https://ogma.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:45684 Wed 07 Feb 2024 16:37:32 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:34657 Tue 03 Sep 2019 18:27:15 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:29473 Thu 21 Oct 2021 12:52:02 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:30741 13CO₂ pulse labelling of ryegrass was used to monitor belowground C allocation, SOC priming, and stabilization of root-derived C for a 15-month period—commencing 8.2 years after biochar (Eucalyptus saligna, 550 °C) was amended into a subtropical ferralsol. We found that field-aged biochar enhanced the belowground recovery of new root-derived C (¹³C) by 20%, and facilitated negative rhizosphere priming (it slowed SOC mineralization by 5.5%, that is, 46 g CO₂-C m⁻² yr⁻¹). Retention of root-derived ¹³C in the stable organo-mineral fraction (<53 μm) was also increased (6%, P < 0.05). Through synchrotron-based spectroscopic analysis of bulk soil, field-aged biochar and microaggregates (<250 μm), we demonstrate that biochar accelerates the formation of microaggregates via organo-mineral interactions, resulting in the stabilization and accumulation of SOC in a rhodic ferralsol.]]> Sat 24 Mar 2018 07:39:28 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:44905 Mon 24 Oct 2022 16:10:33 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:47969 Mon 13 Feb 2023 15:58:55 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:34515 in situ during composting using Fourier Transform Infrared Spectroscopy (FTIR). Emissions of N₂O from the biochar-amended composting mixtures decreased significantly (P < 0.05) soon after commencement of the composting process compared with the non-amended control. The cumulative emissions of N₂O over 8 weeks in the GWB composting mixture (GWBC), PLB composting mixture (PLBC) and control (no biochar) were 4.2, 5.0 and 14.0 g N₂O-N kg⁻¹ of total nitrogen (TN) in composting mixture, respectively (P < 0.05). The CH₄ emissions were significantly (P < 0.05) lower in the GWBC and PLBC treatments than the control during the period from day 8 to day 36, when anaerobic conditions likely prevailed. The cumulative CH4 emissions were 12, 18 and 80 mg CH₄-C kg⁻¹ of total carbon (TC) for the GWBC, PLBC and control treatments, respectively, though due to wide variation between replicates this difference was not statistically significant. The cumulative N₂O and CH₄ emissions were similar between the GWBC and PLBC despite differences in properties of the two biochars. X-ray Photoelectron Spectroscopy (XPS) analysis and SEM imaging of the composted biochars indicated the presence of iron oxide compounds and amine-NH₃ on the surface and pores of the biochars (PLB > GWB). The change in nitrogen (N) functional groups on the biochar surface after composting is evidence for sorption and/or reaction with N from labile organic N, mineral N, and gaseous N (e.g. N₂O). The concentration of NH⁺₄ increased during the thermophilic phase and then decreased during the maturation phase, while NO⁻₃ accumulated during the maturation phase. Total N retained was significantly (P < 0.05) higher in the PLBC (740 g) and the GWBC (660 g) relative to the control (530 g). The TC retained was significantly higher in the GWBC (10.0 kg) and the PLBC (8.5 kg) cf. the control (6.0 kg). Total GHG emissions across the composting period were 50, 63 and 183 kg CO₂-eq t⁻¹ of initial mass of GWBC, PLBC and control (dry weight basis) respectively. These results support the co-composting of biochar to lower net emissions of GHGs while increasing N retention (and fertiliser N value) in the mature compost.]]> Fri 22 Mar 2019 12:57:03 AEDT ]]>