Browsing by Author "Reghenzani, J"

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Final report on SRDC project CLW002 (previously CSS02 & CSS2S): The role of root growth and activity in determining sugarcane productivity
(1999) Magarey, RC; Nable, R; Reghenzani, J; Smith, J; Berthelsen, S; Grace, D; Robertson, M
When the current project was initiated, poor root growth and activity were widely believed to be a major constraint to sugarcane productivity. However, there was no technology available to assess whether or not root growth and activity were constraining cane productivity. The project was established to examine the relationship between root growth and activity and sugarcane productivity. The strategic information to be generated was expected to provide the basis for estimating the potential value of overcoming poor root growth and/or activity by managing various soil constratints such as soil pathogens, poor soil structure, or low soil fertility. Initially, the objectives of CLW002 were to: quantify the relationship between root system characteristics and crop productivity; assess the methods for measuring root activity as indicators of root system constraints on crop productivity - with particular emphasis on methods that would allow remote assessment of root activity.
Quantifying and managing sources of sediments and nutrients in low-lying canelands : Project no CLW007 - final report
(2003) Roth, CH; Visser, F; Wasson, R; Reghenzani, J; Prosser, I
Queensland’s north-east coast are used for sugar production. Various studies investigating sediment discharge from catchments where sugar is an important land use have demonstrated that sediment export from cane lands often continues to be higher than from adjacent forested areas or other land uses. The main concern with the export of sediments is the loss of associated nutrients, in particular forms of phosphorus and nitrogen bound to the fine sediment fractions (suspended sediments), and the potential harm these materials might cause in rivers, wetlands and near shore marine ecosystems. Many growers are aware of these issues and have proactively engaged in a variety of activities and practices to reduce the likelihood of such environmental impacts, and the widespread adoption of trash blanket harvesting is testimony to this. However, there is still a lack of understanding on the exact amounts and sources of sediments and nutrients leaving cane lands. More importantly, growers lack information on practical solutions to reducing sediment export and where to target the most appropriate sediment control measures. In response, SRDC funded Project CLW007 with the aim to develop a robust understanding of sediment sources, transport pathways and sinks as the means to better target cane land management towards reducing sediment export. The approach chosen was to develop a sediment budget for representative areas of low-lying cane lands in the Herbert district. This approach has particular advantages for resource management purposes as it ensures that all components in a catchment sediment transport system are examined, so that important sediment sources and transport processes can be identified and management appropriately targeted. The bulk of the study was conducted in a 536 ha large subcatchment of Ripple Creek in the Lower Herbert, comprising 320 ha of low-lying floodplain soils under sugar and 216 ha of forested uplands. A range of monitoring methods were developed and implemented in order to capture the breadth of processes and to employ the most appropriate methods in each individual situation and best suited to each scale of measurement
The role of root growth and activity in determining sugarcane productivity : SRDC final report CLW002 (previously CSS02 & CSS2S)
(1999) Magarey, R; Nable, R; Reghenzani, J; Smith, J; Berthelsen, S; Grace, D; Robertson, M
Research conducted in this project aimed to better understand the relationship between root and shoot growth, in areas such as how the size of the root system affects shoot growth, do particular root parameters have a controlling influence on shoot growth, how do soil characteristics affect root penetration rates, and how the root system develops through the life of a sugarcane crop. This was achieved through the application of a wide range of experimental techniques in both the glasshouse and field situation. The study of root systems in sugarcane is difficult - due to the size of the crop and the length of the cropping period. As a result there have been few previous studies on sugarcane root systems in Australia, and indeed around the world. A number of techniques were either developed, or adapted, in this project research. A soilless aeroponic culture technique was installed and refined at Tully Sugar Experiment Station. This allowed sugarcane roots to be examined on a daily basis and root measurements made, or root pruning to occur. This overcame the difficulty of dealing with the bulky, opaque soil medium. A tall pot system was adapted for sugarcane where sugarcane could be grown for an extended period in controlled conditions. This enabled plant water relations to be studied in association with modification to root growing conditions. Root image analysis techniques were further refined for sugarcane, allowing measurement of both whole glasshouse-grown root systems, or the quantification of root lengths in material from soil cores obtained in the field. A technique for growing sugarcane with a split root system was also adapted enabling the direct and indirect effects of water stress and root pruning in a soil culture to be examined, and the likely presence of root signals as a mechanism for control of shoot growth. Studies using these techniques facilitated an examination of the relationship between roots and shoots under various experimental conditions - ranging from controlled conditions with no soil in the glasshouse, through other soil-based glasshouse trials, to the field situation. This gave depth to project results and a broader understanding of root-shoot relationships using a range of experimental observations.