495 research outputs found

    Evaluation of additives with bracken herbicides applied to Boomsprayer.

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    Treatments were applied in December 1987. Height of the Bracken made application by boom difficult due to inability to adequately raise the boom to give clearance. Some brushing of the Bracken with the boom was unavoidable. Assessment of the trial will be made in March 1988

    Crop oil additives to herbicides.

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    Crop oils have been used in agriculture for many years as carriers and spreaders for insecticides and fungicides, predominately in the horticultural industry. Recently they have gained prominence in broad scale agriculture in Western Australia as additives to herbicides in many and varied situations. Western Australian farmers have been keen to use crop oils because of the potential they offer to: Improve the efficacy of herbicides and possibly allow herbicide rate reductions. Make herbicides more robust, particularly under adverse spraying conditions. Prevent herbicide drift and off-target damage

    Post emergence weed control in lupins.

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    As a general assessment in can be said that Tigrex is a safe and efficient herbicide for control of radish in wheat. Brodal alone was generally unsatisfactory for radish control. While Diuron + Brodal was safe and efficient, Ally and Brodal should not be used together. Diuron + MCPA gave poorer control than one would normally expect.87WH6

    A comparison of filtration rates among pelagic tunicates using kinematic measurements

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    Author Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Marine Biology 157 (2010): 755-764, doi:10.1007/s00227-009-1359-y.Salps have higher filtration rates than most other holoplankton, and are capable of packaging and exporting primary production from surface waters. A method of kinematic analysis was employed to accurately measure salp feeding rates. The data were then used to explain how diverse body morphologies and swimming motions among species and lifecycle stages influence salp feeding performance. We selected five species, representing a range of morphologies and swimming styles, and used digitized outlines from video frames to measure body-shape change during a pulse cycle. Time-varying body volume was then calculated from the digitized salp outlines to estimate the amount of fluid passing through the filtering mesh. This non-invasive method produced higher feeding rates than other methods and revealed that body volume, pulse frequency and degree of contraction are important factors for determining volume filtered. Each species possessed a unique combination of these three characteristics that resulted in comparable filtration (range: 0.44 - 15.33 ml s-1) and normalized filtration rates (range: 0.21 – 1.27 s-1) across species. The convergence of different species with diverse morphologies on similar normalized filtration suggests a tendency towards a flow optimum.This work was supported by NSF project OCE-0647723

    Composition and degradation of salp fecal pellets: Implications for vertical flux in oceanic environments

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    Changes in the sinking rates, ash-free dry weights, particulate carbon and nitrogen content, and carbon:nitrogen ratios from the fecal pellets of several species of oceanic salps were examined in ten-day decomposition studies. Although bacteria and protozoa became abundant in the incubation vessels, most of the fecal pellets remained physically intact throughout the study. Bacterial activity in the pellets (measured by the rate of uptake of 3H-thymidine) increased, but microbial degradation had little effect on the sinking speeds of most of the fecal pellets. The average losses of ash-free dry weight and carbon and nitrogen content, along with changes in carbon:nitrogen ratio, were small compared to their initial values. We conclude that microbial degradation of large salp fecal pellets would not prevent the vertical flux to the deep ocean of a significant fraction of the particulate organic material contained in the pellets. The fecal pellets of oceanic salps provide a rapid, and potentially important, mechanism for the consolidation and vertical transport of organic and lithogenic material associated with minute particles in the open ocean

    Marine Reserves Shape Seascapes on Scales Visible From Space

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    Marine reserves can effectively restore harvested populations, and ‘mega-reserves’ increasingly protect large tracts of ocean. However, no method exists of monitoring ecological responses at this large scale. Herbivory is a key mechanism structuring ecosystems, and this consumer–resource interaction\u27s strength on coral reefs can indicate ecosystem health. We screened 1372, and measured features of 214, reefs throughout Australia\u27s Great Barrier Reef using high-resolution satellite imagery, combined with remote underwater videography and assays on a subset, to quantify the prevalence, size and potential causes of ‘grazing halos’. Halos are known to be seascape-scale footprints of herbivory and other ecological interactions. Here we show that these halo-like footprints are more prevalent in reserves, particularly older ones (approx. 40 years old), resulting in predictable changes to reef habitat at scales visible from space. While the direct mechanisms for this pattern are relatively clear, the indirect mechanisms remain untested. By combining remote sensing and behavioural ecology, our findings demonstrate that reserves can shape large-scale habitat structure by altering herbivores\u27 functional importance, suggesting that reserves may have greater value in restoring ecosystems than previously appreciated. Additionally, our results show that we can now detect macro-patterns in reef species interactions using freely available satellite imagery. Low-cost, ecosystem-level observation tools will be critical as reserves increase in number and scope; further investigation into whether halos may help seems warranted. Significance statement: Marine reserves are a widely used tool to mitigate fishing impacts on marine ecosystems. Predicting reserves\u27 large-scale effects on habitat structure and ecosystem functioning is a major challenge, however, because these effects unfold over longer and larger scales than most ecological studies. We use a unique approach merging remote sensing and behavioural ecology to detect ecosystem change within reserves in Australia\u27s vast Great Barrier Reef. We find evidence of changes in reefs\u27 algal habitat structure occurring over large spatial (thousands of kilometres) and temporal (40+ years) scales, demonstrating that reserves can alter herbivory and habitat structure in predictable ways. This approach demonstrates that we can now detect aspects of reefs\u27 ecological responses to protection even in remote and inaccessible reefs globally

    Rates of Ally and Glean for cape tulip control.

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    Evaluation in 1987 indicated that Ally and Glean at all rates gave 100% control of Cape Tulip at York with minimal pasture affect on species other than clover.87NO110, 87NO110(1), 87NO110(2), 87NO110(3

    Wild oat control with Hoegrass with and without oil

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    Trial 87NO08All treatments except Combine + Oil yielded significantly better than the control. Control of wild oats with Grasp was superior to many other treatments and this was reflected in the yield. Trial 87N009All treatments yielded significantly better than the control however there was no difference between herbicides, rates of use or additives. The exception being 0.75 L Hoegrass +WA which yielded significantly less than Grasp + oil

    Tolerance of cereal varieties to Hoegrass + oil

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    Almost invariably, Hoegrass applied to wheat and barley varieties reduced crop vigour assessed ten weeks after spraying.87A34(1

    Crop establishment

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    Trial effect of timing of Roundup CT and Spray.Seed application and cultivation on crop establishment and growth.87WH53, 87NO85 The general tendency was for yield to decrease as the time to seeding after Spray.Seed application increased.For trial 87NO85 the site was a \u27problem\u27, heavy textured soil where crop emergence problems following glyphosate had been experienced in previous years. Crop establishment - time of seeding following herbicide application.87A37 Use of a knockdown herbicide greatly increased yield when compared to the unsprayed treatments. Further work is required to resolve contrasting results
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