Treatment of benzodiazepine withdrawal syndrome in a severe traumatic brain injury patient

Prolonged exposure to benzodiazepines (BDZ) may contribute towards physical dependence, which is manifested by iatrogenic Benzodiazepine Withdrawal Syndrome (BWS), a condition often underdiagnosed. Current evidence recommends precluding BDZ infusion as sedation in the intensive care unit to avoid possible withdrawal and delirium issues. Administration of dexmedetomidine should be considered to facilitate weaning in patients with BWS. © 2021 BMJ Publishing Group. All rights reserved

Processes of P mobility from Fitzgerald River catchment following application of different P rates

Phosphorus (P) export by erosion, surface runoff, throughflow and leaching are considered the main sources of P loss from agricultural land. The present study was conducted on the upper Fitzgerald River Catchment in the South coast region of Western Australia (WA) to examine the process of P mobilization at different P rates (0, 20 and 40 kg P/ha). Intact column leaching, packed box and field runoff plot studies were conducted on contrasting soils from the catchment. Soil solution was collected at 5, 10 and 15 cm by installing Rhizon soil solution samplers, and leachate collected at 30 cm. Runoff and soil solutions were analysed for particulate P (PP), dissolved reactive P (DRP), and total dissolved P (TDP) and dissolved organic P (DOP) was calculated by difference (TDP-DRP). Overall, DRP comprised <35 % of TP in runoff while about 90% or more of relative P losses via runoff, throughflow and leachate were in DOP and PP forms. The DOP and soluble organic carbon (SOC) in soil solution were well correlated in sand (R2 = 0.78, P <0.05) and clay soils (R2 = 0.56, P <0.05) at 0-5 cm suggesting that amounts of organic matter dissolved in soil solution influences P sorption and mobility. The higher PP concentration for the clay soil at the interface of clay and sandy layers indicates subsurface lateral flow is exacerbated by dispersive clay which might be an additional concern regarding P mobility in clay and duplex soils of the catchment. Ponding of water at the surface or lateral movement of water at the interface of sand and clay layers in the profile would increase the risk of P losses in the form of DP or PP in dispersion-prone sodic soils

Use soil test to inform change from phosphorus build-up to maintenance for more profits

Soils across the grains cropping regions of Western Australia were inherently low in P and other nutrients. Development of agriculture would not have been possible without the use of P and other fertilisers. In these soils, profitable rates of P resulted in increased yields and a gradual build-up of soil available P (measured as Colwell P). Once P deficiency is corrected and the Colwell P values for near maximum crop production (critical values) are reached, the recommended practice is to maintain the soil at these critical values. This prevents reversion to deficiency and risk of yield and profit loss. The P maintenance practice uses less P than the build-up phase. The amounts of P applied during maintenance are designed to balance (1) removal in harvested grains and other products such as hay and sheep sold off farm (2) amounts of fertiliser P that becomes tied-up by strong adsorption with soil and (3) unavoidable losses due to leaching, runoff and erosion. The WA cropping industry has a long history of P use that started with the development of the industry. It is now time to assess if we have succeeded in correcting the P deficiency and if we are ready to move to the maintenance phase. This is also an opportunity to assess what other soil constraints are limiting production and profits so that money freed-up by transitioning from build-up to maintenance could be re-invested in managing these constraints

Use of on-ground gamma-ray spectrometry to measure plant-available potassium and other topsoil attributes

The incidence of potassium (K) deficiency is increasing in crops, pastures, and forestry in south-western Australia. Although soil K can be measured using soil sampling and analysis, γ-ray spectrometry offers a potentially cheaper and spatially more precise alternative. This could be particularly useful in precision agriculture, where inputs are applied according to need rather than by general prescription. In a study of topsoils near Jerramungup, Western Australia, strong relationships (r2 = 0·9) were found between on-ground counts of γ-rays derived from 40K (γ-K) and both total K and plant-available K. The success of γ-ray spectrometry in predicting available K relied on a strong relationship (r2 = 0·9) between total K and available K which may not hold in all areas. Although the relationship between γ-K and available K held over the range of 36–1012 mg/kg, crop response to K fertilisers is only expected when the available K content is <100 mg/kg. Estimates of available K from γ-K were unreliable at this lower end of the regression curve. Separate analysis with a subset of the data with available K <100 mg/kg showed a poor relationship between γ-K and available K (r2 = 0·05; d.f. 11). The usefulness of γ-ray spectrometry may therefore be restricted to defining areas where response to fertiliser K may occur, and where further soil sampling and analysis are required to predict the fertiliser requirement. Strong relationships (r2 = 0·9) were also found between γ-K and a range of other soil attributes, including clay, silt, and organic carbon content. These relationships depended on the locally strong relationship between total K and these soil attributes. Since such relationships do not hold everywhere, the utility of γ-ray spectrometry will likewise be limited. Site-specific calibrations are required if γ-ray spectrometry is to be used for soil property mapping

Dissolved reactive phosphorus played a limited role in phosphorus transport via runoff, throughflow and leaching on contrasting cropping soils from southwest Australia

Purpose: Phosphorus (P) lost from agricultural land by erosion, runoff, throughflow and leaching is of major concern for water resource managers worldwide. Previous study on soils from cropping land of southwest Western Australia suggested P loss as dissolved unreactive P (DURP) via leaching, but the implications for processes and rates of P transport in soils are not known. Material and methods: Two contrasting soil profiles (sand and loam) from cropping land of southwest Western Australia were exposed to artificial rain in packed boxes and field runoff plots to examine P forms and fluxes in runoff, throughflow, leachate and soil solution after three P rates of application (equivalent to 0, 20 and 40. kg P/ha). Solutions were analyzed for total P (TP), dissolved reactive P (DRP) and total dissolved P (TDP). Particulate P (PP) and DURP were calculated by subtracting DRP from TP and TDP. Result and discussion: In the sand profile, about 90% or more of P losses via runoff and leachate were in DURP and PP forms, whereas DRP was a minor contributor. Phosphorus load in soil solution, throughflow, leachate and run-off increased with increasing P rate. The relatively higher affinity of soil for DRP compared to DURP might cause the latter to be more mobile through profile in association with colloidal compounds <. 0.2. μm. Higher PP concentration for loam soil via throughflow is exacerbated by dispersed clay, which could be an additional process influencing P mobility in loam and duplex soils. Conclusion: The DRP played a limited role in P transport compared to PP and DURP that both appeared to be associated with soil particles or soil colloids in runoff, throughflow, leachate and soil solution. Further characterization of the latter forms of P is needed so that management practices can be developed to minimize P losses