi) was calculated from precipitation data and the time elapsed since the last rainfall event. This dataset supports the findings reported in: Alía, T., González-Ubierna, S., Sánchez-Jiménez, A., Abad-Calderón, R., and Casermeiro, M. A.: Soil moisture as the dominant driver of CO₂ efflux in Mediterranean urban green spaces: evidence for a Gaussian temperature response and mechanistic modelling of moisture and temperature interactions, SOIL, [volume, pages/article number], [DOI], [year].