When is the price right?

Demand and Price Analysis,

Feral goats in south-western Queensland: a permanent component of the grazing lands

Feral goats were harvested in south-western Queensland at four sites under two regimes (opportunistic harvesting and sustained control). We assessed how this impacted on their contribution to total grazing pressure, on soil and pasture conditions and on the economics of goat management. The population impact was not consistent across sites with the same treatment, with 62% and 84% reductions in numbers in the two northern sites (one opportunistic harvesting site and one sustained control site) while numbers in the southern sites essentially remained the same. The contribution of goats to grazing pressure ranged from 3 to 30%; kangaroos contributed 16–36%; and livestock contributed 37–72%. Harvest rates of feral goats calculated for each of the sites ranged from 17 to 41%. There was no consistent relationship between population changes and the harvest rates. Seasonal conditions had greater influence on pasture and soil conditions than did changes in feral goat populations. The average cost of mustering goats (based on 34 operations) was $1.93 per head. Mustering costs increased markedly when goat density was lower than 10/km2. Average trapping costs (based on 7 trapping programs) were$2.08 per head. This compared with on-farm prices of $16–$25 per head in 1997. Personal circumstances and preferences of individual landholders were the key determinant of the level of control undertaken. Variability in price contributed to landholders being apprehensive about the viability of the goat industry. There are few simple tools available for landholders to estimate feral goat numbers and this makes effective management of total grazing pressure difficult

New Approach for Boat Motion Analysis in Rowing

In rowing, the study of the movement of the boat and of the rower in the boat is difficult. Indeed, the shell is quite narrow and fragile and it is impossible to use the classical apparatus for physiological and biomechanical analysis. For this reason, the physiological studies of rowers (cardiac and pulmonary parameters) have been more easily realised on specific and non specific ergometers (see Hagerman for an extensive review 1984): it is well known now, that rowers have exceptional aerobic possibilities and also use anaerobiosis for the start and the final part of the race (Hagerman 1984). In contrast, only a few publications deal with the movement of the boat and the rower. The velocity of the boat at different stroke rates (Martin and Bernfield 1980), the angular velocities of various articulations of the rowers (Nelson and Widule 1983) were studied by kinematic analysis. Though this technique is very useful, it does not catch the movements behind the subjects and is of no use to record physiological and mechanical parameters (Ishiko 1967). Some authors used DC recorder placed in a motor boat following the racing shell to record different parameters (Baird and Soroka 1952; Di Prampero 1971; Celentano 1974). But, this technique is not practical because of the need of a second operator to keep the cables out of the water. With the miniaturization, Ishiko proposed and used multichanneltelemetry to record the force of the rower and the acceleration of the boat (Ishiko 1967; Ishiko 1971). Schneider also used the same technique to record the force of the rower in the boat (Schneider 1978). Though this technique is excellent and powerful, it is also very expensive and quite sophisticated. Our goal was thus to take advantage of the miniaturization of the elements and to build and use a recorder and transducers that can be placed into the boat to record the acceleration of the boat and the propulsive force of the rower

Micro-Water harvesting and soil amendment increase grain yields of barley on a Heavy-Textured alkaline sodic soil in a rainfed Mediterranean environment

This paper focuses on the adverse effects of soil sodicity and alkalinity on the growth of barley (Hordeum vulgare L.) in a rainfed environment in south-western Australia. These conditions cause the accumulation of salt (called ‘transient salinity’) in the root zone, which decreases the solute potential of the soil solution, particularly at the end of the growing season as the soil dries. We hypothesized that two approaches could help overcome this stress: (a) improved micro-water harvesting at the soil surface, which would help maintain soil hydration, decreasing the salinity of the soil solution, and (b) soil amelioration using small amounts of gypsum, elemental sulfur or gypsum plus elemental sulfur, which would ensure greater salt leaching. In our experiments, improved micro-water harvesting was achieved using a tillage technique consisting of exaggerated mounds between furrows and the covering of these mounds with plastic sheeting. The combination of the mounds and the application of a low rate of gypsum in the furrow (50 kg ha−1) increased yields of barley grain by 70% in 2019 and by 57% in 2020, relative to a control treatment with conventional tillage, no plastic sheeting and no amendment. These increases in yield were related to changes in ion concentrations in the soil and to changes in apparent electrical conductivity measured with the EM3

Vroege bepaling van de effectiviteit van ALS-remmende herbiciden

MLHD, de methode om lage herbicide doseringen op maat en met controle op effectiviteit toe te passen is specifiek ontwikkeld voor fotosynthese-remmers. Telers ervaren de beperkte toepasbaarheid van de methodiek soms als bezwaar. Via onderzoek worden de mogelijkheden om MLHD te verbreden naar middelen met andere werkingsmechanismen verkend. In dit artikel wordt een overzicht gegeven van dergelijk onderzoek gericht op ALS(AcetoLactaatsynthase)-remmende herbicide

Kritisch doseren van herbiciden volgens MLHD

De minimum effectieve dosering van een herbicide wordt bepaald door een complex van factoren zoals onkruidsoorten, onkruidgrootte, gewasstadium, weersomstandigheden, spuittechniek, formulering en hulpstoffen. In dit artikel wordt nader ingegaan op het Minimum Letale Herbicide Docering (MLHD) concept. MLHD is de laatste jaren ontwikkeld met als doel (vooral via sensingtechnieken) herbicidengebruik rationeler en duurzamer te make

Nano-surgery at the leukocyte–endothelial docking site

The endothelium has an important role in controlling the extravasation of leukocytes from blood to tissues. Endothelial permeability for leukocytes is influenced by transmembrane proteins that control inter-endothelial adhesion, as well as steps of the leukocyte transmigration process. In a cascade consisting of leukocyte rolling, adhesion, firm adhesion, and diapedesis, a new step was recently introduced, the formation of a docking structure or “transmigratory cup.” Both terms describe a structure formed by endothelial pseudopods embracing the leukocyte. It has been found associated with both para- and transcellular diapedesis. The aim of this study was to characterize the leukocyte–endothelial contact area in terms of morphology and cell mechanics to investigate how the endothelial cytoskeleton reorganizes to engulf the leukocyte. We used atomic force microscopy (AFM) to selectively remove the leukocyte and then analyze the underlying cell at this specific spot. Firmly attached leukocytes could be removed by AFM nanomanipulation. In few cases, this exposed 8–12 μm wide and 1 μm deep footprints, representing the cup-like docking structure. Some of them were located near endothelial cell junctions. The interaction area did not exhibit significant alterations neither morphologically nor mechanically as compared to the surrounding cell surface. In conclusion, the endothelial invagination is formed without a net depolymerization of f-actin, as endothelial softening at the site of adhesion does not seem to be involved. Moreover, there were no cases of phagocytotic engulfment, but instead the formation of a transmigratory channel could be observed

Crop Updates - 2003 Oilseeds

This session covers fifteen papers from different authors ACKNOWLEDGMENTS VARIETIES Large scale canola varietal evaluation in WA, Peter Nelson, Oilseeds WA Performance of IT and TT canola varieties in the medium and high rainfall agzones of WA 2001-02, Graham Walton, Hasan Zaheer and Paul Carmody, Department of Agriculture QUALITY Reproductive biology, cotyledon development and oil accumulation in canola, J.A. Fortescue and D.W. Turner, School of Plant Biology, Faculty of Natural and Agricultural Sciences, The University of Western Australia Plant and environmental factors affecting oil concentration in canola – a mini-review, D.W. Turner, School of Plant Biology, Faculty of Natural and Agricultural Sciences, The University of Western Australia Potential benefits from interspecific crosses between canola and ‘near canola’ quality Indian mustard, Janet Wroth, School of Plant Biology, The University of Western Australia (UWA), Wallace Cowling, School of Plant Biology, UWA and CBWA Pty Ltd, Anh-Van Pham, School of Mathematics and Statistics, UWA NUTRITION, AGRONOMY AND MACHINERY Timing of nitrogen application for producing canola grain and oil, R. F. Brennan, Department of Agriculture Managing canola for soil type and moisture stress, Paul Carmody and Hasan Zaheer Department of Agriculture Machinery lessons from 2002 – canola establishment, Glen Riethmuller, Greg Hamilton and Jo Hawksley, Department of Agriculture Machinery lessons from 2002 – harvesting short crops, Glen Riethmuller, Department of Agriculture Does increasing canola seeding rate reduce the competitiveness of grass weeds? Zaicou-Kunesch, C.M., Zaheer, S.H. and Eksteen, D, Department of Agriculture PESTS AND DISEASES Aphid damage to canola – not all cultivars are equal, Françoise A. Berlandier and Christiaan Valentine, Department of Agriculture Should we be worried about developing insecticide resistance in aphids? Owain Edwards, CSIRO Entomology Benefits provided by treating canola seed with imidacloprid seed dressing, Roger Jones, Brenda Coutts, Lisa Smith and Jenny Hawkes, Department of Agriculture, and Centre for Legumes in Mediterranean Agriculture Blackleg levels in canola in 2002, Ravjit Khangura1, Moin Salam1, Art J Diggle1 and Martin J Barbetti1,2 1Department of Agriculture, 2University of Western Australia DBM in canola, Kevin Walden, Department of Agricultur