Nitrogen composition in furrow irrigated run-off water
AGRICULTURAL WATER MANAGEMENT
Authors: Macdonald, B. C. T.; Nachimuthu, G.; Chang, Y. F.; Nadelko, A. J.; Tuomi, S.; Watkins, M.
Furrow irrigation in cotton growing vertosols is the most preferred method in Australia. After fertilisation, irrigation water interacts with the soil which can dissolve nitrogen (N) compounds into the run-off water. The run-off or tail water that leaves the field is enriched with N and can reduce crop N use efficiency. During 2014 - 2015 and 2015 - 2016 N solute concentration in the irrigation water and run-off was measured in a tillage cropping rotation experiment. In the continuous cotton treatments (2014 - 2015) when urea was broadcast on the surface of furrow irrigated cotton system, 11 % of the applied fertiliser (260 kg N ha(-1)) was lost from the field in the tail water. Most of the losses from the soil occurred during the first irrigation as nitrate and urea. The irrigation water supplied 10 kg dissolved organic nitrogen (DON) kg N ha(-1) to the field. During 2015 - 2016, when subsurface banding of the urea was used, losses equated to 5 % of applied N, in irrigated continuous cotton treatments. In a second crop treatment, an irrigated maize rotation, the broadcasted urea was leached into the soil by rainfall before a 100 mm irrigation event. The run-off losses were less than the sub surface urea banding and in this treatment were 0.5 % of the applied fertiliser. The study shows that DON-N, NO3-N, NH4-N, Urea-N are dissolved from the soil in cotton production systems and lost to furrow irrigation runoff. This dissolved N maybe denitrified in the cotton irrigation network if the tail water is not reused quickly. The results show that N contributions from irrigation water need to be accounted for overall N budget of the cotton farm to improve the N use efficiency.
Is Total Hip Arthroplasty a Cost-Effective Option for Management of Displaced Femoral Neck Fractures? A Trial-Based Analysis of the HEALTH Study
JOURNAL OF ORTHOPAEDIC TRAUMA
Authors: Axelrod, Daniel; Tarride, Jean-eric; Ekhtiari, Seper; Blackhouse, Gordon; Johal, Herman; Bzovsky, Sofia; Schemitsch, Emil H.; Heels-Ansdell, Diane; Bhandari, Mohit; Sprague, Sheila
Background: Displaced femoral neck fractures are a significant source of morbidity and mortality and can be treated with either hemiarthroplasty (HA) or total hip arthroplasty (THA). Proponents of THA have argued THA offers lower risk of revision, with improved functional outcomes when compared to HA. To evaluate cost effectiveness of THA compared with HA, a trial-based economic analysis of the HEALTH study was undertaken. Methods: Health care resource utilization (HRU) and health-related quality of life (HRQoL) data were collected postoperatively and costed using publicly available databases. Using EuroQol-5 Dimensions (EQ-5D) scores, we derived quality adjusted life years (QALYs). A 1.5% discount rate to both costs and QALYs was applied. Age analyses per age group were conducted. All costs are reported in 2019 Canadian dollars. Results: When compared with HA, THA was not cost-effective for all patients with displaced femoral neck fractures ($150,000/QALY gained). If decision makers were willing to spend $50,000 or $100,000 to gain one QALY, the probability of THA being cost-effective was 12.8% and 32.8%, respectively. In a subgroup of patients younger than 73 (first quartile), THA was both more effective and less costly. Otherwise, THA was more expensive and yielded marginal HRQoL gains. Conclusions: Our results suggest that for most patients, THA is not a cost-effective treatment for displaced femoral neck fracture management versus HA. However, THA may be cost effective for younger patients. These patients experience more meaningful improvements in quality of life with less associated cost because of shorter hospital stay and fewer postoperative complications.