Labile carbon inputs offset nitrogen-induced soil aggregate destabilization via enhanced growth of saprophytic fungi in a meadow steppe
Ruonan Zhao,
Yakov Kuzyakov,
Haiyang Zhang,
Zhirui Wang,
Tianpeng Li,
Lingyu Shao,
Liangchao Jiang,
Ruzhen Wang,
Maihe Li,
Osbert Jianxin Sun,
Yong Jiang,
Xingguo Han
Affiliations
Ruonan Zhao
State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; University of Chinese Academy of Sciences, Beijing 100049, China; Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, CH-8903 Birmensdorf, Switzerland; Erguna Forest-Steppe Ecotone Ecosystem Research Station, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
Yakov Kuzyakov
Department of Soil Science of Temperate Ecosystems, Department of Agricultural Soil Science, University of Goettingen, 37077 Göttingen, Germany; Peoples Friendship University of Russia (RUDN University), 117198 Moscow, Russia
Haiyang Zhang
School of Life Sciences, Hebei University, Baoding 071002, China
Zhirui Wang
Erguna Forest-Steppe Ecotone Ecosystem Research Station, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
Tianpeng Li
Institute of Landscape Ecology, University of Muenster, 48149 Muenster, Germany; Erguna Forest-Steppe Ecotone Ecosystem Research Station, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
Lingyu Shao
State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; University of Chinese Academy of Sciences, Beijing 100049, China; Erguna Forest-Steppe Ecotone Ecosystem Research Station, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
Liangchao Jiang
School of Life Sciences, Hebei University, Baoding 071002, China; Erguna Forest-Steppe Ecotone Ecosystem Research Station, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
Ruzhen Wang
School of Life Sciences, Hebei University, Baoding 071002, China; Erguna Forest-Steppe Ecotone Ecosystem Research Station, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
Maihe Li
School of Life Sciences, Hebei University, Baoding 071002, China; Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, CH-8903 Birmensdorf, Switzerland
Osbert Jianxin Sun
School of Life Sciences, Hebei University, Baoding 071002, China; School of Ecology and Nature Conservation, Beijing Forestry University, Beijing 100083, China
Yong Jiang
School of Life Sciences, Hebei University, Baoding 071002, China; Erguna Forest-Steppe Ecotone Ecosystem Research Station, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
Xingguo Han
State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; University of Chinese Academy of Sciences, Beijing 100049, China; Corresponding author at: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Xiangshan, Beijing 100083, China.
The formation and stability of soil aggregates affect plant growth, carbon sequestration, and many other physiological and biogeochemical processes. Aggregates may be destabilized by nitrogen (N) deposition due to decreased inputs of binding materials; however, the legacy effects of which are unknown. An increase in labile carbon (C) input could mitigate the negative impacts of N addition on soil aggregate stability through the improvement of soil physical, chemical and biological conditions. Using a field experiment with the addition of NH4NO3 at multiple levels in a meadow steppe, we terminated the addition of N at the sixth year and shifted to applying labile C in the form of sucrose at three levels (C-0, C-200, and C-2000 g C m−2 y−1) to soil for two years. Then we examined the aggregate size distribution and the associated soil properties. The high historical N addition rates decreased the proportion of macroaggregates (>2000 μm) and increased microaggregates (<250 μm), leading to a reduction in the mean weight diameter (MWD), an index of soil aggregation stability. Labile C input offset the legacy effects of N addition on soil aggregates hierarchy and reversed the N-induced changes in MWD. Labile C input did not affect soil pH and exchangeable Ca2+, but increased the microbial biomass carbon (MBC) and the relative abundance of soil saprotrophic fungi (SSF); whilst the C-200 increased the relative abundance of arbuscular mycorrhizal fungi (AMF) only at low N addition rates (<N20) in comparison with that of the C-0. Analysis with the structural equation model (SEM) revealed the positive effects of labile C input on soil aggregate stability mainly by increasing the relative abundance of SSF across all N addition rates. The results of this study clearly demonstrate the effective role of short-term (2 years) labile C input in offsetting the N-caused soil aggregate instability in the meadow steppe by promoting soil microbial activity.
