Quantifying the economic impact of soil constraints on Australian agriculture: a case study of wheat

Soil sodicity, acidity, and salinity are important soil constraints to wheat production in many cropping regions across Australia, and the Australian agricultural industry needs accurate information on their economic impacts to guide investment decisions on remediation and minimize productivity losses. We present a modelling framework that maps the effects of soil constraints on wheat yield, quantifying forfeited wheat yields due to specific soil constraints at a broad spatial scale and assessing the economic benefit of managing these constraints. Of the three soil constraints considered (sodicity, acidity, and salinity), sodicity caused the largest magnitude of yield gaps across most of the wheat-cropping areas of Australia, with an average yield gap of 0.13\ua0t hayr. Yield gaps due to acidity were more concentrated spatially in the high-rainfall regions of Western Australia, Victoria, and New South Wales, and averaged 0.04\ua0t hayr across the wheat-cropping areas of Australia, whereas the yield gap due to salinity was estimated to be 0.02\ua0t hayr. The lost opportunity associated with soil sodicity for wheat production was estimated to be worth A$1,300 million per annum, for soil acidity, A$400 million per annum, and for salinity, A$200 million per annum. The results of this work should prove useful to guide national investment decisions on the allocation of resources and to target areas where more detailed information would be required in order to reduce the yield gap associated with soil constraints on wheat yields in Australia

Exorotated radiographic views have additional diagnostic value in detecting an osseous impediment in patients with posterior ankle impingement

Objectives A standard lateral radiograph is the first step in the diagnostic workup in patients with posterior ankle pain. Because of overprojection by other structures at suboptimal radiographic projection angle, often an os trigonum is not discovered or erroneously be mistaken for a hypertrophic posterior talar process. The aim of this study was to identify the projection angles at which a radiograph is optimal for detecting bony impediments in patients suffering from posterior ankle impingement. Methods Using ankle CT scans of patients with posterior ankle impingement, digitally reconstructed radiographs (DRRs) simulating 13 different radiographic projection angles were generated. The ankle CT scans served as a reference for the detection of an os trigonum and hypertrophic posterior talar process. Members of the Ankleplatform Study Group were invited to assess the DRRs, for presence or absence of an os trigonum or hypertrophic posterior talar process. Diagnostic accuracy and interobserver reliability were estimated for each projection angle. In addition, the diagnostic accuracy of the standard lateral view in combination with the rotated views was calculated. Results High sensitivity for detecting an os trigonum was found for +15° (90.3%), +20° (81.7%) and +25° (89.7%) degrees of exorotation. Specificity in this range of projection angles was between 89.6% and 97.8%. Regarding the presence of a hypertrophic posterior talar process, increased sensitivity was found for +15° (65.7%), +20° (61.0%), +25° (60.7%), +30° (56.3%) and +35° (54.5%). Specificity ranged from 78.0% to 94.7%. The combination of the standard lateral view in combination with exorotated views showed higher sensitivity. For detecting an os trigonum, a negative predictive value of 94.6% (+15°), 94.1% (+20°) and 96.1% (+25°) was found. Conclusion This study underlines the additional diagnostic value of exorotated views instead of, or in addition to the standard lateral view in detecting an osseous impediment. We recommend to use the 25° exorotated view in combination with the routine standard lateral ankle view in the workup of patients with posterior ankle pain. Level of evidence Level III