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Guerrero-Rodriguez J.D.D.,University of Adelaide | Guerrero-Rodriguez J.D.D.,Cooperative Research Center for Plant based Management of Dryland Salinity | Revell D.K.,University of Adelaide | Revell D.K.,Cooperative Research Center for Plant based Management of Dryland Salinity | And 3 more authors.
Animal Feed Science and Technology | Year: 2011

Most glycophytic forage legumes exhibit large reductions in biomass in response to saline growing conditions, although differences among species in salt tolerance exist. As several plant metabolic processes are affected by salinity, the nutritive value of these species to animals may be altered. Mineral concentration is an important component of plant nutritive value, and was evaluated in lucerne and white melilot under salt concentrations of 0, 55 and 110. mM NaCl in a glasshouse. Lucerne consistently accumulated higher concentrations of Na and Cl than white melilot. Calculated NaCl concentrations per unit DM reached 125. g/kg in lucerne and 39. g/kg in white melilot when irrigated with water containing 110. mM NaCl. In leaves of both species the Ca and Mg concentration decreased (P < 0.0001) with increasing salinity level, and there was an interaction (P < 0.0001) for these elements in which lucerne stems had decreases. The P concentration increased (P < 0.0001) in both species and the K concentration was affected only in lucerne stems. Among trace elements, Zn and Fe had marked decreases. Leaf and stem Zn concentration decreased in both species and Fe decreased more in leaves than in stems, but most analyzed microelements remained at acceptable levels for animal production. Detrimental changes in the mineral composition of forage species in response to salinity can be minimized by selecting appropriate species, such as white melilot. This may lead to improved animal production if biomass production, voluntary animal intake and digestibility can be maintained. © 2011 Elsevier B.V.

Feikema P.M.,University of Melbourne | Feikema P.M.,Cooperative Research Center for Plant Based Management of Dryland Salinity | Sasse J.M.,Sassafras Group
New Forests | Year: 2012

Eucalyptus camaldulensis × globulus and E. camaldulensis × grandis hybrids have been developed to combine the salt-waterlogging tolerance and high-quality wood fibre of their respective parents. The aim is to develop trees that will grow in relatively dry and/or saline environments and provide commercial wood products. Previous studies indicate that the hybrids exhibit faster growth than either of their pure species parents, and that there are significant differences in growth rates between them. We undertook a comparative study of the partitioning of above-ground biomass (AGB) to examine biomass and chloride (Cl) allocation of trees growing on two saline-irrigated sites in south-eastern Australia. Eucalyptus camaldulensis × globulus had a higher proportion of AGB in leaves (20-29% cf. 15-16%), and lower proportion in live branches (3-10% cf. 6-14%) than E. camaldulensis × grandis. The concentration of Cl was highest in the stembark (4. 2-9. 6 g kg -1) and lowest in the stemwood (0. 6-2. 0 g kg -1), suggesting that trees can export Cl through bark shedding. Total Cl content was strongly related to volume under bark (R 2 = 0. 99), and differences in partitioning of Cl into tree components differed between the hybrids in the same way as AGB. Preferential partitioning of Cl to live branches rather than foliage in E. camaldulensis × grandis suggests that this hybrid may be compartmentalising Cl to reduce the risk of Cl toxicity in the leaves. © 2011 Springer Science+Business Media B.V.

Yunusa I.A.M.,University of Technology, Sydney | Yunusa I.A.M.,Cooperative Research Center for Plant Based Management of Dryland Salinity | Aumann C.D.,Australian Department of Primary Industries and Fisheries | Aumann C.D.,Cooperative Research Center for Plant Based Management of Dryland Salinity | And 8 more authors.
Agricultural and Forest Meteorology | Year: 2010

Understanding the strategies that confer resilience on natural woodlands in drought prone environments is important for the conservation of these and similar ecosystems. Our main aim in this 2-year study was to assess traits (sapwood area, sapwood density and leaf area index) that control transpiration in Eucalyptus camaldulensis and E. microcarpa in a natural forest in which topographical variation created surface soils of sandy clay in a depression (clay-zone) and of loamy sand underlain by a dense profile on the terraces (sand-zone). The clay-zone had a wetter profile due to extra water supply through subsurface lateral flow from the adjoining, topographically higher, sand-zone. In the clay-zone, the differences between the two tree species in their hydraulic attributes were large and rates of water use were widely divergent. Rates of transpiration per unit land area (Ec) and canopy conductance of E. camaldulensis that was dominant in the clay-zone were about 50% lower than those for E. microcarpa in the same zone. This was in marked contrast to the behavior of trees growing in the sand-zone where water availability was persistently low and variations in sapwood density, sapwood area and canopy conductance were narrow. This resulted in almost identical rates of water use for the two species in the sand-zone, despite E. microcarpa dominating the stand. Contrary to many previous studies, sapwood density was positively correlated with Ec in these eucalypt species, while the proportion of trunk area assigned to sapwood declined with sapwood density. Consequently in this low rainfall environment, with prolonged dry seasons, dense sapwood safeguards against turgor loss, and possibly xylem embolism, thereby allowing Ec to be sustained under extremely low soil-water availability. We concluded that variation in hydraulic traits is less likely where trees are under persistent water-stress than where the stress is short and relatively mild. We developed single functions for predicting Ec for the two species by integrating their responses to micrometeorological and soil-water conditions. © 2010.

Burgess S.S.O.,University of Western Australia | Burgess S.S.O.,Cooperative Research Center for Plant Based Management of Dryland Salinity | Kranz M.L.,University of Western Australia | Kranz M.L.,Cooperative Research Center for Plant Based Management of Dryland Salinity | And 4 more authors.
Agricultural and Forest Meteorology | Year: 2010

Over the past few decades, wireless technologies have revolutionized personal communications by improving flexibility and solving myriad logistical constraints. Recently, wireless sensor technologies have begun offering similar enhancements to communications between the scientist and the environment. This includes monitoring of civil structures and natural ecosystems. Although forest biology has benefited from novel technologies such as remote sensing and GIS, many 'on the ground' sensing technologies have not changed in many decades. What can wireless sensor networks offer the forest and agricultural scientist? We suggest at least three benefits: improved experimental design via flexible equipment deployment, improved monitoring access in logistically challenging environments (i.e. tall tree canopies) and increased density of observations for better validation of models and hypotheses. Here we briefly describe the current state of wireless environmental monitoring from an end-user point of view and report our initial attempts to adapt this cutting-edge technology to the realm of forest research. © 2009 Elsevier B.V. All rights reserved.

Feikema P.M.,University of Melbourne | Feikema P.M.,Cooperative Research Center for Plant Based Management of Dryland Salinity | Feikema P.M.,Cooperative Research Center for Greenhouse Gas Technologies | Baker T.G.,University of Melbourne | Baker T.G.,Cooperative Research Center for Greenhouse Gas Technologies
Agricultural Water Management | Year: 2011

Management of salinity may include establishing trees in saline areas to enhance discharge and may enable productive use of saline land. Field studies of the performance of trees in saline conditions are generally confined to the initial years after planting, and little quantitative data are available on the relationship between the growth rates of eucalypt species to soil salinity in field conditions at later ages (e.g. 10 years). In this study, the growth of irrigated Eucalyptus globulus, E. grandis and E. camaldulensis is examined in relation to soil salinity measured using an electromagnetic induction device (EM38).The EM38 was found to be an effective tool in determining survival and growth responses of three Eucalyptus species to levels of soil salinity. Differences in measured tree survival, stand volume and leaf area index were correlated with soil salinity. Of the three species, E. globulus performed best in terms of survival and volume growth to age 10 years under slight to moderate salinity conditions, while E. camaldulensis performed best under moderate to severe soil salinity. The ranking of these species for salinity tolerance is consistent with pot trials and younger field trials.This study highlighted the high spatial variability associated with soil salinity, and studies relating the growth of trees in the field should best be analysed on an areal or stand basis, thereby accounting for variability of salt stored in the soil, and reducing the influence of inter-tree competition on growth-salinity relationships. These results have implications for site selection and management of eucalypts in saline areas. © 2011 Elsevier B.V.

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