Microbial necromass outweighs lignin in driving soil recalcitrant carbon accumulation during vegetation restoration in a subtropical karst region

1 Background and PurposeThe dataset originates from a vegetation restoration study conducted in a typical karst region of southwest China. The study aimed to uncover the mechanisms underlying soil recalcitrant organic carbon accumulation during the karst vegetation restoration, with its focus on comparing the relative contributions of plant-derived lignin and microbial-derived carbon to organic carbon stabilization. In this study, a space-for-time substitution approach was used, selecting three land-use types—cropland, shrubland, and secondary forest—representing a restoration chronosequence. A total of 54 topsoil samples (0–15 cm) were collected.2 Overview of Data ContentThe dataset contains experimental analysis results for 54 soil samples, including the following major variable groups: (1)Soil Organic Carbon FractionsTotal soil organic carbon (SOC)Labile organic carbonRecalcitrant organic carbon (ROC) (2)Plant-derived LigninLignin phenol monomers: Vanillyl (V), Syringyl (S), Cinnamyl (C)Lignin chemical stability indices: Ratios of cinnamyl to vanillyl (C/V) and syringyl to vanillyl (S/V) Lignin oxidation degree: acid-to-aldehyde ratios in vanillyl and syringyl monomers, e.g., (Ad/Al)V and (Ad/Al)S (3)Microbial Necromass CarbonAmino sugar biomarkers: Glucosamine and Muramic acidEstimated fungal and bacterial necromass carbonTotal microbial necromass carbon (4)Soil Biotic and Abiotic VariablesTotal nitrogen, total phosphorus, soil stoichiometric ratiosMicrobial biomass carbonLabile organic nitrogenSoil pH, exchangeable calcium (Ca2+) and magnesium (Mg2+)Iron and aluminum oxides (free, short-range ordered, organic-complexed forms)Soil texture: clay, silt, and sand3 Data Format and StructureFile format: Excel (.xls)Number of samples: 54Number of variables: 52 columns (including sample ID, UTM coordinates, land-use type, and all measured variables)Units:Carbon, nitrogen, and phosphorus indicators: g kg-1 or mg kg⁻¹pH: dimensionlessExchangeable cations: cmol kg-1Soil texture: percentage by weight (%)4 Brief Methods SummaryLignin analysis: Alkaline CuO oxidation followed by GC-FID detectionAmino sugars analysis: Acid hydrolysis followed by GC-FID detectionSoil physicochemical properties: Standard soil analytical methods (Carter & Gregorich, 2007)Microbial biomass carbon: Chloroform fumigation extraction method5 Suggested Data UsesThis dataset is suitable for studies related to:Soil carbon cycling and stabilization mechanismsComparative contributions of microbial vs. plant-derived carbon to stable soil carbonCarbon sequestration potential of karst ecosystemsModeling the effects of land-use change on soil organic carbon composition