https://doi.org/10.5061/dryad.b5mkkwhp0

Files and variables

File: Willard_GCB_2024_processed_data.csv

Description: 

Variables

• UniqueObsCodeThreePool: Code to denote each unique datapoint featuring: Study ID, simplified ecosystem, USDA soil order, Treatment name, fractionation type (fLF, oLF, mSOC), and topsoil or subsoil
• Study_ID: Author name and published year
• Citation: Author name, published year, journal name, and edition information
• Year_sampled: Sampled year
• Field_or_Lab: Study system
• Latitude: Latitude of sampled location
• Longitude: Longitude of sampled location
• Country: Country of sampled location
• Elevation: Sample elevation
• Ecosystem_type: Ecosystem of sampled location
• Ecosystem_simplified: Simplified ecosystem of sampled location
• Crop_or_forest_type_reported: Cropping or forest type of sampled location
• Cropland_addition: Nutrient addition of sampled soil
• Cropland_addition_N.kg.ha.yr: Inorganic nitrogen addition of sampled soil in units of kg/ha/yr.
• Cropland_addition_Manure.Mg.ha.yr: Manure addition of sampled location in units of kg/ha/yr.
• Cropland_tillage: Tillage regimen of sampled soil
• Soil_order_reported: Reported soil order including USDA and World Reference Base
• Soil_order_simplified: USDA simplified soil order
• Soil_texture: Reported soil texture
• Horizon: Sampled soil horizon
• Soil_volume: Calculated soil volume (100cm *100cm * soil depth)
• Top_depth: Top soil depth (cm)
• bottom_depth: Bottom soil depth (cm)
• Soil_pH_reported: Reported soil pH
• Treatment: Treatment name
• Rotation: Reported cropland rotation information
• Fraction_reported: SOC fraction reported in study
• Fraction_harmonized: Harmonized fraction name for dataset unification
• Floatation_density: Reported density flotation in units of g/cm^3
• Two_pool: Harmonized fraction for two pool sorting (HF and LF)
• Three_pool: Harmonized fraction for three pool sorting (fLF, oLF, mSOC; note manuscript uses terms fPOC, oPOC, and mSOC to convey geochemical characteristics)
• Method_used_C: Reported methodology used to differentiate SOC fraction
• Primary_C_pool: Primary C pool data reported from study: used to calculate data found in C_stock_for_analysis_three_pool. Obsoleted in Willard_GCB_2024_processed_data.csv due to data recombining.
• Units_Primary: Units of primary data (e.g.: g/kg, %)
• Units_Primary_Annotated: Annotation of primary units
• Secondary_C_pool: Secondary C pool data reported from study (used to calculate to g m^2) : used to calculate data found in C_stock_for_analysis_three_pool. Obsoleted in Willard_GCB_2024_processed_data.csv due to data recombining
• Units_Secondary: Units of secondary data (e.g.: g/kg, %)
• MAT_reported: Mean annual temperature (degrees Celsius) reported (used when available)
• MAP_reported: Mean annual precipitation (mm) reported (used when available)
• MAT_added: Mean annual temperature (degrees Celsius) extracted from Terra Climate
• MAP_added: Mean annual precipitation (mm) extracted from Terra Climate
• MAT_used: Mean annual temperature (degrees Celsius) used
• MAP_used: Mean annual precipitation (mm) used
• T_PH_H2O: HWSD topsoil pH; extracted from Harmonized World Soil Database
• S_PH_H2O: HWSD subsoil pH; extracted from Harmonized World Soil Database
• T_CLAY: HWSD topsoil clay percentage; extracted from Harmonized World Soil Database
• S_CLAY: HWSD subsoil clay percentage; extracted from Harmonized World Soil Database
• T_BULK_DEN: HWSD topsoil bulk density (g/cm^3); extracted from Harmonized World Soil Database
• S_BULK_DEN: HWSD subsoil bulk density (g/cm^3); extracted from Harmonized World Soil Database
• BD_reported: Bulk density reported (g cm^3; used when available)
• BD_used: Bulk density used (g cm^3)
• Calculated_C_pool: Calculated C pool size (Primary_C_pool multiplied by Secondary_C_pool C * BD_used * summed_vol where appropriate to units of g m^2; calculated prior to combining along UniqueObsCodeThreePool)
• layer: topsoil (0-30cm) or subsoil (31+cm)
• UniqueObsCodeTwoPool: Code to denote each unique datapoint featuring: Study ID, simplified ecosystem, USDA soil order, Treatment name, fractionation type (HF or LF), and topsoil or subsoil
• C_stock_for_analysis_three_pool: Combined C pool along UniqueObsCodeThreePool: used as response C pool data in manuscript models and in units of g m^2
• PH_three_pool: Combined soil pH along UniqueObsCodeThreePool
• summed_vol: summed soil volume along UniqueObsCodeThreePool and in units of cm^3

Note: NA’s denote unreported data from publications

File: Willard_GCB_2024_raw_data.csv

Description: 

Variables

• Study_ID: Author name and published year
• Citation: Author name, published year, journal name, and edition information
• Year_sampled: Sampled year
• Field_or_Lab: Study system
• Latitude: Latitude of sampled location
• Longitude: Longitude of sampled location 
• Country: Country of sampled location
• Elevation: Sample elevation
• Ecosystem_type: Ecosystem of sampled location
• Ecosystem_simplified: Simplified ecosystem of sampled location
• Crop_or_forest_type_reported: Cropping or forest type of sampled location
• Cropland_addition: Nutrient addition of sampled soil
• Cropland_addition_N kg/ha/yr: Inorganic nitrogen addition of sampled soil in units of kg/ha/yr.
• Cropland_addition_Manure Mg ha yr: Manure addition of sampled location in units of kg/ha/yr.
• Cropland_tillage: Tillage regimen of sampled soil
• Soil_order_reported: Reported soil order including USDA and World Reference Base
• Soil_order_simplified: USDA simplified soil order
• Soil_texture: Reported soil texture
• Horizon: Sampled soil horizon
• Soil_volume: Calculated soil volume (100cm100cm * soil depth)
• Top_depth: Top soil depth (cm)
• bottom_depth: Bottom soil depth (cm)
• Soil_pH_reported: Reported soil pH
• Treatment: Treatment name
• Rotation: Reported cropland rotation information
• Fraction_reported: SOC fraction reported in study
• Fraction_harmonized: Harmonized fraction name for dataset unification
• Floatation_density: Reported density flotation in units of g/cm^3
• Two_pool: Harmonized fraction for two pool sorting (HF and LF)
• Three_pool: Harmonized fraction for three pool sorting (fLF, oLF, mSOC; note manuscript uses terms fPOC, oPOC, and mSOC to convey geochemical characteristics)
• Method_used_C: Reported methodology used to differentiate SOC fraction
• Primary_C_pool: Primary C pool data reported from study: used to calculate data found in C_stock_for_analysis_three_pool. Obsoleted in Processed_data file due to data recombining.
• Units_Primary: Units of primary data (e.g.: g/kg, %)
• Units_Primary_Annotated: Annotation of primary units
• Secondary_C_pool: Secondary C pool data reported from study (used to calculate to g m^2) : used to calculate data found in C_stock_for_analysis_three_pool. Obsoleted in Processed_data file due to data recombining.
• Units_Secondary: Units of secondary data (e.g.: g/kg, %)
• MAT_reported: Mean annual temperature (degrees Celsius) reported (used when available)
• MAP_reported: Mean annual precipitation (mm) reported (used when available)
• MAT_added: Mean annual temperature (degrees Celsius) extracted from Terra Climate
• MAP_added: Mean annual precipitation (mm) extracted from Terra Climate
• MAT_used: Mean annual temperature (degrees Celsius) used 
• MAP_used: Mean annual precipitation (mm) used
• T_PH_H2O: HWSD topsoil pH; extracted from Harmonized World Soil Database
• S_PH_H2O: HWSD subsoil pH; extracted from Harmonized World Soil Database
• T_CLAY: HWSD topsoil clay percentage; extracted from Harmonized World Soil Database
• S_CLAY: HWSD subsoil clay percentage; extracted from Harmonized World Soil Database
• T_BULK_DEN: HWSD topsoil bulk density (g/cm^3); extracted from Harmonized World Soil Database
• S_BULK_DEN:HWSD subsoil bulk density (g/cm^3); extracted from Harmonized World Soil Database
• BD_reported: Bulk density reported (g cm^3; used when available)
• BD_used: Bulk density used (g cm^3)
• Calculated_C_pool: Calculated C pool size (Primary_C_pool multiplied by Secondary_C_pool C * BD_used * summed_vol where appropriate to units of g m^2; calculated prior to combining along UniqueObsCodeThreePool) and in units of g m^2
• layer: topsoil (0-30cm) or subsoil (31+cm)

Note: NA’s denote unreported data from publications

Code/software

Data analysis was done in R (version 4.3.1). Packages for statistics and graphing included: lme4, lmerTest, MuMIn, plotrix, stringr, dplyr, tidyverse, ggplot2, and lsmeans.

Access information

Data was derived from the following sources:

• Provided is the list of publications from which data was extracted and utilized within the analysis:

  1.         Alcántara, V., Don, A., Vesterdal, L., Well, R. & Nieder, R. Stability of buried carbon in deep-ploughed forest and cropland soils - Implications for carbon stocks. Sci Rep 7, 1–12 (2017).

  2.         Alhameid, A., Ibrahim, M., Kumar, S., Sexton, P. & Schumacher, T. E. Soil Organic Carbon Changes Impacted by Crop Rotational Diversity under No-Till Farming in South Dakota, USA. Soil Science Society of America Journal 81, 868–877 (2017).

  3.         Alvarez, C. R., Alvarez, R., Grigera, M. S. & Lavado, R. S. Associations between organic matter fractions and the active soil microbial biomass. Soil Biol Biochem 30, 767–773 (1998).

  4.         Alvarez, R. & Alvarez, C. R. Soil Organic Matter Pools and Their Associations with Carbon Mineralization Kinetics. Soil Science Society of America Journal 64, 184–189 (2000).

  5.         Álvaro-Fuentes, J. et al. Soil Aggregation and Soil Organic Carbon Stabilization: Effects of Management in Semiarid Mediterranean Agroecosystems. Soil Science Society of America Journal 73, 1519–1529 (2009).

  6.         Amado, T. J. C. et al. Potential of Carbon Accumulation in No‐Till Soils with Intensive Use and Cover Crops in Southern Brazil. J Environ Qual 35, 1599–1607 (2006).

  7.         Anaya, C. A. & Huber-Sannwald, E. Long-term soil organic carbon and nitrogen dynamics after conversion of tropical forest to traditional sugarcane agriculture in East Mexico. Soil Tillage Res 147, 20–29 (2015).

  8.         Aoyama, M. DRIFT spectroscopy combined with sodium hypochlorite oxidation reveals different organic matter characteristics in density-size fractions of organically managed soils. Can J Soil Sci 96, 317–327 (2016).

  9.         Artemyeva, Z. S., Žigová, А., Kirillova, N. P. & Šťastný, M. Dynamics of organic matter in soils following a change in landuse on permo-carboniferous rocks in the ČeskÝ brod area (Czech Republic). Acta Geodynamica et Geomaterialia 15, 339–348 (2018).

  10.       Baisden, W. T., Amundson, R., Cook, A. C. & Brenner, D. L. Turnover and storage of C and N in five density fractions from California annual grassland surface soils. Global Biogeochem Cycles 16, 1–16 (2002).

  11.       Besnard, E., Chenu, C., Balesdent, J., Puget, P. & Arrouays, D. Fate of particulate organic matter in soil aggregates during cultivation. Eur J Soil Sci 47, 495–503 (1996).

  12.       Bhattacharyya, R., Tuti, M. D., Kundu, S., Bisht, J. K. & Bhatt, J. C. Conservation Tillage Impacts on Soil Aggregation and Carbon Pools in a Sandy Clay Loam Soil of the Indian Himalayas. Soil Science Society of America Journal 76, 617–627 (2012).

  13.       Bischoff, N. et al. Land-use change under different climatic conditions: Consequences for organic matter and microbial communities in Siberian steppe soils. Agric Ecosyst Environ 235, 253–264 (2016).

  14.       Blackwood, C. B. & Paul, E. A. Eubacterial community structure and population size within the soil light fraction, rhizosphere, and heavy fraction of several agricultural systems. Soil Biol Biochem 35, 1245–1255 (2003).

  15.       Boone, R. D., Sollins, P. & Cromack, K. Stand and Soil Changes Along A Mountain Hemlock Death and Regrowth Sequence. Ecology 69, 714–722 (1988).

  16.       Boone, R. D. Light-fraction soil organic matter: origin and contribution to net nitrogen mineralization. Soil Biol Biochem 26, 1459–1468 (1994).

  17.       Bosshard, C. et al. Incorporation of Nitrogen‐15‐Labeled Amendments into Physically Separated Soil Organic Matter Fractions. Soil Science Society of America Journal 72, 949–959 (2008).

  18.       Breulmann, M. et al. Short-term bioavailability of carbon in soil organic matter fractions of different particle sizes and densities in grassland ecosystems. Science of the Total Environment 497–498, 29–37 (2014).

  19.       Breulmann, M., Boettger, T., Buscot, F., Gruendling, R. & Schulz, E. Carbon storage potential in size-density fractions from semi-natural grassland ecosystems with different productivities over varying soil depths. Science of the Total Environment 545–546, 30–39 (2016).

  20.       Brodowski, S., John, B., Flessa, H. & Amelung, W. Aggregate-occluded black carbon in soil. Eur J Soil Sci 57, 539–546 (2006).

  21.       Cadisch, G., Imhof, H., Urquiaga, S., Boddey, R. M. & Giller, K. E. Carbon turnover (δ13C) and nitrogen mineralization potential of particulate light soil organic matter after rainforest clearing. Soil Biol Biochem 28, 1555–1567 (1996).

  22.       Chen, Y. et al. Changes in soil carbon pools and microbial biomass from urban land development and subsequent post-development soil rehabilitation. Soil Biol Biochem 66, 38–44 (2013).

  23.       Chen, Z. J. et al. Addition of nitrogen enhances stability of soil organic matter in a temperate forest. Eur J Soil Sci 68, 189–199 (2017).

  24.       Cheng, X., Luo, Y., Xu, X., Sherry, R. & Zhang, Q. Soil organic matter dynamics in a North America tallgrass prairie after 9 yr of experimental warming. Biogeosciences 8, 1487–1498 (2011).

  25.       Chimento, C., Almagro, M. & Amaducci, S. Carbon sequestration potential in perennial bioenergy crops: The importance of organic matter inputs and its physical protection. GCB Bioenergy 8, 111–121 (2016).

  26.       Compton, J. E. & Boone, R. D. Long-term impacts of agriculture on soil carbon and nitrogen in New England forests. Ecology 81, 2314–2330 (2000).

  27.       Conant, R. T., Six, J. & Paustian, K. Land use effects on soil carbon fractions in the southeastern United States. II. Changes in soil carbon fractions along a forest to pasture chronosequence. Biol Fertil Soils 40, 194–200 (2004).

  28.       Cong, W., Ren, T. & Li, B. Assessing the impact of afforestation on soil organic C sequestration by means of sequential density fractionation. PLoS One 10, 1–20 (2015).

  29.       Cromack, K., Miller, R. E., Anderson, H. W., Helgerson, O. T. & Smith, R. B. Soil Carbon and Nutrients in a Coastal Oregon Douglas‐Fir Plantation with Red Alder. Soil Science Society of America Journal 63, 232–239 (1999).

  30.       Crow, S. E., Reeves, M., Schubert, O. S. & Sierra, C. A. Optimization of method to quantify soil organic matter dynamics and carbon sequestration potential in volcanic ash soils. Biogeochemistry 123, 27–47 (2015).

  31.       Crow, S. E., Deem, L. M., Sierra, C. A. & Wells, J. M. Belowground carbon dynamics in tropical perennial C4 grass agroecosystems. Front Environ Sci 6, 1–12 (2018).

  32.       Crow, S. E. & Sierra, C. A. Dynamic, Intermediate Soil Carbon Pools May Drive Future Responsiveness to Environmental Change. J Environ Qual 47, 607–616 (2018).

  33.       Curtin, D., Beare, M. H., Qiu, W. & Sharp, J. Does Particulate Organic Matter Fraction Meet the Criteria for a Model Soil Organic Matter Pool? Pedosphere 29, 195–203 (2019).

  34.       Cusack, D. F. et al. Decadal-scale litter manipulation alters the biochemical and physical character of tropical forest soil carbon. Soil Biol Biochem 124, 199–209 (2018).

  35.       Degryze, S. et al. Soil organic carbon pool changes following land-use conversions. Glob Chang Biol 10, 1120–1132 (2004).

  36.       Del Galdo, I., Six, J., Peressotti, A. & Cotrufo, M. F. Assessing the impact of land-use change on soil C sequestration in agricultural soils by means of organic matter fractionation and stable C isotopes. Glob Chang Biol 9, 1204–1213 (2003).

  37.       Del Galdo, I., Oechel, W. C. & Francesca Cotrufo, M. Effects of past, present and future atmospheric CO2 concentrations on soil organic matter dynamics in a chaparral ecosystem. Soil Biol Biochem 38, 3235–3244 (2006).

  38.       DeMarco, J., Filley, T. & Throop, H. L. Patterns of woody plant-derived soil carbon losses and persistence after brush management in a semi-arid grassland. Plant Soil 406, 277–293 (2016).

  39.       Demyan, M. S. et al. Use of specific peaks obtained by diffuse reflectance Fourier transform mid-infrared spectroscopy to study the composition of organic matter in a Haplic Chernozem. Eur J Soil Sci 63, 189–199 (2012).

  40.       Deng, W., Wu, W., Wang, H., Luo, W. & Kimberley, M. O. Temporal dynamics of iron-rich, tropical soil organic carbon pools after land-use change from forest to sugarcane. J Soils Sediments 9, 112–120 (2009).

  41.       Doetterl, S. et al. Aboveground vs. belowground carbon stocks in African tropical lowland rainforest: Drivers and implications. PLoS One 10, 1–14 (2015).

  42.       Dondini, M., Van Groenigen, K.-J., Del Galdo, I. & Jones, M. B. Carbon sequestration under Miscanthus : a study of 13 C distribution in soil aggregates. GCB Bioenergy 1, 321–330 (2009).

  43.       Dong, X., Guan, T., Li, G., Lin, Q. & Zhao, X. Long-term effects of biochar amount on the content and composition of organic matter in soil aggregates under field conditions. J Soils Sediments 16, 1481–1497 (2016).

  44.       Dou, X., Xu, X., Shu, X., Zhang, Q. & Cheng, X. Shifts in soil organic carbon and nitrogen dynamics for afforestation in central China. Ecol Eng 87, 263–270 (2016).

  45.       Dyck, M., Malhi, S. S., Nyborg, M. & Puurveen, D. Effects of Short-term Tillage of a Long-term No-Till Land on Quantity and Quality of Organic C and N in Two Contrasting Soil Types. Sustainable Agriculture Research 5, 43 (2016).

  46.       Echeverría, M. E., Markewitz, D., Morris, L. A. & Hendrick, R. L. Soil Organic Matter Fractions under Managed Pine Plantations of the Southeastern USA. Soil Science Society of America Journal 68, 950–958 (2004).

  47.       Eckmeier, E. et al. Preservation of fire-derived carbon compounds and sorptive stabilisation promote the accumulation of organic matter in black soils of the Southern Alps. Geoderma 159, 147–155 (2010).

  48.       Egli, M. et al. Effect of north and south exposure on organic matter in high Alpine soils. Geoderma 149, 124–136 (2009).

  49.       Entry, J. A. & Emmingham, W. H. Influence of forest age on forms of carbon in Douglas-fir soils in the Oregon Coast Range. Canadian Journal of Forest Research 28, 390–395 (1998).

  50.       Fang, Y., Singh, B. P., Luo, Y., Boersma, M. & Van Zwieten, L. Biochar carbon dynamics in physically separated fractions and microbial use efficiency in contrasting soils under temperate pastures. Soil Biol Biochem 116, 399–409 (2018).

  51.       Garcia-Franco, N., Albaladejo, J., Almagro, M. & Martínez-Mena, M. Beneficial effects of reduced tillage and green manure on soil aggregation and stabilization of organic carbon in a Mediterranean agroecosystem. Soil Tillage Res 153, 66–75 (2015).

  52.       Garten, C. T., Post, W. M., Hanson, P. J. & Cooper, L. W. Forest Soil Carbon Inventories and Dynamics along an Elevation Gradient in the Southern Appalachian Mountains. Biogeochemistry 45, 115–145 (1999).

  53.       Giannetta, B., Plaza, C., Vischetti, C., Cotrufo, M. F. & Zaccone, C. Distribution and thermal stability of physically and chemically protected organic matter fractions in soils across different ecosystems. Biol Fertil Soils 54, 671–681 (2018).

  54.       Gillabel, J., Denef, K., Brenner, J., Merckx, R. & Paustian, K. Carbon Sequestration and Soil Aggregation in Center-Pivot Irrigated and Dryland Cultivated Farming Systems. Soil Science Society of America Journal 71, 1020–1028 (2007).

  55.       Glaser, B., Balashov, E., Haumaier, L., Guggenberger, G. & Zech, W. Black carbon in density fractions of anthropogenic soils of .pdf. Org Geochem 31, 669–678 (2000).

  56.       Golchin, A., Oades, J. M., Skjemstad, J. O. & Clarke, P. Structural and dynamic properties of soil organic matter as reflected by 13c natural abundance, pyrolysis mass spectrometry and solid-state 13c nmr spectroscopy in density fractions of an oxisol under forest and pasture. Australian Journal of Soil Research 33, 59–76 (1995).

  57.       Grandy, A. S. & Robertson, G. P. Initial cultivation of a temperate-region soil immediately accelerates aggregate turnover and CO2 and N2O fluxes. Glob Chang Biol 12, 1507–1520 (2006).

  58.       Grandy, A. S. & Robertson, G. P. Aggregation and Organic Matter Protection Following Tillage of a Previously Uncultivated Soil. Soil Science Society of America Journal 70, 1398–1406 (2006).

  59.       Grasset, L., Rovira, P. & Amblès, A. TMAH-preparative thermochemolysis for the characterization of organic matter in densimetric fractions of a Mediterranean forest soil. J Anal Appl Pyrolysis 85, 435–441 (2009).

  60.       Grünewald, G., Kaiser, K., Jahn, R. & Guggenberger, G. Organic matter stabilization in young calcareous soils as revealed by density fractionation and analysis of lignin-derived constituents. Org Geochem 37, 1573–1589 (2006).

  61.       Guan, S. et al. Soil organic carbon associated with aggregate-size and density fractions in a Mollisol amended with charred and uncharred maize straw. J Integr Agric 18, 1496–1507 (2019).

  62.       Guggenberger, G. & Zech, W. Soil organic matter composition under primary forest, pasture, and secondary forest succession, Region Huetar Norte, Costa Rica. For Ecol Manage 124, 93–104 (1999).

  63.       Han, X. et al. Understanding soil carbon sequestration following the afforestation of former arable land by physical fractionation. Catena (Amst) 150, 317–327 (2017).

  64.       Hao, X. et al. Redistribution of Different Organic Carbon Fractions in the Soil Profile of a Typical Chinese Mollisol with Land-Use Change. Commun Soil Sci Plant Anal 48, 2369–2380 (2017).

  65.       Hassink, J. Density fractions of soil macroorganic matter and microbial biomass as predictors of C and N mineralization. Soil Biol Biochem 27, 1099–1108 (1995).

  66.       Hatton, P. J. et al. Transfer of litter-derived N to soil mineral-organic associations: Evidence from decadal 15N tracer experiments. Org Geochem 42, 1489–1501 (2012).

  67.       Hatton, P. J. et al. Assimilation and accumulation of C by fungi and bacteria attached to soil density fractions. Soil Biol Biochem 79, 132–139 (2014).

  68.       Herrmann, A. M. & Witter, E. Predictors of gross N mineralization and immobilization during decomposition of stabilized organic matter in agricultural soil. Eur J Soil Sci 59, 653–664 (2008).

  69.       Hicks Pries, C. E., Bird, J. A., Castanha, C., Hatton, P. J. & Torn, M. S. Long term decomposition: the influence of litter type and soil horizon on retention of plant carbon and nitrogen in soils. Biogeochemistry 134, 5–16 (2017).

  70.       Haung, Q.-R. et al. Effects of Long-Term Fertilization on Soil Organic Carbon and Nitrogen in a Highland Agroecosystem. Pedosphere 27, 727–734 (2009).

  71.       Huang, S., Peng, X., Huang, Q. & Zhang, W. Soil aggregation and organic carbon fractions affected by long-term fertilization in a red soil of subtropical China. Geoderma 154, 364–369 (2010).

  72.       Huang, S., Rui, W., Peng, X., Huang, Q. & Zhang, W. Organic carbon fractions affected by long-term fertilization in a subtropical paddy soil. Nutr Cycl Agroecosyst 86, 153–160 (2010).

  73.       Huang, S., Sun, Y. N., Rui, W. Y., Liu, W. R. & Zhang, W. J. Long-Term Effect of No-Tillage on Soil Organic Carbon Fractions in a Continuous Maize Cropping System of Northeast China. Pedosphere 20, 285–292 (2010).

  74.       Hunziker, M., Caviezel, C. & Kuhn, N. J. Shrub encroachment by green alder on subalpine pastures: Changes in mineral soil organic carbon characteristics. Catena (Amst) 157, 35–46 (2017).

  75.       Hunziker, M., Arnalds, O. & Kuhn, N. J. Evaluating the carbon sequestration potential of volcanic soils in southern Iceland after birch afforestation. Soil 5, 223–238 (2019).

  76.       Jiang, H., Han, X., Zou, W., Hao, X. & Zhang, B. Seasonal and long-term changes in soil physical properties and organic carbon fractions as affected by manure application rates in the Mollisol region of Northeast China. Agric Ecosyst Environ 268, 133–143 (2018).

  77.       Jing, Y. et al. Interactive effects of soil warming, throughfall reduction, and root exclusion on soil microbial community and residues in warm-temperate oak forests. Applied Soil Ecology 142, 52–58 (2019).

  78.       John, B., Yamashita, T., Ludwig, B. & Flessa, H. Storage of organic carbon in aggregate and density fractions of silty soils under different types of land use. Geoderma 128, 63–79 (2005).

  79.       Johnsen, K. H., Samuelson, L. J., Sanchez, F. G. & Eaton, R. J. Soil carbon and nitrogen content and stabilization in mid-rotation, intensively managed sweetgum and loblolly pine stands. For Ecol Manage 302, 144–153 (2013).

  80.       Jones, E. & Singh, B. Organo-mineral interactions in contrasting soils under natural vegetation. Front Environ Sci 2, 1–15 (2014).

  81.       Kader, M. A., Sleutel, S., D’Haene, K. & De Neve, S. Limited influence of tillage management on organic matter fractions in the surface layer of silt soils under cerealroot crop rotations. Australian Journal of Soil Research 48, 16–26 (2010).

  82.       Kalinina, O. et al. Self-restoration of post-agrogenic chernozems of Russia: Soil development, carbon stocks, and dynamics of carbon pools. Geoderma 162, 196–206 (2011).

  83.       Kalinina, O. et al. Self-restoration of post-agrogenic Albeluvisols: Soil development, carbon stocks and dynamics of carbon pools. Geoderma 207–208, 221–233 (2013).

  84.       Kalinina, O. et al. Self-restoration of post-agrogenic soils of Calcisol-Solonetz complex: Soil development, carbon stock dynamics of carbon pools. Geoderma 237, 117–128 (2015).

  85.       Kalinina, O. et al. Post-agricultural restoration: Implications for dynamics of soil organic matter pools. Catena (Amst) 181, 104096 (2019).

  86.       Karbozova-Saljnikov, E., Funakawa, S., Akhmetov, K. & Kosaki, T. Soil organic matter status of Chernozem soil in North Kazakhstan: Effects of summer fallow. Soil Biol Biochem 36, 1373–1381 (2004).

  87.       Kim, S. Y., Pramanik, P., Gutierrez, J., Hwang, H. Y. & Kim, P. J. Comparison of methane emission characteristics in air-dried and composted cattle manure amended paddy soil during rice cultivation. Agric Ecosyst Environ 197, 60–67 (2014).

  88.       Knowles, M. E., Ross, D. S. & Görres, J. H. Effect of the endogeic earthworm Aporrectodea tuberculata on aggregation and carbon redistribution in uninvaded forest soil columns. Soil Biol Biochem 100, 192–200 (2016).

  89.       Koarashi, J., Nishimura, S., Atarashi-Andoh, M., Muto, K. & Matsunaga, T. A new perspective on the 137 Cs retention mechanism in surface soils during the early stage after the Fukushima nuclear accident. Sci Rep 9, 1–10 (2019).

  90.       Kögel-Knabner, I. & Ziegler, F. Carbon distribution in different compartments of forest soils. Geoderma 56, 515–525 (1993).

  91.       Kogut, B. M., Artemyeva, Z. S., Kirillova, N. P., Yashin, M. A. & Soshnikova, E. I. Organic Matter of the Air-Dry and Water-Stable Macroaggregates (2–1 mm) of Haplic Chernozem in Contrasting Variants of Land Use. Eurasian Soil Science 52, 141–149 (2019).

  92.       Kölbl, A. et al. Grazing changes topography-controlled topsoil properties and their interaction on different spatial scales in a semi-arid grassland of Inner Mongolia, P.R. China. Plant Soil 340, 35–58 (2011).

  93.       Kölbl, A., Marschner, P., Fitzpatrick, R., Mosley, L. & Kögel-Knabner, I. Linking organic matter composition in acid sulfate soils to pH recovery after re-submerging. Geoderma 308, 350–362 (2017).

  94.       Kondo, M., Uchida, M. & Shibata, Y. Radiocarbon-based residence time estimates of soil organic carbon in a temperate forest: Case study for the density fractionation for Japanese volcanic ash soil. Nucl Instrum Methods Phys Res B 268, 1073–1076 (2010).

  95.       Kooch, Y. & Bayranvand, M. Labile soil organic matter changes related to forest floor quality of tree species mixtures in Oriental beech forests. Ecol Indic 107, 105598 (2019).

  96.       Kreyling, O. et al. Density fractionation of organic matter in dolomite-derived soils. Journal of Plant Nutrition and Soil Science 176, 509–519 (2013).

  97.       Kumar, S. et al. Long-term tillage and drainage influences on soil organic carbon dynamics, aggregate stability and corn yield. Soil Sci Plant Nutr 60, 108–118 (2014).

  98.       Kumari, M. et al. Soil Aggregation and Associated Organic Carbon Fractions as Affected by Tillage in a Rice–Wheat Rotation in North India. Soil Science Society of America Journal 75, 560–567 (2011).

  99.       Lajtha, K. et al. Changes to particulate versus mineral-associated soil carbon after 50 years of litter manipulation in forest and prairie experimental ecosystems. Biogeochemistry 119, 341–360 (2014).

  100.     Lehtinen, T. et al. Aggregation and organic matter in subarctic Andosols under different grassland management. Acta Agric Scand B Soil Plant Sci 65, 246–263 (2015).

  101.     Li, Y., Ruan, H., Zou, X. & Myster, R. W. Response of major soil decomposers to landslide disturbance in a Puerto Rican rainforest. Soil Sci 170, 202–211 (2005).

  102.     Li, Y., Xu, M., Zou, X., Shi, P. & Zhang, Y. Comparing soil organic carbon dynamics in plantation and secondary forest in wet tropics in Puerto Rico. Glob Chang Biol 11, 239–248 (2005).

  103.     Li, Y., Xu, M. & Zou, X. Effects of nutrient additions on ecosystem carbon cycle in a Puerto Rican tropical wet forest. Glob Chang Biol 12, 284–293 (2006).

  104.     Li, H., Han, X., Wang, F., Qiao, Y. & Xing, B. Impact of soil management on organic carbon content and aggregate stability. Commun Soil Sci Plant Anal 38, 1673–1690 (2007).

  105.     Li, H., Han, X., You, M. & Xing, B. Organic Matter Associated with Soil Aggregate Fractions of a Black Soil in Northeast China: Impacts of Land-Use Change and Long-Term Fertilization. Commun Soil Sci Plant Anal 46, 405–423 (2015).

  106.     Li, X., Vogeler, I. & Schwendenmann, L. Soil aggregation and soil fraction associated carbon under different vegetation types in a complex landscape. Soil Research 57, 215–227 (2019).

  107.     Li, J. et al. Response of soil organic carbon fractions, microbial community composition and carbon mineralization to high-input fertilizer practices under an intensive agricultural system. PLoS One 13, 1–16 (2018).

  108.     Li, T. et al. Soil erosion affects variations of soil organic carbon and soil respiration along a slope in Northeast China. Ecol Process 8, (2019).

  109.     Liao, J. D., Boutton, T. W. & Jastrow, J. D. Organic matter turnover in soil physical fractions following woody plant invasion of grassland: Evidence from natural 13C and 15N. Soil Biol Biochem 38, 3197–3210 (2006).

  110.     Liaudanskiene, I., Slepetiene, A., Velykis, A. & Satkus, A. Orgaanilise süsiniku paiknemine huumuse ja granulodensimeetrilistes fraktsioonides sõltuvalt mullaharimisest ning külvikorrast. Estonian Journal of Ecology 62, 53–69 (2013).

  111.     Lichter, J. et al. Soil carbon sequestration in a pine forest after 9 years of atmospheric CO2 enrichment. Ecology 86, 1835–1847 (2005).

  112.     Lin, Y., Slessarev, E. W., Yehl, S. T., D’Antonio, C. M. & King, J. Y. Long-term Nutrient Fertilization Increased Soil Carbon Storage in California Grasslands. Ecosystems 22, 754–766 (2019).

  113.     Llorente, M., Glaser, B. & Turrión, M. B. Storage of organic carbon and Black carbon in density fractions of calcareous soils under different land uses. Geoderma 159, 31–38 (2010).

  114.     Llorente, M., Glaser, B. & Turrión, M. B. Effect of land use change on contents and distribution of monosacharides within density fractions of calcareous soil. Soil Biol Biochem 107, 260–268 (2017).

  115.     Luan, J. et al. Assessments of the impacts of Chinese fir plantation and natural regenerated forest on soil organic matter quality at Longmen mountain, Sichuan, China. Geoderma 156, 228–236 (2010).

  116.     Luan, J., Liu, S., Wang, J., Zhu, X. & Shi, Z. Rhizospheric and heterotrophic respiration of a warm-temperate oak chronosequence in China. Soil Biol Biochem 43, 503–512 (2011).

  117.     Luan, J., Liu, S., Zhu, X., Wang, J. & Liu, K. Roles of biotic and abiotic variables in determining spatial variation of soil respiration in secondary oak and planted pine forests. Soil Biol Biochem 44, 143–150 (2012).

  118.     Luan, J. et al. Soil carbon stocks and quality across intact and degraded alpine wetlands in Zoige, east Qinghai-Tibet Plateau. Wetl Ecol Manag 22, 427–438 (2014).

  119.     Lyu, M. et al. Land use change exerts a strong impact on deep soil C stabilization in subtropical forests. J Soils Sediments 17, 2305–2317 (2017).

  120.     Ma, L., Guo, C., Xin, X., Yuan, S. & Wang, R. Effects of belowground litter addition, increased precipitation and clipping on soil carbon and nitrogen mineralization in a temperate steppe. Biogeosciences 10, 7361–7372 (2013).

  121.     Maiga, A. et al. Responses of soil organic carbon, aggregate stability, carbon and nitrogen fractions to 15 and 24 years of no-till diversified crop rotations. Soil Research 57, 149–157 (2019).

  122.     Malhi, S. S., Légère, A., Vanasse, A. & Parent, G. Effects of long-term tillage, terminating no-till and cropping system on organic C and N, and available nutrients in a Gleysolic soil in Québec, Canada. Journal of Agricultural Science 156, 472–480 (2018).

  123.     Mastrolonardo, G., Certini, G., Krebs, R., Forte, C. & Egli, M. Effects of fire on soil organic matter quality along an altitudinal sequence on Mt. Etna, Sicily. Catena (Amst) 110, 133–145 (2013).

  124.     Miller, G. A., Rees, R. M., Griffiths, B. S., Ball, B. C. & Cloy, J. M. The sensitivity of soil organic carbon pools to land management varies depending on former tillage practices. Soil Tillage Res 194, 104299 (2019).

  125.     Mujuru, L., Gotora, T., Velthorst, E. J., Nyamangara, J. & Hoosbeek, M. R. Soil carbon and nitrogen sequestration over an age sequence of Pinus patula plantations in Zimbabwean Eastern Highlands. For Ecol Manage 313, 254–265 (2014).

  126.     Oorts, K., Bossuyt, H., Labreuche, J., Merckx, R. & Nicolardot, B. Carbon and nitrogen stocks in relation to organic matter fractions, aggregation and pore size distribution in no-tillage and conventional tillage in northern France. Eur J Soil Sci 58, 248–259 (2007).

  127.     Parker, J. L., Fernandez, I. J., Rustad, L. E. & Norton, S. A. Soil organic matter fractions in experimental forested watersheds. Water Air Soil Pollut 138, 101–121 (2002).

  128.     Phillips, C. L., Murphey, V., Lajtha, K. & Gregg, J. W. Asymmetric and symmetric warming increases turnover of litter and unprotected soil C in grassland mesocosms. Biogeochemistry 128, 217–231 (2016).

  129.     Plaza, C. et al. Response of different soil organic matter pools to biochar and organic fertilizers. Agric Ecosyst Environ 225, 150–159 (2016).

  130.     Poffenbarger, H. J. et al. Legacy effects of long-term nitrogen fertilizer application on the fate of nitrogen fertilizer inputs in continuous maize. Agric Ecosyst Environ 265, 544–555 (2018).

  131.     Prado, M. R. V., Ramos, F. T., Weber, O. L. dos S. & Müller, C. B. Organic Carbon and Total Nitrogen in the Densimetric Fractions of Organic Matter Under Different Soil Management. Revista Caatinga 29, 263–273 (2016).

  132.     Puissant, J. et al. Climate change effects on the stability and chemistry of soil organic carbon pools in a subalpine grassland. Biogeochemistry 132, 123–139 (2017).

  133.     Rasmussen, C., Torn, M. S. & Southard, R. J. Mineral Assemblage and Aggregates Control Carbon Dynamics in a California Conifer Forest. Soil Science Society of America Journal 69, 1711–1721 (2005).

  134.     Richards, A. E., Dalal, R. C. & Schmidt, S. Soil carbon turnover and sequestration in native subtropical tree plantations. Soil Biol Biochem 39, 2078–2090 (2007).

  135.     Rovira, P. & Vallejo, V. R. Physical protection and biochemical quality of organic matter in mediterranean calcareous forest soils: A density fractionation approach. Soil Biol Biochem 35, 245–261 (2003).

  136.     Schellekens, J. et al. Molecular composition of several soil organic matter fractions from anthropogenic black soils (Terra Preta de Índio) in Amazonia — A pyrolysis-GC/MS study. Geoderma 288, 154–165 (2017).

  137.     Schiedung, M. et al. Thermal oxidation does not fractionate soil organic carbon with differing biological stabilities. Journal of Plant Nutrition and Soil Science 180, 18–26 (2017).

  138.     Schrumpf, M. et al. Storage and stability of organic carbon in soil profiles Storage and stability of organic carbon in soils as related to depth, occlusion within aggregates, and attachment to minerals Storage and stability of organic carbon in soil profiles. Biogeosciences Discussions 9, 13085–13133 (2012).

  139.     Schwendenmann, L. & Pendall, E. Effects of forest conversion into grassland on soil aggregate structure and carbon storage in Panama: Evidence from soil carbon fractionation and stable isotopes. Plant Soil 288, 217–232 (2006).

  140.     Shen, D. et al. Increased chemical stability but decreased physical protection of soil organic carbon in response to nutrient amendment in a Tibetan alpine meadow. Soil Biol Biochem 126, 11–21 (2018).

  141.     Shi, X. M. et al. Dynamics of soil organic carbon and nitrogen associated with physically separated fractions in a grassland-cultivation sequence in the Qinghai-Tibetan plateau. Biol Fertil Soils 46, 103–111 (2010).

  142.     Shi, X. M. et al. Grazing exclusion decreases soil organic C storage at an alpine grassland of the Qinghai-Tibetan Plateau. Ecol Eng 57, 183–187 (2013).

  143.     Six, J., Elliott, E. T. & Paustian, K. Aggregate and Soil Organic Matter Dynamics under Conventional and No‐Tillage Systems. Soil Science Society of America Journal 63, 1350–1358 (1999).

  144.     Six, J., Paustian, K., Elliott, E. T. & Combrink, C. Soil Structure and Organic Matter I. Distribution of Aggregate‐Size Classes and Aggregate‐Associated Carbon. Soil Science Society of America Journal 64, 681–689 (2000).

  145.     Sleutel, S., De Neve, S., Németh, T., Tóth, T. & Hofman, G. Effect of manure and fertilizer application on the distribution of organic carbon in different soil fractions in long-term field experiments. European Journal of Agronomy 25, 280–288 (2006).

  146.     Sleutel, S., De Neve, S., Singier, B. & Hofman, G. Organic C levels in intensively managed arable soils - Long-term regional trends and characterization of fractions. Soil Use Manag 22, 188–196 (2006).

  147.     Sollins, P., Spycher, G. & Topik, C. Processes of Soil Organic-Matter Accretion at a Mudflow Chronosequence, Mt. Shasta, California. Ecology 64, 1273–1282 (1983).

  148.     Sollins, P., Spycher, G. & Glassman, C. A. Net nitrogen mineralization from light- and heavy-fraction forest soil organic matter. Soil Biol Biochem 16, 31–37 (1984).

  149.     Sollins, P. et al. Sequential density fractionation across soils of contrasting mineralogy: Evidence for both microbial- and mineral-controlled soil organic matter stabilization. Biogeochemistry 96, 209–231 (2009).

  150.     Sootahar, M. K. et al. The effect of fulvic acids derived from different materials on changing properties of albic black soil in the Northeast Plain of China. Molecules 24, 1–12 (2019).

  151.     Stahr, S. et al. Phosphorus speciation and C:N:P stoichiometry of functional organic matter fractions in temperate forest soils. Plant Soil 427, 53–69 (2018).

  152.     Steffens, M., Kölbl, A., Schörk, E., Gschrey, B. & Kögel-Knabner, I. Distribution of soil organic matter between fractions and aggregate size classes in grazed semiarid steppe soil profiles. Plant Soil 338, 63–81 (2011).

  153.     Strickland, T. C. & Sollins, P. Improved Method for Separating Light and Heavy-Fraction Organic Material from Soil. Soil Science Society of America Journal 51, 1390–1393 (1987).

  154.     Struecker, J., Kaiser, M., Dyckmans, J. & Joergensen, R. G. Maize root decomposition in subsoil horizons of two silt loams differing in soil organic C accumulation due to colluvial processes. Geoderma 283, 101–109 (2016).

  155.     Stutz, K. P., Dann, D., Wambsganss, J., Scherer-Lorenzen, M. & Lang, F. Phenolic matter from deadwood can impact forest soil properties. Geoderma 288, 204–212 (2017).

  156.     Swanston, C. W., Caldwell, B. A., Homann, P. S., Ganio, L. & Sollins, P. Carbon dynamics during a long-term incubation of separate and recombined density fractions from seven forest soils. Soil Biol Biochem 34, 1121–1130 (2002).

  157.     Swanston, C. W. et al. Initial characterization of processes of soil carbon stabilization using forest stand-level radiocarbon enrichment. Geoderma 128, 52–62 (2005).

  158.     Throop, H. L., Lajtha, K. & Kramer, M. Density fractionation and 13C reveal changes in soil carbon following woody encroachment in a desert ecosystem. Biogeochemistry 112, 409–422 (2013).

  159.     Tian, J. et al. Response of soil organic matter fractions and composition of microbial community to long-term organic and mineral fertilization. Biol Fertil Soils 53, 523–532 (2017).

  160.     Tong, X. et al. Long-term fertilization effects on organic carbon fractions in a red soil of China. Catena (Amst) 113, 251–259 (2014).

  161.     Tong, X. et al. Change in Carbon Storage in Soil Physical Fractions after Afforestation of Former Arable Land. Soil Science Society of America Journal 80, 1098–1106 (2016).

  162.     Valdez, Z. P., Hockaday, W. C., Masiello, C. A., Gallagher, M. E. & Philip Robertson, G. Soil Carbon and Nitrogen Responses to Nitrogen Fertilizer and Harvesting Rates in Switchgrass Cropping Systems. Bioenergy Res 10, 456–464 (2017).

  163.     Van Groenigen, K. J., Harris, D., Horwath, W. R., Hartwig, U. A. & Van Kessel, C. Linking sequestration of 13C and 15N in aggregates in a pasture soil following 8 years of elevated atmospheric CO2. Glob Chang Biol 8, 1094–1108 (2002).

  164.     Van Leeuwen, J. P. et al. An ecosystem approach to assess soil quality in organically and conventionally managed farms in Iceland and Austria. Soil 1, 83–101 (2015).

  165.     Veres, Z. et al. Soil extracellular enzyme activities are sensitive indicators of detrital inputs and carbon availability. Applied Soil Ecology 92, 18–23 (2015).

  166.     Vieira, F. C. B. et al. Carbon management index based on physical fractionation of soil organic matter in an Acrisol under long-term no-till cropping systems. Soil Tillage Res 96, 195–204 (2007).

  167.     von Haden, A. C., Kucharik, C. J., Jackson, R. D. & Marín-Spiotta, E. Litter quantity, litter chemistry, and soil texture control changes in soil organic carbon fractions under bioenergy cropping systems of the North Central U.S. Biogeochemistry 143, 313–326 (2019).

  168.     Wagai, R., Mayer, L. M., Kitayama, K. & Knicker, H. Climate and parent material controls on organic matter storage in surface soils: A three-pool, density-separation approach. Geoderma 147, 23–33 (2008).

  169.     Wagai, R., Kajiura, M., Asano, M. & Hiradate, S. Nature of soil organo-mineral assemblage examined by sequential density fractionation with and without sonication: Is allophanic soil different? Geoderma 241–242, 295–305 (2015).

  170.     Wagai, R., Kajiura, M., Uchida, M. & Asano, M. Distinctive roles of two aggregate binding agents in allophanic andisols: Young carbon and poorly-crystalline metal phases with old carbon. Soil Syst 2, 1–23 (2018).

  171.     Wander, M. M. & Bidart, M. G. Tillage practice influences on the physical protection, bioavailability and composition of particulate organic matter. Biol Fertil Soils 32, 360–367 (2000).

  172.     Wander, M. M. & Yang, X. Influence of tillage on the dynamics of loose- and occluded-particulate and humified organic matter fractions. Soil Biol Biochem 32, 1151–1160 (2000).

  173.     Wang, F. et al. Tropical forest restoration: Fast resilience of plant biomass contrasts with slow recovery of stable soil C stocks. Funct Ecol 31, 2344–2355 (2017).

  174.     Wang, J. J. et al. Long-term nitrogen addition suppresses microbial degradation, enhances soil carbon storage, and alters the molecular composition of soil organic matter. Biogeochemistry 142, 299–313 (2019).

  175.     Wick, A. F., Ingram, L. J. & Stahl, P. D. Aggregate and organic matter dynamics in reclaimed soils as indicated by stable carbon isotopes. Soil Biol Biochem 41, 201–209 (2009).

  176.     Wick, A. F., Stahl, P. D. & Ingram, L. J. Aggregate‐Associated Carbon and Nitrogen in Reclaimed Sandy Loam Soils. Soil Science Society of America Journal 73, 1852–1860 (2009).

  177.     Wick, A. F., Stahl, P. D., Ingram, L. J. & Vicklund, L. Soil aggregation and organic carbon in short-term stockpiles. Soil Use Manag 25, 311–319 (2009).

  178.     Wick, A. F., Phillips, R. L., Liebig, M. A., West, M. & Daniels, W. L. Linkages between soil micro-site properties and CO 2 and N 2O emissions during a simulated thaw for a northern prairie Mollisol. Soil Biol Biochem 50, 118–125 (2012).

  179.     Wick, A. F., Daniels, W. L., Orndorff, Z. W. & Alley, M. M. Organic matter accumulation post-mineral sands mining. Soil Use Manag 29, 354–364 (2013).

  180.     Wiesmeier, M. et al. Aggregate stability and physical protection of soil organic carbon in semi-arid steppe soils. Eur J Soil Sci 63, 22–31 (2012).

  181.     Wiesmeier, M. et al. Carbon storage capacity of semi-arid grassland soils and sequestration potentials in northern China. Glob Chang Biol 21, 3836–3845 (2015).

  182.     Xiao, C. W. et al. Belowground carbon pools and dynamics in China’s warm temperate and sub-tropical deciduous forests. Biogeosciences 7, 275–287 (2010).

  183.     Xu, Y. et al. Effects of irrigation management during the rice growing season on soil organic carbon pools. Plant Soil 421, 337–351 (2017).

  184.     Xu, S. et al. Conversion of native rangelands into cultivated pasturelands in subtropical ecosystems: Impacts on aggregate-associated carbon and nitrogen. J Soil Water Conserv 73, 156–163 (2018).

  185.     Yamashita, T., Flessa, H., John, B., Helfrich, M. & Ludwig, B. Organic matter in density fractions of water-stable aggregates in silty soils: Effect of land use. Soil Biol Biochem 38, 3222–3234 (2006).

  186.     Yang, C., Ni, H., Zhong, Z., Zhang, X. & Bian, F. Changes in soil carbon pools and components induced by replacing secondary evergreen broadleaf forest with Moso bamboo plantations in subtropical China. Catena (Amst) 180, 309–319 (2019).

  187.     Yao, S. H. et al. Labile and recalcitrant components of organic matter of a Mollisol changed with land use and plant litter management: An advanced 13 C NMR study. Science of the Total Environment 660, 1–10 (2019).

  188.     Yeasmin, S., Singh, B., Johnston, C. T. & Sparks, D. L. Evaluation of pre-treatment procedures for improved interpretation of mid infrared spectra of soil organic matter. Geoderma 304, 83–92 (2017).

  189.     Zhang, J., Wang, S., Feng, Z. & Wang, Q. Stability of soil organic carbon changes in successive rotations of Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) plantations. Journal of Environmental Sciences 21, 352–359 (2009).

  190.     Zhang, B. & Peng, X.-H. Organic Matter Enrichment and Aggregate Stabilization in a Severely Degraded Ultisol After Reforestation. Pedosphere 16, 699–706 (2006).

  191.     Zhao, H. et al. Effect of straw amendment modes on soil organic carbon, nitrogen sequestration and crop yield on the North-Central Plain of China. Soil Use Manag 35, 511–525 (2019).

  192.     Zhe E, S. et al. Long-term fertilization and manuring effects on physically separated soil organic-matter pools under continuous wheat cropping at a rainfed semiarid site in China. Journal of Plant Nutrition and Soil Science 175, 689–697 (2012).

  193.     Zhong, Y., Yan, W. & Shangguan, Z. Soil carbon and nitrogen fractions in the soil profile and their response to long-term nitrogen fertilization in a wheat field. Catena (Amst) 135, 38–46 (2015).

  194.     Zotarelli, L., Alves, B. J. R., Urquiaga, S., Boddey, R. M. & Six, J. Impact of tillage and crop rotation on light fraction and intra-aggregate soil organic matter in two Oxisols. Soil Tillage Res 95, 196–206 (2007).

  195.     Guidi, C., Magid, J., Rodeghiero, M., Gianelle, D. & Vesterdal, L. Effects of forest expansion on mountain grassland: changes within soil organic carbon fractions. Plant Soil 385, 373–387 (2014).

  196.     Li, S. et al. Distribution and storage of crop residue carbon in aggregates and its contribution to organic carbon of soil with low fertility. Soil Tillage Res 155, 199–206 (2016).

  197.     Parfitt, R. L., Theng, B. K. G., Whitton, J. S. & Shepherd, T. G. Effects of clay minerals and land use on organic matter pools. Geoderma 75, 1–12 (1997).

  198.     Cui, J. et al. Physical and chemical stabilization of soil organic carbon along a 500-year cultived soil chronosequence originating from estuarine wetlands: Temporal patterns and land use effects. Agric Ecosyst Environ 196, 10–20 (2014).