Biochar amendment and water stress alter rhizosphere carbon and nitrogen budgets in bauxite-processing residue sand under rehabilitation

Nitrogen (N) bioavailability is one of the main limiting factors for microbial activity and vegetation establishment in bauxite-processing residue sand (BRS). Although beneficial effects of biochar on reducing N loss in the early stages of BRS rehabilitation have been observed previously, the underlying mechanisms of this complicated process, particularly the interactions between applied biochar and the plant rhizosphere is largely unknown. This glasshouse study (116 days), investigated the coupled effects of biochar and water stress on N bioavailability in the rhizosphere of ryegrass (Lolium rigidum) grown in BRS amended with di-ammonium phosphate (DAP) fertiliser (at rates of 0 or 2.7 t ha−1) with and without biochar amendment. The applied biochar was characterised as either aged acidic (AC) or alkaline pine (PC) and was mixed with BRS at a rate of 5% v/v under four moisture regimes (50%, 40%, 20% and 7.5% water holding capacity). Amending BRS with AC and PC biochars increased NH4 + retention and decreased cumulative NH3 volatilization within both the rhizosphere and root-free zones compared with fertiliser only treatment. These effects were more pronounced for the AC than PC biochar, suggesting that aged acidic biochar has the great potential for use in rapid establishment of vegetation in BRS disposal areas. The biochar amendment increased cumulative nitrous oxide emissions compared with DAP only treatment, with no significant differences among different moisture regimes. The Control and 20% water holding capacity (WHC) treatment showed the highest dissolved organic carbon (DOC) concentrations compared with other treatments and moisture regimes in the ryegrass rhizosphere, while the highest dissolved organic N concentration were observed in the DAP + AC treatment. Reducing moisture levels below 20% WHC generally decreased microbial biomass carbon (MBC) concentrations and activity in both the rhizosphere and root-free zones of all treatments, while total N generally decreased as moisture levels decreased from 50% to 7.5% WHC. Plant took up more N in the DAP + AC treatment compared with DAP + PC and DAP only treatments, while increasing water stress generally resulted in decreased aboveground biomass. © 201

Aged biochar alters nitrogen pathways in bauxite-processing residue sand: Environmental impact and biogeochemical mechanisms

Low nitrogen (N) content and retention in bauxite-processing residue sand (BRS) disposal areas pose a great challenge to the establishment of sustainable vegetation cover in this highly alkaline environment. The budget and fate of applied N in BRS and its potential environmental impacts are largely unknown. We investigated the effect of combined application of biochars [aged acidic (AC) vs alkaline pine (PC)] and di-ammonium phosphate (DAP) fertiliser on ammonia (NH3) volatilisation, nitrous oxide (N2O) emission and N retention in a 116-day glasshouse study. The application of AC to BRS decreased pH (≈0.5 units) in BRS, while PC biochar increased pH (≈0.3 units). The application of AC reduced NH3 volatilisation by ca. 80%, while PC by ca. 25%. On the other hand, the AC treatment increased N2O emission by 5 folds. However, the N loss via N2O emission in the AC treatment only accounted for ca. 0.4% of applied N. The reduction in BRS pH and increased retention of mineral N due to the presence of oxygen-containing (phenolic and carboxylic) functional groups in AC may be responsible for reduced NH3 volatilisation and increased N2O emission. This study has highlighted the potential of biochar (particularly aged biochar) in improving N retention and minimising environmental impacts in highly alkaline environments

The effect of dietary intake changes on nutritional status in acute leukaemia patients after first induction chemotherapy

This study aimed to evaluate how changes in dietary intake among acute lymphoblastic and acute myeloid leukaemia (ALL and AML) patients affect nutritional status after the first induction chemotherapy. Dietary intake was assessed using 24-h recall and a 136-item food frequency questionnaire. Nutritional status was assessed by Patients Subjective Global Assessment questionnaire before starting induction therapy and again after 1 month. All newly diagnosed acute leukaemia patients aged 15 years old and older who attended three referral hospitals for initiation of their induction chemotherapy were included in the sample selection provided that they gave informed consent. A total of 30 AML and 33 ALL patients participated in the study. Dietary intake and nutritional status worsened after the chemotherapy treatment. Dietary intake in terms of macronutrients, micronutrients, food variety and diet diversity score changed significantly after the induction chemotherapy. No significant relationship was found between the changes in dietary indices and nutritional status. Chemotherapy-related side effects as an additional factor to cancer itself could affect dietary intake of leukaemia patients. The effectiveness of an early assessment of nutritional status and dietary intake should be further investigated in order to deter further deterioration. © 2014 The Authors. European Journal of Cancer Care Published by John Wiley & Sons Ltd

Radiation-Free myeloablative allogeneic hematopoietic stem cell transplantation for adult acute lymphoblastic leukemia: A comparison of outcomes between patients with and without central nervous system involvement

For patients with acute lymphoblastic leukemia (ALL) undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT), total body irradiation (TBI) has been particularly advocated as a part of the conditioning regimen in case of extramedullary involvement in sanctuary sites such as the central nervous system (CNS), to ensure greater tissue penetration. In resource-limited countries lacking TBI facilities; however, ALL patients undergo radiation-free myeloablative conditioning, though its impacts on post-HSCT outcomes of the patients with pre-HSCT CNS involvement have not been analyzed. In this 14-year series of 278 adult (> 18 y) ALL patients undergoing TBI-free busulfan/cyclophosphamide conditioning allo-HSCT, we found that the long-term probabilities of overall survival, disease free survival, relapse and non-relapse mortality were not significantly different between CNS-involved and CNS-spared patients. Moreover, there was no statistically significant difference in the incidence of post-HSCT CNS relapse between CNS-involved and CNS-spared patients. Pre-HSCT cranial radiation therapy (CRT) showed no significant preventive effect on the likelihood of post-HSCT CNS relapse. Through multivariable regression analysis, grade III-IV acute graft-versus-host disease (GvHD), extensive chronic GvHD and post-HSCT relapse were ascertained as independent determinants of mortality (Adj.R2 = 53.9 , F(12,265) = 28.1, P < 0.001), while other parameters including Philadelphia translocation, pre-HSCT CNS involvement and CRT were found to have no independent effect. Although this study was not an attempt to compare TBI-based vs. non-TBI conditioning, the TBI-free myeloablative allo-HSCT was shown to be feasible and an option for adult ALL patients with CNS involvement, considering the comparable outcomes between patients with and without CNS involvement. © 2021 Elsevier Lt

Spatial and temporal dynamics of nutrients in riparian soils after nine years of operation of the Three Gorges Reservoir, China

The construction and operation of the Three Gorges Reservoir (TGR), the largest hydropower dam in the world, has had significant consequences for the hydrology of riparian zones along the Yangtze river. Little is known about how such changes in hydrology might affect the levels of nutrients and organic matter (OM) in riparian soils. We conducted a nine-year study on the spatio-temporal dynamics and dominant environmental correlates of nutrients and OM in riparian soils along a 600 km section of the Yangtze. These soils have been exposed to a disrupted hydrological regime since the TGR's establishment in 2008. Vegetation surveys were also conducted from 2012 to 2016 to assess relationships between soil chemical properties and vegetation community properties under altered hydrology. Across the stream gradient, concentrations of total potassium (K) increased by 54% since the TGR's establishment. The opposite occurred for SOM and available K, concentrations of which were 35% and 33% lower in 2016, respectively, than those of 2008. The rate of increase in total K tended to be more rapid at the middle section of the stream gradient. Moreover, concentrations of SOM, total N, total K, and available phosphorus (P) and K tended to be particularly high at the middle section. The spatio-temporal distributions of nutrients were strongly positively related to the contents of fine soil particles (i.e., silt and clay). Moreover, the aboveground biomass was negatively correlated with the nutrient dynamics. Our results indicate that the control of the nutrient release in the middle reaches and lower elevations where fine particles tend to accumulate, will be essential for maintaining the health of aquatic and riparian ecosystems upstream of the TGR. (C) 2019 Elsevier B.V. All rights reserved

Soil organic matter formation is controlled by the chemistry and bioavailability of organic carbon inputs across different land uses

Soil organic matter (SOM) formation involves microbial transformation of plant materials of various quality with physico-chemical stabilisation via soil aggregation. Land use and vegetation type can affect the litter chemistry and bioavailability of organic carbon (OC), and consequently influence the processing and stabilisation of OC into SOM. We used 13C nuclear magnetic resonance (13C NMR) and hot-water extraction to assess the changes in chemical composition and labile OC fractions during the transformation processes from leaf to litter to SOM depending on land use and vegetation type. The hot-water-extractable OC (HWEOC) decreased from leaf (43–65 g kg−1) to litter (19–23 g kg−1) to SOM (8–16 g kg−1) similar in four land use types: grassland, sugarcane, forest and banana. These trends demonstrated the uniform converging pathways of OC transformation and increasing stability by SOM formation. The preferential decomposition and decrease of labile OC fractions (∑% di-O-alkyl, O-alkyl and methoxyl) from leaf (54–69%) to SOM (41–43%) confirmed the increasing stability of the remaining compounds. Despite differences in the biochemical composition of the leaf tissues among the vegetation types, the proportions of labile OC fractions in SOM were similar across land uses. The OC content of soil was higher in forest (7.9%) and grassland (5.2%) compared to sugarcane (2.3%) and banana (3.0%). Consequently, the HWEOC per unit of soil weight was higher in forest and grassland (2.0 and 1.2 g kg−1 soil, respectively) compared to sugarcane and banana (0.3 and 0.4 g kg soil−1, respectively). The availability of labile SOM is dependent on the quantity of SOM not the chemical composition of SOM. In conclusion, labile OC fractions in SOM, as identified by 13C NMR, were similar across land use regardless of vegetation type and consequently, SOM formation leads to convergence of chemical composition despite diversity of OC sources

Soil organic matter formation is controlled by the chemistry and bioavailability of organic carbon inputs across different land uses

Soil organic matter (SOM) formation involves microbial transformation of plant materials of various quality with physico-chemical stabilisation via soil aggregation. Land use and vegetation type can affect the litter chemistry and bioavailability of organic carbon (OC), and consequently influence the processing and stabilisation of OC into SOM. We used 13C nuclear magnetic resonance (13C NMR) and hot-water extraction to assess the changes in chemical composition and labile OC fractions during the transformation processes from leaf to litter to SOM depending on land use and vegetation type. The hot-water-extractable OC (HWEOC) decreased from leaf (43–65 g kg−1) to litter (19–23 g kg−1) to SOM (8–16 g kg−1) similar in four land use types: grassland, sugarcane, forest and banana. These trends demonstrated the uniform converging pathways of OC transformation and increasing stability by SOM formation. The preferential decomposition and decrease of labile OC fractions (∑% di-O-alkyl, O-alkyl and methoxyl) from leaf (54–69%) to SOM (41–43%) confirmed the increasing stability of the remaining compounds. Despite differences in the biochemical composition of the leaf tissues among the vegetation types, the proportions of labile OC fractions in SOM were similar across land uses. The OC content of soil was higher in forest (7.9%) and grassland (5.2%) compared to sugarcane (2.3%) and banana (3.0%). Consequently, the HWEOC per unit of soil weight was higher in forest and grassland (2.0 and 1.2 g kg−1 soil, respectively) compared to sugarcane and banana (0.3 and 0.4 g kg soil−1, respectively). The availability of labile SOM is dependent on the quantity of SOM not the chemical composition of SOM. In conclusion, labile OC fractions in SOM, as identified by 13C NMR, were similar across land use regardless of vegetation type and consequently, SOM formation leads to convergence of chemical composition despite diversity of OC sources. © 2021 Elsevier B.V

Role of oxygen-containing functional groups in forest fire-generated and pyrolytic chars for immobilization of copper and nickel

Available online 9 November 2016Abstract not availableMaryam Esfandbod, Christopher R. Merritt, Mehran Rezaei Rashti, Balwant Singh, Sue E. Boyd, Prashant Srivastava, Christopher L. Brown, Orpheus M. Butler, Rai S. Kookana, Chengrong Che