Rapid loss of organic carbon and soil structure in mountainous grassland topsoils induced by simulated climate change
Noelia Garcia-Franco,
Martin Wiesmeier,
Vincent Buness,
Bernd J. Berauer,
Max A. Schuchardt,
Anke Jentsch,
Marcus Schlingmann,
Diana Andrade-Linares,
Benjamin Wolf,
Ralf Kiese,
Michael Dannenmann,
Ingrid Kögel-Knabner
Affiliations
Noelia Garcia-Franco
Chair of Soil Science, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany; Corresponding author.
Martin Wiesmeier
Chair of Soil Science, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany; Bavarian State Research Center for Agriculture, Freising, Germany
Vincent Buness
Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
Bernd J. Berauer
Institute of Landscape and Plant Ecology, Department of Plant Ecology, University of Hohenheim, Ottilie-Zeller-Weg 2, 70599 Stuttgart, Germany
Max A. Schuchardt
Department of Disturbance Ecology, University of Bayreuth, Bayreuth, Germany
Anke Jentsch
Department of Disturbance Ecology, University of Bayreuth, Bayreuth, Germany
Marcus Schlingmann
Agricultural Center for cattle production, grassland management, dairy processing, wildlife research and fisheries Baden-Wuerttemberg (LAZBW), Aulendorf, Germany
Diana Andrade-Linares
Research Unit Comparative Microbiome Analysis, Helmholtz Zentrum München, Ingolstädter Landstraße 1, D-85764 Neuherberg, Germany
Benjamin Wolf
Karlsruhe Institute of Technology, Institute of Meteorology and Climate Research I (IMK-IFU), Garmisch-Partenkirchen, Germany
Ralf Kiese
Karlsruhe Institute of Technology, Institute of Meteorology and Climate Research I (IMK-IFU), Garmisch-Partenkirchen, Germany
Michael Dannenmann
Karlsruhe Institute of Technology, Institute of Meteorology and Climate Research I (IMK-IFU), Garmisch-Partenkirchen, Germany
Ingrid Kögel-Knabner
Chair of Soil Science, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany; Institute for Advanced Study, Technical University Munich, Garching, Germany
Mountainous grassland soils are considered one of the most unique biological hotspots, rich in organic carbon (OC). At the same time, they are exposed to great threats, as climate warming is more pronounced in mountainous regions than in lowland areas. In this study, we assessed the effect of simulated warming (+1K, +2K, and + 3 K) on OC stocks and soil structure in grassland soils of the Northern Limestone Alps in Germany by translocating plant-soil mesocosms from high- (1260 m a.s.l., Rendzic Phaeozem) and mid- (860 m a. s. l., Haplic Cambisol) to low-elevation (600 m a.s.l). Plant-soil mesocosms were exposed to both extensive and intensive grassland management practices. Four years after translocation, we observed a rapid decrease of topsoil SOC stocks under intensive (−1.0 t C ha yr−1) and extensive management (-2.2 t C ha yr−1), under the highest temperature increase. Intensive management with about 1 t C ha−1 yr−1 higher manure C return than extensive management (1.6 vs. 0.8 t C ha−1 yr−1 intensive and extensive, respectively) may explain the difference in SOC losses between different management treatments. Under both management practices, the loss of SOC was mainly associated with a decrease of large macroaggregates, at both management practices. In addition, different aggregate specific OC loss rates resulted in an altered distribution of OC among the aggregate size classes. Our study provides evidence that simulated climate change induced a rapid and substantial decline of SOC in mountainous, OC-rich grassland soils, which may be attributed to decreased physical OC protection within large macroaggregates. Optimized grassland management in form of increased application of organic fertilizers could only partially offset the SOC loss by improved formation of small macroaggregates.
