| Autor: |
Wang Y; College of Land Science and Technology, Key Laboratory of Arable Land Conservation (North China), Ministry of Agriculture, China Agricultural University, Beijing100193, China., Joseph S; School of Materials Science and Engineering, University of New South Wales (NSW), Sydney2052, New South Wales, Australia., Wang X; College of Land Science and Technology, Key Laboratory of Arable Land Conservation (North China), Ministry of Agriculture, China Agricultural University, Beijing100193, China., Weng ZH; School of Agriculture and Food Sciences, The University of Queensland, St. Lucia4072, Queensland, Australia., Mitchell DRG; Electron Microscopy Centre, Innovation Campus, University of Wollongong, Squires Way, North Wollongong2517, New South Wales, Australia., Nancarrow M; Electron Microscopy Centre, Innovation Campus, University of Wollongong, Squires Way, North Wollongong2517, New South Wales, Australia., Taherymoosavi S; School of Materials Science and Engineering, University of New South Wales (NSW), Sydney2052, New South Wales, Australia., Munroe P; School of Materials Science and Engineering, University of New South Wales (NSW), Sydney2052, New South Wales, Australia., Li G; College of Land Science and Technology, Key Laboratory of Arable Land Conservation (North China), Ministry of Agriculture, China Agricultural University, Beijing100193, China., Lin Q; College of Land Science and Technology, Key Laboratory of Arable Land Conservation (North China), Ministry of Agriculture, China Agricultural University, Beijing100193, China., Chen Q; College of Resources and Environmental Science, Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, China Agricultural University, Beijing100193, China., Flury M; Department of Crop and Soil Sciences, Washington State University, Puyallup, Washington98374, United States.; Department of Crop and Soil Sciences, Washington State University, Pullman, Washington99164, United States., Cowie A; School of Environmental and Rural Science, University of New England, Armidale2351, New South Wales, Australia.; NSW Department of Primary Industries, Armidale2351, New South Wales, Australia., Husson O; Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD), MontpellierF-34398, France.; Unité Propre de Recherche Agroécologie et Intensification Durable des Cultures Annuelles (UPR AIDA), MontpellierF-34398, France.; AIDA, Université de Montpellier, CIRAD, MontpellierF-34398, France., Van Zwieten L; NSW Department of Primary Industries, Wollongbar Primary Industries Institute, Wollongbar2477, New South Wales, Australia., Kuzyakov Y; Department of Soil Science of Temperate Ecosystems, Department of Agricultural Soil Science, University of Göttingen, Göttingen37077, Germany.; Peoples Friendship University of Russia (RUDN University), Moscow117198, Russia., Lehmann J; Soil and Crop Science, School of Integrative Plant Science, Cornell University, Ithaca, New York14853, United States., Li B; College of Land Science and Technology, Key Laboratory of Arable Land Conservation (North China), Ministry of Agriculture, China Agricultural University, Beijing100193, China., Shang J; College of Land Science and Technology, Key Laboratory of Arable Land Conservation (North China), Ministry of Agriculture, China Agricultural University, Beijing100193, China. |
| Abstrakt: |
Biochar amendments add persistent organic carbon to soil and can stabilize rhizodeposits and existing soil organic carbon (SOC), but effects of biochar on subsoil carbon stocks have been overlooked. We quantified changes in soil inorganic carbon (SIC) and SOC to 2 m depth 10 years after biochar application to calcareous soil. The total soil carbon (i.e., existing SOC, SIC, and biochar-C) increased by 71, 182, and 210% for B30, B60, and B90, respectively. Biochar application at 30, 60, and 90 t ha -1 rates significantly increased SIC by 10, 38, and 68 t ha -1 , respectively, with accumulation mainly occurring in the subsoil (below 1 m). This huge increase of SIC (mainly CaCO 3 ) is ∼100 times larger than the inorganic carbon present in the added biochar (0.3, 0.6, or 0.9 t ha -1 ). The benzene polycarboxylic acid method showed that the biochar-amended soil contained more black carbon particles (6.8 times higher than control soil) in the depth of 1.4-1.6 m, which provided the direct quantitative evidence for biochar migration into subsoil after a decade. Spectral and energy spectrum analysis also showed an obvious biochar structure in the biochar-amended subsoil, accompanied by a Ca/Mg carbonate cluster, which provided further evidence for downward migration of biochar after a decade. To explain SIC accumulation in subsoil with biochar amendment, the interacting mechanisms are proposed: (1) biochar amendment significantly increases subsoil pH (0.3-0.5 units) 10 years after biochar application, thus forming a favorable pH environment in the subsoil to precipitate HCO 3 - ; and (2) the transported biochar in subsoil can act as nuclei to precipitate SIC. Biochar amendment enhanced SIC by up to 80%; thus, the effects on carbon stocks in subsoil must be understood to inform strategies for carbon dioxide removal through biochar application. Our study provided critical knowledge on the impact of biochar application to topsoil on carbon stocks in subsoil in the long term. |
