O'Leary G.J.,Transport and Resources |
Liu L.,Australian Department of Primary Industries and Fisheries |
Ma Y.,Australian Department of Primary Industries and Fisheries |
Ma Y.,Nanjing University of Information Science and Technology |
And 8 more authors.
Geoderma | Year: 2016
We used the APSIM model to explore the ability to simulate soil organic carbon (SOC) from three long term agricultural experiments (LTAE) over 24-44years in eastern Australia (Hamilton Victoria, Wagga Wagga New South Wales and Warwick Queensland). The model was initialized for each location soil type using a 20-year spin-up period to reach stable SOC fractions. The model was not tuned to any of the data at each site. The cropping systems model simulated reasonably well the calculated changes in SOC over the 24-44-year period at the three different sites under various agronomic management practices. At Hamilton calculated SOC did not change significantly over 32years and the APSIM-Agpasture model represented this satisfactorily. Root mean square error was 4.9tCha-1 (0-30cm) (5.2%) ranging from 1.5 to 10.9tCha-1 (1.7 to 11.8%) over time. Similarly, over twenty-four years of continuous cropping at Wagga Wagga under a Wheat-Lupin crop rotation using APSIM-Wheat and APSIM-Lupin under stubble retention and zero tillage showed a largely neutral trend over time with RMSE of 3.4tCha-1 (0-30cm) (9.5%) ranging from 1.4 to 7.8tCha-1 (4 to 21%) over time. The SOC was much lower at Wagga Wagga compared to that at Hamilton. Forty-four years of continuous cropping at the Queensland site resulted in significant declines in SOC irrespective of the farming practices applied. However, the rates of decline were different with the least decline achieved from high N application with stubble retention. The modelled changes, using APSIM-Wheat and APSIM-Barley, in SOC matched reasonably well the calculated behaviour with the greatest decline under zero N application with overall RMSE of 4.1tCha-1 (0-30cm) (4.5%) ranging from 1.4 to 8.7tCha-1 (2 to 7%) over time. The biophysical simulation model exemplified by the APSIM model explained well the observed changes in SOC at the various locations without specifically fitting the model to the observed data, despite large variation in the calculated data. This indicates that the SOC model was robust over the moderate to long term period. As such the model is suitable to extrapolate a simulated response beyond these locations under various treatment combinations that should predict realistic SOC stocks within the expected mean error of less than 10% (3 to 6tCha-1 0-30cm). © 2015.
Rollins L.A.,Deakin University |
Rollins L.A.,University of New South Wales |
Woolnough A.P.,Transport and Resources |
Woolnough A.P.,Vertebrate Pest Research Section |
And 9 more authors.
Molecular Biology and Evolution | Year: 2016
Mitochondria are critical for life, yet their underlying evolutionary biology is poorly understood. In particular, little is known about interaction between two levels of evolution: between individuals and within individuals (competition between cells, mitochondria or mitochondrial DNA molecules). Rapid evolution is suspected to occur frequently in mitochondrial DNA, whose maternal inheritance predisposes advantageous mutations to sweep rapidly though populations. Rapid evolution is also predicted in response to changed selection regimes after species invasion or removal of pathogens or competitors. Here, using empirical and simulated data from a model invasive bird species, we provide the first demonstration of rapid selection on the mitochondrial genome within individuals in the wild. Further, we show differences in mitochondrial DNA copy number associated with competing genetic variants, which may provide a mechanism for selection. We provide evidence for three rarely documented phenomena: selection associated with mitochondrial DNA abundance, selection on the mitochondrial control region, and contemporary selection during invasion. © The Author(s) 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved.
Choy A.-L.,Transport and Resources |
Walker C.K.,Transport and Resources |
Panozzo J.F.,Transport and Resources
Cereal Chemistry | Year: 2015
The objectives of this study were to investigate the relationship between milling yield and grain hardness. A preliminary study was carried out with 20 samples (both hard and soft wheats) using the Brabender hardness tester (BHT) with two grind settings: one-step grind (0-10) and two-step grind (2-12: coarse; 0-8: fine). The two-step grind was correlated with particle size index, single-kernel characterization system (SKCS) hardness, break yield, and reduction yield (P < 0.05), whereas there was no correlation with the one-step grind method. An additional 64 samples were ground with the two-step grind setting to further validate this method. In terms of the BHT crush profile, no discernible differences were observed between varieties for the coarse grind, whereas for the fine grind, hard wheat gave a higher BHT maximum peak height and shorter grinding time compared with soft wheat. The break and reduction yields were significantly correlated with both BHT and SKCS hardness (P < 0.05). The findings indicated that the BHT method could be used to differentiate for milling yield among the different varieties. Based on the results, two milling yield models were developed, and both gave highly significant correlations between the predicted and Buhler mill break (R2 = 0.791, P < 0.05) and reduction yield (R2 = 0.896, P < 0.05). © 2015 AACC International, Inc.