title: Interactive priming of biochar and labile organic matter mineralization in a smectite-rich soil.
abstract: Biochar is considered as an attractive tool for long-term carbon (C) storage in soil. However, there is limited knowledge about the effect of labile organic matter (LOM) on biochar-C mineralization in soil or the vice versa. An incubation experiment (20 °C) was conducted for 120 days to quantify the interactive priming effects of biochar-C and LOM-C mineralization in a smectitic clayey soil. Sugar cane residue (source of LOM) at a rate of 0, 1, 2, and 4% (w/w) in combination with two wood biochars (450 and 550 °C) at a rate of 2% (w/w) were applied to the soil. The use of biochars (~ -36‰) and LOM (-12.7‰) or soil (-14.3‰) with isotopically distinct δ(13)C values allowed the quantification of C mineralized from biochar and LOM/soil. A small fraction (0.4-1.1%) of the applied biochar-C was mineralized, and the mineralization of biochar-C increased significantly with increasing application rates of LOM, especially during the early stages of incubation. Concurrently, biochar application reduced the mineralization of LOM-C, and the magnitude of this effect increased with increasing rate of LOM addition. Over time, the interactive priming of biochar-C and LOM-C mineralization was stabilized. Biochar application possesses a considerable merit for long-term soil C-sequestration, and it has a stabilizing effect on LOM in soil.
authors.affiliation: Faculty of Agriculture, Food, and Natural Resources, The University of Sydney, NSW 2006, Australia.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Keith
authors.forename: Balwant
authors.initials: B
authors.lastname: Singh
authors.forename: Bhupinder Pal
authors.initials: BP
authors.lastname: Singh
mesh_terms: D002606:Charcoal / Q000737:chemistry*; D017640:Silicates / Q000737:chemistry*; D012987:Soil / Q000737:chemistry*; D013696:Temperature
chemical_list: D017640:Silicates; D012987:Soil; C540010:biochar; D002606:Charcoal; C033214:Smectite