https://ogma.newcastle.edu.au/vital/access/ /manager/Index ${session.getAttribute("locale")} 5 https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:45995 P > S > C. While in the black soil, it suggested that there is increasing microbial demand for only N and S. In the warmer months (May to Sep.), the microbial nutrient demands in the two soils were opposite to the colder months. The results suggested differential changes in microbial nutrient limitation with warming, which has significant implications for the carbon stocks management in farmlands under the changing global climate.]]> Wed 28 Feb 2024 14:47:23 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:47997 Tue 14 Feb 2023 16:15:07 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:39230 −1 of As(V)]. Besides, it was observed that available soil phosphorus could positively affect the relative content of water-soluble, exchangeable and carbonate-bound arsenic. In the kinetics experiment, both the Michaelis-Menten constant (K_m) and maximum reaction velocity (V_max) of ALP increased with increasing As(V) concentration under four months ageing for each size aggregate. Multiple linear stepwise regression analysis between k_cat and the relative content of arsenic fraction indicated that carbonate-bound arsenic is the main fraction that inhibited the k_cat for macroaggregates (> 0.25 mm size). For soil aggregates of 0.1–0.25 mm size, k_cat increased with an increase in arsenic residual fraction. As for aggregates <0.1 mm size, Fe and Mn oxide-bound fraction is the main fraction that inhibited the k_cat. Overall, this study suggests carbonate-bound and Fe and Mn oxide-bound arsenic fractions could decrease the ALP activities via a decrease in the catalytic efficiency in macroaggregates and <0.1 mm size aggregates, respectively. Besides, available phosphorus should be considered as the main factor when assessing As biotoxicity and mobility.]]> Tue 09 Aug 2022 14:08:44 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:39279 max) ranged from 0.29 to 2.18 x 10⁻² mM g⁻¹ soil h⁻¹ and declined by 42.30%–71.01% under PTH stress. The Michaelis constant (K_m) values ranged between 2.90 and 14.17 x 10⁻² mM and exhibited three forms including unchanged, increased (38.16–242.65%) and decreased (13.41–39.23%) when exposed to PTH. Based on the changes in two kinetic parameters, the inhibition of PTH on FDA–H was classified as three types, i.e., noncompetitive, linear mixed and uncompetitive inhibition. The competitive inhibition constant (K_ic) and noncompetitive constant (K_iu) ranged from 0.064 to 0.447 mM and 0.209 to 0.723 mM, respectively, which were larger than the Km in values. The catalytic efficiency (V_max/K_m) of FDA–H is a sensitive integrated parameter to evaluate the PTH toxicity due to the higher inhibition ratio than the V_max. The PTH toxicity to FDA–H decreased with increase of soil organic matter and total nitrogen contents. This implied that the PTH toxicity could be alleviated by an increasing content of soil organic matter due to its buffering capacity to PTH. Besides, soils with a higher content of total nitrogen could provide stable environment for FDA–H to maintain its functionality under PTH pollution. Thus, the results of this study have great implications to the risk assessment of parathion in soils.]]> Thu 02 Jun 2022 15:12:26 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:39536 Mon 08 Aug 2022 11:27:21 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:41831 -1 and 400 mg kg^-1), F1 and F2 transformed to F4 and F5. Meanwhile, soil moisture had a significant influence on soil ALP activity. Soil ALP activity under 110% WHC was smaller than the activity of soil ALP under 35% WHC. The variation partitioning analysis (VPA) showed that soil moisture contributed 63.19% for this effect on soil ALP activity and was identified as the dominant factor. The value of ED 10 indicated that the As toxicity under 35% WHC was greater than that under 110% WHC. This could be due to that the excessive moisture content depressed soil ALP activity. Therefore, it is important to consider soil moisture content while assessing the As toxicity to soil ALP.]]> Fri 26 Aug 2022 11:21:16 AEST ]]>