https://ogma.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:41068 2SO₄-H₂O₂ digested) was the dominant P fraction (37–51% of total P) in the aerobic soil under wheat, while it was decreased by 18–27% in flooded soil under rice cultivation. In contrast, the sparingly soluble Ca-bound P (HCl-Pi) increased from 25–31% under wheat cultivation to 41–50% under flooded rice (paddy) cultivation where reducing conditions are expected to prevail under submerged paddy soil conditions. The crop rotation not only altered the sparingly available P fraction but also influenced soil labile P, especially the organic P form. Compared with the rice soil, a 4-fold increase in the labile P fraction (NaHCO₃-Po) was observed in wheat soil. The moderately labile P fraction (NaOH-extractable) showed a similar trend to that of labile P pool, but the increased NaOH-Po in wheat soil was relatively small. The relatively rapid change in the residual P fraction was attributed to oxidation-reduction cycles of Fe oxides between flooded (rice) and aerobic (wheat) soil conditions. Conclusions: Wetting and drying cycles associated with a rice-wheat crop rotation promoted the transformation of the sparingly soluble soil P fraction between crops, which was attributed to changes in soil redox conditions, particularly Fe cycling. This indicated that the rice-wheat crop rotation can draw upon the sparingly soluble P fraction for crop production, thus relying less on fertilizer-applied P.]]> Wed 28 Feb 2024 14:57:36 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:32893 Wed 08 Aug 2018 10:05:32 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:49073 Wed 03 May 2023 16:07:56 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:29117 Oenothera picensis in a Cu-contaminated soil. Materials and methods: A Cu-contaminated sandy soil (338 mg Cu kg^-1) was spiked and equilibrated with additional Cu (0, 100, and 500 mg Cu kg−¹). The spiked soil was then amended with CMB (0, 5, and 10 % w/w) and incubated for 2 weeks. The metallophyte was grown on these treatments under greenhouse conditions for 3 months. Pore water solutions were collected from the plant pots every 30 days. After the harvest, soil and pore water pH, soil Cu fractions, pore water Cu concentration, soil microbial activity, plant biomass weight, and Cu concentration in plant parts were determined. Results and discussion The CMB increased the pH of soils and soil pore water, and probably also soil major nutrients. It reduced the exchangeable fraction of Cu but increased its organic matter and residual fractions. At the same time, it decreased the Cu concentration in the soil pore water. The CMB increased basal respiration and dehydrogenase activity. The CMB application produced up to three and seven times more root and shoot biomass, respectively. In addition, shoots accumulated lesser Cu than control but roots did more. Plants survived in soil that was spiked with 500 mg Cu kg^-1, only when CMB dose was 10 %. Conclusions: The CMB affected the Cu uptake in plant by altering the mobility, bioavailability, and spatial distribution of Cu in soils. The increase in available nutrients and decrease in Cu toxicity facilitated plant growth. The increased microbial activity probably also promoted the plant growth and reduced the Cu bioavailability. Therefore, CMB can be used to remediate Cu-contaminated soils.]]> Sat 24 Mar 2018 07:36:56 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:38758 Mon 24 Jan 2022 15:01:09 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:30026 neutral > alkaline soil. The EC50 values resulting in 50% decrease in worm weight over control for Pb in acidic, neutral and alkaline soils were 460, 3606 and 5753 mg/kg soil, respectively. Thus, the acidic soil recorded an EC50 well below the soil guideline value for Pb. Whereas, the LC50 values resulting in 50% mortality in worms over control were 1161, 4648 and 7851 mg/kg, respectively, for acidic, neutral and alkaline soils. The Pb concentrations in earthworms ranged from 0.2 to 740 mg/kg wet weight. Soils with low clay content and acidic to neutral pH values demonstrated an increased Pb toxicity in earthworms compared to the soils with alkaline pH. Conclusions: The worm weight loss is a more sensitive parameter than the mortality. This study emphasizes that the soil regulatory levels for Pb are not protective of worms in acidic soils. Therefore, care should be taken when using the current regulatory limits to assess and predict the safety of a contaminated site with acidic soils towards the ecological health.]]> Mon 23 Sep 2019 12:50:26 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:30980 Mon 23 Sep 2019 12:09:43 AEST ]]> 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:38743 Fri 21 Jan 2022 09:47:08 AEDT ]]>