biostudies-literatureUnknown13(1)Weng ZHThe soil carbon (C) saturation concept suggests an upper limit to the storage of soil organic carbon (SOC). It is set by the mechanisms that protect soil organic matter from mineralization. Biochar has the capacity to protect new C, including rhizodeposits and microbial necromass. However, the decadal-scale mechanisms by which biochar influences the molecular diversity, spatial heterogeneity, and temporal changes in SOC persistence, remain unresolved. Here we show that the soil C storage ceiling of a Ferralsol under subtropical pasture was raised by a second application of Eucalyptus saligna biochar 8.2 years after the first application-the first application raised the soil C storage ceiling by 9.3 Mg new C ha^-1 and the second application raised this by another 2.3 Mg new C ha<sNature communications5177https://www.ebi.ac.uk/biostudies/studies/S-EPMC9440262biostudies-literatureMicrospectroscopic visualization of how biochar lifts the soil organic carbon ceiling.PMC9440262Cowie ATavakkoli EKlein ARFranks AEDiao HChang SLYVan Zwieten LKimber STang CJoseph SRose TJMorris SWeng ZHMacdonald LMRose MTSingh BPArchanjo BSSchweizer STobin MJVongsvivut JKopittke PMfalseMicrospectroscopic visualization of how biochar lifts the soil organic carbon ceiling.The soil carbon (C) saturation concept suggests an upper limit to the storage of soil organic carbon (SOC). It is set by the mechanisms that protect soil organic matter from mineralization. Biochar has the capacity to protect new C, including rhizodeposits and microbial necromass. However, the decadal-scale mechanisms by which biochar influences the molecular diversity, spatial heterogeneity, and temporal changes in SOC persistence, remain unresolved. Here we show that the soil C storage ceiling of a Ferralsol under subtropical pasture was raised by a second application of Eucalyptus saligna biochar 8.2 years after the first application-the first application raised the soil C storage ceiling by 9.3 Mg new C ha^-1 and the second application raised this by another 2.3 Mg new C ha<s2022-01-01T00:00:00Z2022 Sep2025-04-18T20:54:15.027Z2025-04-07T08:59:25.365ZS-EPMC94402623605602510.1038/s41467-022-32819-7