Browsing by Author "Inman-Bamber, NG"

Now showing 1 - 9 of 9

Climate ready sugarcane : traits for adaptation to high CO2 levels
(2014) Stokes, CJ; Inman-Bamber, NG
Recent work in Brazil and Florida had shown strong responses of sugarcane to elevated CO2, even under well-watered conditions. These results were not expected from current understanding of leaf physiology, given that sugarcane is a C4 plant, possessing a photosynthetic pathway that concentrates CO2 and achieves close to optimal rates of carbon fixation even at current low levels of CO2. The results suggested that the mechanisms by which elevated CO2 affects sugarcane may not be fully understood or, at least, that there may be genetic variation in responses. Fully capturing the benefits of rising CO2 could assist the sugarcane industry in adapting to climate change and offsetting potential negative effects associated with rising temperatures and recurring droughts, if they were to become more frequent. The main objectives of this project was therefore to contribute to the sugar industry’s adaption to climate change by conducting experiments to determine the mechanisms by which rising CO2 affects sugarcane, assessing the genetic variation in CO2 responses and the potential these provide for selecting ‘climate-ready’ genotypes for the future, and incorporating these findings into improved modelling approaches to be able to better represent the effects of future CO2-enriched climates on sugarcane crops.
Efficient use of water resources in sugar production: a physiological basis for crop response to water supply
(1999) Inman-Bamber, NG; Robertson, MJ; Muchow, RC; Wood, AW
Although sugar is produced in the some of the most humid regions of Australia, water remains a major limitation to production. Experience in other rainfed and irrigated production systems in Australia has shown that use of both surface and ground water resources can easily have long term impacts on future productivity of the system. There is no reason why the sugar industry should be exempt from the consequences of ignorance or mismanagement in regard to the hydrological cycle. At the outset of this project, it was clear that efficient use of water (both rainfall and irrigation) was central to profitable and sustainable sugarcane production. Maximum profitability in fully-irrigated systems required the application of water to match crop water requirements for cane and sucrose production, as moderated by climate and management inputs. Under supplementary-irrigation, the timing of water application in relation to growth stage and climatic conditions was thought to be critical for maximising the economic benefit from a limited water resource. In rainfed systems, profitability could be maximised, by matching management inputs to the production potential and production risk as determined by rainfall variability in different climates. During the life of this project, there has been increased public awareness of water as a production factor and more importantly as a national resource and major component of a fragile environment. The National Agenda for Water Reform has moved in the direction of full recovery of water supply cost, separate water and property rights, specific water allocation to the environment and increased water use efficiency in agriculture. A new initiative on water use efficiency has been launched by DNR who have asked the sugar industry to make 60,000 MI available for irrigation from existing water resources. The products ofCTA016 are therefore highly pertinent for the current focus on water use in the Australian sugar industry. Radiation and temperature as key sugarcane production factors were the subject of SDRC Projects CTA004 and CTA012. These projects have led to a better understanding of the processes of yield and CCS accumulation under conditions of high water and nutrient inputs. Limits to yield in terms of these climatic factors have been identified. Crop growth mechanisms driven by radiation and temperature have been established and captured in mathematical expressions which were necessary for the development of the Sugarcane module now in use within the APSIM modelling environment. In CTA016, the strategic research approach of the earlier projects was extended to water as production factor. Water has of course been extensively researched in the sugar industry largely from the perspective of irrigation requirements. CTA016 was designed to build on past research by going into more detail in order to improve our knowledge of the soil-plant-atmosphere continuum of water. Knowledge of the mechanisms identified as important have been formalised mathematically and incorporated into the APSIM-Sugarcane modelling environment. This project has thus augmented the output from the earlier projects by adding the water balance and crop response to water stress to modelling capability. This capability was then used extensively in developing practical guidelines for saving water during drying off and during early stages of development. This modelling capability was also tested and used in a later more applied project (CTAOI8) to facilitate more efficient use of limited water supplies under supplementary irrigation.
Efficient use of water resources in sugar production; optimising the use of limited water under supplementary irrigation
(2000) Inman-Bamber, NG; Robertson, MJ; Muchow, RC; Wood, AW; Wegener, MK; Spillman, MF
About 60% of sugar produced in Australia depends on irrigation. In some regions, production would be impossible without irrigation; in others, irrigation is used to supplement rainfall. It can improve production and reduce risks in the more variable rainfall environments. The whole subject of supplementary irrigation has taken on a new focus in recent years as termsof- trade for cane growers continue to deteriorate, and as pressure mounts for more efficient management of a scarce national resource. Best practice with limited water, however, depends on complex biophysical and economic factors as well as sensitive off-site impacts. From a biophysical point of view, questions arise as to the probability of achieving the desired irrigation responses in the various regions and seasons, and the extent to which this is affected by crop water requirements at various stages and by variety and soil type. From a management point of view, the questions concern source of the water, the amounts available, and the best crop type and block on which to apply it. Finally, from an economic point of view, the questions concern the interactions between the above factors and the size of the investment required, the likely price of cane, and the probability of achieving sustained profitability from the investment during its lifetime. The aim of this project, therefore, was to address this complexity by developing and applying a generic methodology for assessing the payoffs of supplementary irrigation, taking account of the above factors.
Implementation of irrigation practices for profitable resource efficient sugarcane production in the Ord : Final report CSE007
(SRDC, 2006) Inman-Bamber, NG
Sugarcane is currently the major crop in the Ord River Irrigation Area (ORIA) in terms of area, occupying approximately 4000 hectares or a third of the irrigable area. It is also possible that further expansion could occur soon within the Ord Stage 2 area. The new industry is continuing to develop guidelines for and to initiate implementation of best management practice, to ensure the development of a profitable and sustainable industry. This project contributed to the provision of an extension service which is critical in assisting the industry in this development. Irrigation water application in excess of 30 ML ha-1 yr-1 was common commercial practice when sugarcane production commenced in 1995. High irrigation application not only impacted on profitability but also contributed to rising water tables and land degradation. Consequently this project aimed to build capacity in the community to save water and labour and to reduce rising water tables.
Increased profitability and water use efficiency through best use of limited water under supplementary irrigation : SRDC Final report CSE001
(SRDC, 2005) Inman-Bamber, NG
The objectives of this project towards increased profitability and water use efficiency was to:
Irrigation risk management strategies to reduce water use and maximize profitability; a paradigm shift in performance to $ per unit of water : Final report CTA038
(SRDC, 2003) Inman-Bamber, NG
The Australian sugar industry is predisposed to maximize the benefits of irrigation because of its geographic and climatic location. However mistakes of older irrigation schemes elsewhere in Australia, need to be avoided. Performance criteria such as $ produced per unit of water used 'which have the long term aim of very closely matching plant water use with water applied, will be the single most important factor ensuring longevity of irrigation areas' (Meyer, 1997). Matching plant water use and irrigation, requires knowledge of climatic demand for water, soil water supply, and crop response to water deficits.
Knowledge of sugarcane physiology and climate-crop-soil interactions : SRDC final report
(2003) Inman-Bamber, NG
Compared to other crops, knowledge of growth mechanisms in sugarcane is inadequate. The question arises as to how much longer can we continue to prosper from sugarcane if knowledge of the growth processes on which our industry depends, remains outdated? Sucrose accumulation and efficient use of resources are primary concerns for this industry. To date we have only limited understanding of climate and management links to sucrose content or CCS and this undermines our ability to manage water, nutrients, varieties and the harvest schedule for maximum CCS and optimum cane yield. Cane and sucrose yields are often below potential for reasons about which we can only speculate (Leslie and Byth, 2000). In the past, research funds have been directed at opportunities for raising limitations to yield and efficiency of resource use at the gene and enzyme level as well as at the crop and paddock level. There has been no attempt to integrate research or information across these disciplines or to assess where progress toward sustainable production is most likely to be achieved. SRDC recognized that it was now time for each discipline interested in the same processes to get together to find out how their different approaches could be complementary. SRDC also recognised the need to review past data relating to crop growth in the later stages of crop development to see if something could be done about under performing crops during this stage.
Pathways to exploiting enhanced photosynthetic efficiency for higher sucrose and biomass yield
(2011) Inman-Bamber, NG
Australia has one of the highest commercial cane sugar (CCS) levels in the world but unfortunately CCS appears to have plateaud at about 14% of fresh cane weight over the past 20 years. Up to now in breeding programs, increased fibre has been considered to have negative economic impacts because of adverse effects on sugar extraction and milling rate. It is possible that high fibre genotypes can produce higher biomass yields than high sucrose types because high sucrose content in the stalk may feedback negatively on photosynthesis either through end-product suppression or through sugar signalling compounds. This is now an assumption which is gaining acceptance through recent publications. Prior to this project this assumption had not been tested using high fibre and high sucrose clones. Feedback inhibition is also suspected to be the cause of the ‘reduced growth phenomenon’, a term applied to lower than expected biomass accumulation after a certain stage in crop development. This project aimed to establish the role of cane stalk sucrose in feedback inhibition of photosynthesis in order to reveal existing limitations to increasing sucrose content and biomass yield.
SRDC Research Project final report Increased CCS, cane yield and water use efficiency by exploiting interactions between genetics and management
(2009) Inman-Bamber, NG
In October 2003 delegates at an international workshop on sugarcane physiology funded by SRDC concluded that priority should be directed at a better understanding of traits responsible for high yield and high sucrose content, in order to better design future genotypes. While pathways of sucrose accumulation were and are being investigated at the molecular and cellular levels, there was no concurrent work at the crop level. Consequently it is difficult to answer the questions- To what extent will genetic improvements be modified by management and the environment? and conversely, To what extent does management and environment influence the selection of varieties? These and other questions about the genotype x environment (GxE) interaction on sucrose accumulation and lodging were the major concerns of this project with sucrose accumulation as the predominant issue. This project forms part of a large effort now underway worldwide to find alternative methods to develop cultivars with improved sugar content. The main objective was to better understand the interactions between sugarcane genetics and the environment (including management) with respect to sugar accumulation. After four years of intensive work the project has delivered extensive new knowledge on the physiology of interactions between sugarcane genetics and the environment with respect to sugar accumulation and lodging and as such has met the main objective of the research.