https://ogma.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:42884 Wed 28 Feb 2024 15:20:48 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:47725 2 emission into the atmosphere along with the soil respiratory CO₂ fluxes but is comparatively less studied than the organic C mineralisation processes. This study aims to understand how soil available carbonates influence the soil C dynamics under different tillage, mulching and temperature regimes. A 90-day incubation experiment was conducted by adding calcite nodules to soils (10% w/w) collected from an agricultural field maintained with or without 5 t ha⁻¹ mulching under no-till (NT) or conventional tillage (CT) systems. Environmental Scanning Electron Microscope (ESEM) examination indicated greater morphological changes in the calcite nodules incubated with CT than NT soils. Soil samples incubated with calcite and mulching recorded 6.3% greater CO₂ evolution than the un-mulched condition. Under the CT system, the overall CO₂ emission rate was higher in the control treatment (43%), followed by a combined treatment of 5 t ha⁻¹ mulch + CaCO₃ (10% w/w) (29.2%), 5 t ha⁻¹ mulch only treatment (27.9%), and 10% CaCO₃ (w/w) (16.5%) treatment, with a rise in incubation temperature from 22 °C to 37 °C. Kinetic model calculations for CO₂ emission indicated a greater half-life of easily mineralisable C pools in the NT system at 22 °C. Microbial biomass carbon (MBC) results further verified that the high temperature and disturbed soil conditions limit the availability of soil MBC under the CT systems, indicating a higher decomposition rate. Eventually, these results indicated that agricultural management practices, including tillage shift, explicitly influence the different functional components of soil organic matter (SOM).]]> Wed 28 Feb 2024 14:56:49 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:38226 75 μm), was 13.4% higher under CT, but mesoporosity (30–75 μm) was 9.6% higher under NT. The vertical distributions of root biomass and root architecture measurements (i.e. root length density) in undisturbed soil cores were 9.6% higher under the NT and 8.7% higher under the CT system respectively. These results suggest that low soil disturbance under the continuous NT system may have encouraged accumulation of more root biomass in the top 100 mm depth, thus developing better soil structure. Overall, µXCT image analyses of soil cores indicated that this tillage shift affected the soil total carbon, due to the significantly higher soil-pore (i.e. pore surface area, porosity and average pore size area) and root architecture (i.e. root length density, root surface density and root biomass) measurements under the CT system.]]> Mon 16 Aug 2021 15:47:54 AEST ]]>