Armidale, Australia
Armidale, Australia

Time filter

Source Type

Dixon M.,Environment Canada | Graham T.,Environment Canada | Bam P.,Environment Canada | Kervin J.,Environment Canada | And 4 more authors.
Acta Horticulturae | Year: 2015

High mortality rates among most species of nursery trees after transplanting is generally attributed to water stress imposed by a range of soil and other environmental conditions. This study examined the efficacy of a consortium of mycorrhizae (Root Rescue Landscape Powder), comprised of 20 species of both endo-And ecto-mycorrhizae, in mitigating water stress when inoculated into the root zone of recently transplanted trees [Thuja occidentalis 'Smaragd' (emerald pyramidal cedar) and Acer rubrum 'Brandywine' (Brandywine red maple)]. The water status of the trees was monitored with automated stem psychrometers measuring stem water potential () at 30-min intervals for at least 2 weeks after transplanting. Treated trees exhibited a significant reduction in mid-day water stress and enhancement of overnight rehydration, relative to control trees, when inoculated with the consortium of mycorrhizae, as shown by diurnal patterns of water stress and recovery.


Tran N.,Environment Canada | Bam P.,Environment Canada | Black K.,Environment Canada | Graham T.,Environment Canada | And 4 more authors.
Acta Horticulturae | Year: 2015

Conventional irrigation practices are based on physical factors and observations, however this fails to include plant water status measurements. This study examined the relationship between cumulative water potential with concurrent cumulative vapour pressure deficit (VPD) for the common nursery species Thuja occidentalis 'Smaragd' (emerald pyramidal cedar). Establishing the relationship for these plantenvironment interactions will provide nursery growers with a rational irrigation scheduling tool that indicates a more effective and efficient use of scarce water resources. Plant water status and environmental conditions were monitored throughout a growing season taking measurements every 15 min between irrigation events. The overall relationship between cumulative water potential and cumulative VPD exhibited a slope response of-2.2 MPah/kPah. This coefficient provides growers with an objective tool for irrigation management for this species and leads the way to exploit this approach across the spectrum of nursery commodities.


Nadezhdina N.,Mendel University in Brno | Cermak J.,Mendel University in Brno | Downey A.,ICT International Pty Ltd | Downey A.,University of Western Australia | And 6 more authors.
Journal of Hydrology and Hydromechanics | Year: 2015

Symmetrical temperature difference also known as the sap flow index (SFI) forms the basis of the Heat Field Deformation sap flow measurement and is simultaneously collected whilst measuring the sap flow. SFI can also be measured by any sap flow method applying internal continuous heating through the additional installation of an axial differential thermocouple equidistantly around a heater. In earlier research on apple trees SFI was found to be an informative parameter for tree physiological studies, namely for assessing the contribution of stem water storage to daily transpiration. The studies presented in this work are based on the comparative monitoring of SFI and diameter in stems of different species (Pseudotsuga menziesii, Picea omorika, Pinus sylvestris) and tree sizes. The ability of SFI to follow the patterns of daily stem water storage use was empirically confirmed by our data. Additionally, as the HFD multipointsensors can measure sap flow at several stem sapwood depths, their use allowed to analyze the use of stored water in different xylem layers through SFI records. Radial and circumferential monitoringof SFI on large cork oak trees provided insight into the relative magnitude and timing of the contribution of water stored in different sapwood layers or stem sectors to transpiration. © 2015 2015.


Forster M.A.,ICT International Pty Ltd
Fungal Ecology | Year: 2012

Fungal rust galls are parasitic fungi on Acacia host plants. The amount of water required by fungal parasites has yet to be widely measured. Sap flow instrumentation was installed on branches of Acacia implexa to measure water use of a fungal rust gall. Host water use was also measured. Partial regression analysis, using gall sap flow against environmental variables, was performed to determine a possible driving mechanism of gall sap flow. Following the removal of galls from branches, sap flow immediately returned to, and stayed at, zero flow. Gall sap flow was 4.63 % of total host tree sap flow on a daily and cumulative basis. Vapour pressure deficit explained the greatest amount of variation in gall sap flow, suggesting gradients of water potential was the driving mechanism of water use. This study demonstrated that instruments which can measure low sap flow can be used to quantify fungal water use. © 2012 Elsevier Ltd and The British Mycological Society.

Loading ICT International Pty Ltd collaborators
Loading ICT International Pty Ltd collaborators