Enhancing carbon sequestration in soil with coal combustion products: a technology for minimising carbon footprints in coal-power generation and agriculture

Coal-fired power generation and agriculture account for more than half of global greenhouse gas emissions, but the coal fly ash (CFA) produced in the former can be a resource for reducing emissions from agriculture to minimise environmental footprints in both industries. Our aim in this study was to test how acidic and alkaline CFA addition could minimise loss of C and N from acidic soil, with or without added manure. We determined composition and structural characteristics of acidic and alkaline CFA for their capacity to adsorb organic carbon, but observed poor adsorption because of low concentrations of cenospheres and unburnt carbon as the primary absorbents in the ash. Addition of CFA had no impact on the loss of carbon or nitrogen from unmanured soil in which concentrations of these nutrients were low. Loss of carbon from manured soil was reduced by 36% with alkaline ashes and by 3-fold with acidic ashes; while loss of N was 30–50% lower with acidic ashes, but 28% higher with alkaline ashes, compared with no ash treatment. The increases in C sparing with CFA addition were achieved not by direct C absorption but by restraining microbial population and respiration, and potentially emissions. Alkaline CFA increased soil pH and if used to substitute just 10% of lime for ameliorating soil acidity would reduce CO2 emission associated with the mining of the lime and its eventual dissolution in soil by ~ 2.66 Tg or 2.8% of Australia’s annual agricultural emissions. High concentrations of oxides of phosphorus, silicon, titanium and clay particles in acidic ashes, and oxides of cations in alkaline ashes, were associated with potential for promoting C storage and acidity amelioration in soil

Knowledge Assessment of Anti-snake Venom Among Healthcare Practitioners in Northern Nigeria

Introduction: Anti-snake venom (ASV) is the standard therapy for the management of snakebite envenoming (SBE). Therefore, the knowledge of ASV among healthcare practitioners (HCPs) is essential for achieving optimal clinical outcomes in snakebite management. This study aimed to assess knowledge of ASV among the HCPs in northern Nigeria. Methods: We conducted a cross-sectional study involving eligible HCPs from different healthcare settings in northern Nigeria. The participants were recruited into the study using a combination of online (via Google Form) and face-to-face paper-based survey methods. The ASV knowledge of the respondents was measured using a validated anti-snake venom knowledge assessment tool (AKAT). Inadequate overall knowledge of ASV was defined as scores of 0-69.9%, and 70-100% were considered adequate overall knowledge scores. The predictors of ASV knowledge were determined using multiple logistic regression. Results: Three hundred and thirty-one (331) eligible HCPs were included in the study analysis (310 from online and 21 from paper-based survey). Overall, an estimated 12.7% of the participants had adequate knowledge of ASV. Adequate ASV knowledge was higher among physicians compared with other HCPs (21.7%; X-2 =8.1; p=0.04). Those without previous training on ASV (adjusted odds ratio [a0R], 0.37; 95% confidence interval [CI], 0.18-0.73; p= 0.004) and who have not previously administered/dispensed ASV (aOR, 0.31; 95% CI, 0.15-0.63; p \u3c 0.001) were less likely to have adequate knowledge of ASV. Conclusion: The knowledge of ASV among healthcare practitioners in northern Nigeria is grossly inadequate. Experience with administering or dispensing ASV predicts ASV knowledge. Therefore, appropriate interventions are needed to improve ASV knowledge, particularly among the HCPs, for optimal healthcare outcomes

Daily, seasonal and annual patterns of transpiration from a stand of remnant vegetation dominated by a coniferous Callitris species and a broad-leaved Eucalyptus species

Quantifying water use of native vegetation is an important contribution to understanding landscape ecohydrology. Few studies provide long-term (more than one growing season) estimates of water use and even fewer quantify interseasonal and interannual variation in transpiration. Globally, changes in land use are significantly altering landscape ecohydrology, resulting in problems such as dryland salinity and excessive groundwater recharge. Estimating stand water use is complex in multispecies forests, due to the differences in relationships among sapwood area, basal area and tree size for co-occurring species. In this article, we examine seasonal and interannual variation in transpiration rate of the tree canopy of two co-occurring species (a conifer Callitris glaucophylla J. Thompson & L.A.S. Johnson and a broad-leaved Eucalyptus crebra F. Muell.) in an open woodland in eastern Australia. Evapotranspiration of understorey species was measured using an open-top chamber, and tree water use was measured using heat-pulse sap flow sensors. Annual stand transpiration was 309 mm in 2003, a year of below average rainfall, and 629 mm in 2004, a year with higher-than-average rainfall. Despite an almost doubling (522 vs. 1062 mm) of annual rainfall between 2003 and 2004, annual tree water use remained a constant fraction (59%) of rainfall, indicative of compensatory mechanisms linking annual rainfall, leaf area index and tree water use. Deep drainage was estimated to be 4% of rainfall (20.8 mm) in 2003 and 2% (21.2 mm) in 2004, indicating that this native woodland was able to minimize deep drainage despite large interannual variability in rainfall.10 page(s

An analysis of the sensitivity of sap flux to soil and plant variables assessed for an Australian woodland using a soil-plant-atmosphere model

Daily and seasonal patterns of tree water use were measured for the two dominant tree species, 'Angophora bakeri' E.C.Hall (narrow-leaved apple) and 'Eucalyptus sclerophylla' (Blakely) L.A.S. Johnson & Blaxell (scribbly gum), in a temperate, open, evergreen woodland using sap flow sensors, along with information about soil, leaf, tree and micro-climatological variables. The aims of this work were to: (a) validate a soil-plant-atmosphere (SPA) model for the specific site; (b) determine the total depth from which water uptake must occur to achieve the observed rates of tree sap flow; (c) examine whether the water content of the upper soil profile was a significant determinant of daily rates of sap flow; and (d) examine the sensitivity of sap flow to several biotic factors. It was found that: (a) the SPA model was able to accurately replicate the hourly, daily and seasonal patterns of sap flow; (b) water uptake must have occurred from depths of up to 3 m; (c) sap flow was independent of the water content of the top 80 cm of the soil profile; and (d) sap flow was very sensitive to the leaf area of the stand, whole tree hydraulic conductance and the critical water potential of the leaves, but insensitive to stem capacitance and increases in root biomass. These results are important to future studies of the regulation of vegetation water use, landscape-scale behaviour of vegetation, and to water resource managers, because they allow testing of large-scale management options without the need for large-scale manipulations of vegetation cover

Root biomass distribution and soil properties of an open woodland on a duplex soil

Data on the distribution of root biomass are critical to understanding the ecophysiology of vegetation communities. This is particularly true when models are applied to describe ecohydrology and vegetation function. However, there is a paucity of such information across continental Australia. We quantified vertical and horizontal root biomass distribution in a woodland dominated by 'Angophora bakeri' and 'Eucalyptus sclerophylla' on the Cumberland Plains near Richmond, New South Wales. The site was characterised by a duplex (texture contrast) soil with the A horizon (to 70 cm) consisting of loamy sand and the B horizon (to > 10 m) consisting of sandy clay. The topsoil had a smaller bulk density, a smaller water holding capacity but a larger organic component and a larger hydraulic conductivity in comparison to the subsoil. Root biomass was sampled to 1.5 m depth and declined through the soil profile. Whilst total biomass in the B horizon was relatively small, its contribution to the function of the trees was highly significant. Coarse roots accounted for approximately 82% of the root mass recovered. Lateral distribution of fine roots was generally even but coarse roots were more likely to occur closer to tree stems. Variation in tree diameter explained 75% of the variation in total below-ground biomass. The trench method suggested the below-ground biomass was 6.03 ± 1.21 kg m⁻² but this method created bias towards sampling close to tree stems. We found that approximately 68% of root material was within a 2 m radius of tree stems and this made up 54% of the total number of samples but in reality, only approximately 5 to 10% of the site is within a 2 m radius of tree stems. Based on these proportions, our recalculated below-ground biomass was 2.93 ± 0.59 kg mm⁻². These measurements provide valuable data for modeling of ecosystem water use and productivity