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Koerber G.R.,University of South Australia | Seekamp J.V.,University of South Australia | Anderson P.A.,University of South Australia | Whalen M.A.,University of South Australia | And 2 more authors.
Australian Journal of Botany | Year: 2012

A putative hybrid between Eucalyptus largiflorens F.Muell. and Eucalyptus gracilis F.Muell., called green box, has attracted attention for its ability to grow on the salt- and drought-affected Chowilla floodplain of the Murray River in South Australia. Relationships between carbon isotope discrimination (Δ13C) and the ratio of substomatal to ambient CO2 (ci/ca) indicated that green box was not as water use efficient as E. largiflorens. Specific leaf area of green box and E. gracilis was significantly lower compared with E. largiflorens (38.38 and 36.96 versus 43.71cm 2g-1). Leaf nitrogen for green box and E. gracilis was significantly lower compared with E. largiflorens (12.66 and 11.35 versus 15.07mgg-1 dry weight, P=0.004 and 0.001, respectively) and leaf carbon of E. gracilis was significantly higher compared with green box and E. largiflorens (541.75 versus 514.90 and 519.82mgg-1 dry weight, P=0.002 and 0.011 respectively). There were significantly (P=0.016) more occurrences of elevated ci/ca below a minimum gs in E. gracilis compared with E. largiflorens, with green box being intermediate (means=21.6, 6.8 and 9.4). After 10 years, E. largiflorens trunk circumference had significantly increased (P=0.017) and height had significantly decreased (P=0.026) due to visible dieback. Green box and E. gracilis grew slower, conserving resources, illustrating a useful strategy to consider when choosing plants for revegetation efforts. © 2012 CSIRO. Source


Panten K.,CSIRO | Panten K.,Cooperative Research Center for Viticulture | Panten K.,JKI Institute for Crop and Soil Science | Bramley R.G.V.,CSIRO | And 3 more authors.
Precision Agriculture | Year: 2010

Precision agriculture (PA) offers opportunities for the development of new approaches to on-farm experimentation to assist farmers with site-specific management decisions. Traditional agricultural experiments are usually implemented in fields with the least possible soil heterogeneity under the assumption that responses to inputs and inherent variation of the soil are additive components of yield variation. However, because the soil in typical fields is not homogeneous, PA has much to offer. Farmers faced with variable conditions need to optimize their management to the variation over space and time on their farm, a problem that is not solved by conventional approaches to experimentation. New designs for on-farm experiments were developed in the 1990s for cereal production in which the whole field was used for the experiment rather than small plots. We explore the extension of this type of experiment to a vineyard in the Clare Valley of South Australia aiming to evaluate options to increase grape yield and vine vigour. Manually sampled indices of vine performance measured on georeferenced 'target' grapevines were analysed geostatistically. The major advantage of such an approach is that the spatial variation in response to experimental treatments can be examined. Linear models of coregionalization, pseudo cross-variograms and standardized ordinary cokriging are used to map treatment responses over the experimental area and also the differences between them. The results indicate that both treatment responses and the significance of differences between them are spatially variable. Thus, we conclude that whole-of-block on-farm trials are useful in vineyards. © 2009 Springer Science+Business Media, LLC. Source


Stevens R.M.,South Australian Research And Development Institute | Stevens R.M.,Cooperative Research Center for Viticulture | Stevens R.M.,Sentek Pty Ltd | Pech J.M.,South Australian Research And Development Institute | And 9 more authors.
Australian Journal of Grape and Wine Research | Year: 2016

Background and Aims: We investigated rootstock effects on the response of fruit and wine composition to reduced irrigation in vines growing on saline soil. Methods and Results: Drip-irrigated Shiraz vines on five rootstocks were subjected to industry standard and 30% reduced irrigation over four consecutive seasons. Fruit composition during berry shrivel and at harvest was assessed in each season and wine was made and assessed in two seasons. Rootstock and irrigation independently affected fruit anthocyanins concentration and wine spectral properties. In two seasons, reduced irrigation affected the accumulation of anthocyanins and total soluble solids during berry shrivel. Fruit from 110 Richter had a 16% higher concentration of anthocyanins and wine a 29% higher colour density than that of fruit and wine from Ramsey. Sodium and chloride concentration in wine from 110 Richter was 27 and 50% less than in wine from Ramsey. In one of two seasons, reducing irrigation improved the sensory score from wines on 110 Richter and 140 Ruggeri rootstocks. Yield and berry mass accounted for 25% and less than 1%, respectively, of the variation in concentration of fruit anthocyanins over four seasons. Conclusion: Reducing irrigation and substitution of 110 Richter for Ramsey rootstock both improved fruit composition, but reduced yield. In the early 2000s, the extra payment for higher quality did not offset the loss due to lower yield. Significance of the Study: Wine from vines on 110 Richter had higher colour and a lower concentration of sodium and chloride than that wine from vines on Ramsey. © 2016 Australian Society of Viticulture and Oenology Inc. Source

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