Carbon stabilization pathways in soil aggregates during long-term forest succession: Implications from δ13C signatures. (May 2023)

• Record Type: Journal Article
• Authors: Shi, Jingwei; Deng, Lei; Gunina, Anna; Alharbi, Sulaiman; Wang, Kaibo; Li, Jiwei; Liu, Yulin; Shangguan, Zhouping; Kuzyakov, Yakov
• Is Part Of: Soil biology and biochemistry. Volume 180(2023)
• Publication Date: 2023-05
• Subjects: 13C natural abundance -- Carbon stabilization pathways -- Isotopic approaches -- Plant carbon input -- Soil aggregates -- Forest restoration; Soil biochemistry -- Periodicals; Soil biology -- Periodicals; Sols -- Biochimie -- Périodiques; Sols -- Biologie -- Périodiques; Sols -- Microbiologie -- Périodiques; Bodembiologie; Biochemie; 631.46
• DOI: 10.1016/j.soilbio.2023.108988
• Languages: English
• ISSNs: 0038-0717

Abstract

Abstract: Forest restoration increases organic carbon (OC) sequestration mainly via the additional litter input and improvements in soil structure that result in biochemical and physical C stabilization over the short term. However, the pathways of long-term C stabilization in soil aggregates during forest succession are unclear. To characterize the long-term C fluxes, the aggregate-associated OC content and C flow pathways were examined over 160 years of secondary successional chronosequence from Lespedeza bicolor to Quercus liaotungensis. The contribution of plant-derived C (litters and fine roots) to aggregate-associated OC was assessed using 13 C natural abundance. The proportion of macroaggregates increased but microaggregates decreased along forest succession, and the macroaggregate-associated OC content increased from 4.6 to 28 g kg −1 during succession. The 13 C enrichment trend was common in all aggregate size classes: macroaggregates to silt and clay size classes. The maximum δ 13 C was −23‰ in the silt and clay size classes in the pioneer weed stage at 20−30 cm soil depth. The C pathways followed the trend from macroaggregates to silt and clay size classes. The intensity of the C flows decreased in the topsoil (<10 cm), but plant-derived C stocks within the aggregates increased during forest succession over the 160 years. Notably, fine roots made a greater contribution to the OC accumulation within aggregates than aboveground litter did. The microbial biomass was an important factor affecting fine root-derived C stocks in the aggregates. Concluding, this analysis of natural δ 13 C signature provides detailed insights into long-term C stabilization pathways associated with soil aggregates during forest succession. Graphical abstract: C stabilization pathway and the contribution of plant-derived C to organic carbon within aggregates during long-term forest succession. Image 1 Highlights: Forest succession increased proportion of macroaggregates and associated organic C. The δ 13 C increased in silt and clay size classes after forest succession. The intensity of the C flow in the topsoil decreased during forest succession. C flows and stabilization go from macroaggregates to silt and clay size classes. Contribution of fine roots to aggregate C was greater than that of litter.