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Papers by Sam North

Irrigation Australia: The Official Journal of Irrigation Australia, 2013

... Particularly Michael McBurnie, Deniliquin, for his time and patience during our chats down th... more ... Particularly Michael McBurnie, Deniliquin, for his time and patience during our chats down the paddock ... properties to collect our data. Co-operators in the Murrumbidgee valley: Tim and Roger Commins, Ian Blight and Ian Sutherland ...

The cost of irrigation water accounts for 20-30% of the total variable costs of rice production i... more The cost of irrigation water accounts for 20-30% of the total variable costs of rice production in the Murrumbidgee and Murray Valleys. Rice production consumes a substantial proportion of the available supply of irrigation water. Any agronomic/water management practice that has the potential to reduce water use should be investigated. Research in the Burdekin River Irrigation Area indicated that crop water use of rice grown on raised beds was 32% less than when grown using conventional permanent flood. Whilst recognising that there are likely to be agronomic constraints to rice production on raised beds in the Riverina, investigations into potential water savings, were investigated in this project. The project evaluated the water use efficiency of rice grown on a raised bed layout on two of the principal soil types used for rice production (four experiments). This layout was compared with the now traditional aerial sown fully ponded flat layout. The opportunity to explore water management options on the raised bed layout was also undertaken in three of the experiments. Water use was quantified and agronomic performance of the rice crop monitored. Maintaining water in the furrows all season reduced grain yield by an average of 10% (range 7-20). In three of the four experiments harvest index was lower where water was maintained only in the furrows. Moisture stress during panicle development and grain filling may have contributed to this result. Although sterility was not measured, no affected panicles were observed. Water use, where water was maintained in the furrows, was reduced by 14% (range 7-18). Water use efficiency increased on two occasions but decreased on one. Efficiencies for the two irrigation layouts by water management treatments of most interest (water maintained in the furrows; fully ponded flat) ranged only from 7.1 to 8.1 kg/ha/mm of water used by the crop. Despite an apparently similar soil type across the experimental areas, considerable variation in water use between plots with the same water management was measured. When attempting to measure water use in 'small plots' it is recommended that there be a minimum of four replications and/ or differences in water management between treatments be substantial. This project demonstrated that rice can be successfully grown on the raised bed layout (yields > 10 t/ha). Reductions in water use will not be as substantial as those reported from Queensland. Where water 'subs' readily to the centre of the raised bed grain yield, water use and water use efficiency are all likely to be similar to the traditional fully ponded flat layout.

The effect of different bay layouts (beds vs flat) on crop growth was investigated using continuo... more The effect of different bay layouts (beds vs flat) on crop growth was investigated using continuous monitoring of redox potentials to explain soil O2 and nutrient (N and P) availability. Paddy rice typically leaves the soil in an anaerobic and water-logged state with low or negative redox potential. These conditions transform nutrients in the soil: free nitrate is reduced to di-nitrogen gas, and iron, phosphorous and manganese are reduced to their soluble forms. Following drainage of bays for rice harvest, re-oxidation of the soil causes other transformations, such as phosphorous and iron precipitation. These may negatively affect cereal crops planted straight after rice harvest. Raised beds may provide better soil conditions for crops after rice, making double cropping more viable and lifting the total water productivity of Australian rice farming systems. A wireless measurement and data logging system was developed and used to monitor redox potentials continuously. Very high input...

Acknowledgment The National Program for Sustainable Irrigation focuses research on the developmen... more Acknowledgment The National Program for Sustainable Irrigation focuses research on the development and adoption of sustainable irrigation practices in Australian agriculture. The aim is to address critical emerging environmental management issues, while generating long-term economic and social benefits that ensure irrigation has a viable future. The Program has fourteen funding partners who are: Land & Water Australia (Managing Partner);

Surface irrigation systems are generally designed using engineering or operational criteria and t... more Surface irrigation systems are generally designed using engineering or operational criteria and these may not reflect best agronomic practice. In particular, long intake opportunity times (i.e. the time water is ponded above the soil surface during an irrigation) on heavy textured soils can lead to waterlogging and yield loss, so maximum opportunity times are recommended. However, recommended maximum opportunity times for surface irrigation systems in southern NSW are not based on experimental data and they vary widely (8 to 15 hours). Furthermore, there is evidence they might differ with soil type. To examine these two questions, pot and field trials were conducted using a representative crop (wheat) between 2008 and 2010 on soils typical of surface irrigated systems in southern NSW. It was shown there was: • a strong correlation between wheat growth at anthesis and redox potential (E h) when E h dropped below the oxygen limiting threshold of 350 mV. • an explicable relationship be...

CRC for Irrigation Futures Irrigation Matters …, 2008

The Cooperative Research Centre for Irrigation Futures advises that the information contained in ... more The Cooperative Research Centre for Irrigation Futures advises that the information contained in this publication comprises general statements based on scientific research. The reader is advised and needs to be aware that such information may be incomplete or unable to be used in any specific situation. No reliance or actions must therefore be made on that information without seeking prior expert professional, scientific and technical advice. To the extent permitted by law, the Cooperative Research Centre for Irrigation Futures (including its employees and consultants) excludes all liability to any person for any consequences, including but not limited to all losses, damages, costs, expenses and any other compensation, arising directly or indirectly from using this publication (in part or in whole) and any information or material contained in it. This work has tried to shed some light on our current understanding of these designs and where we need to invest research effort. The first report looks at the current practices. The second report looks at the research needs to evaluate current layouts and provide appropriate designs. We hope that this review material will be useful to anyone seeking to understand this type of irrigation system and promote much needed research into this area.

The cost of irrigation water accounts for 20-30% of the total variable costs of rice production i... more The cost of irrigation water accounts for 20-30% of the total variable costs of rice production in the Murrumbidgee and Murray Valleys. Rice production consumes a substantial proportion of the available supply of irrigation water. Any agronomic/water management practice that has the potential to reduce water use should be investigated.

provided invaluable assistance by allowing us to evaluate their farm systems. The information gat... more provided invaluable assistance by allowing us to evaluate their farm systems. The information gathered from their farms, together with CRC for Irrigation Futures iii their advice and comments, provided the basis for a number of the recommendations in this manual.

The cost of irrigation water accounts for 20-30% of the total variable costs of rice production i... more The cost of irrigation water accounts for 20-30% of the total variable costs of rice production in the Murrumbidgee and Murray Valleys. Rice production consumes a substantial proportion of the available supply of irrigation water. Any agronomic/water management practice that has the potential to reduce water use should be investigated. Research in the Burdekin River Irrigation Area indicated that crop water use of rice grown on raised beds was 32% less than when grown using conventional permanent flood. Whilst recognising that there are likely to be agronomic constraints to rice production on raised beds in the Riverina, investigations into potential water savings, were investigated in this project. The project evaluated the water use efficiency of rice grown on a raised bed layout on two of the principal soil types used for rice production (four experiments). This layout was compared with the now traditional aerial sown fully ponded flat layout. The opportunity to explore water man...

International Journal of Petroleum Technology, 2015

Irrigation Australia: The Official Journal of Irrigation Australia, 2013

... Particularly Michael McBurnie, Deniliquin, for his time and patience during our chats down th... more ... Particularly Michael McBurnie, Deniliquin, for his time and patience during our chats down the paddock ... properties to collect our data. Co-operators in the Murrumbidgee valley: Tim and Roger Commins, Ian Blight and Ian Sutherland ...

The cost of irrigation water accounts for 20-30% of the total variable costs of rice production i... more The cost of irrigation water accounts for 20-30% of the total variable costs of rice production in the Murrumbidgee and Murray Valleys. Rice production consumes a substantial proportion of the available supply of irrigation water. Any agronomic/water management practice that has the potential to reduce water use should be investigated. Research in the Burdekin River Irrigation Area indicated that crop water use of rice grown on raised beds was 32% less than when grown using conventional permanent flood. Whilst recognising that there are likely to be agronomic constraints to rice production on raised beds in the Riverina, investigations into potential water savings, were investigated in this project. The project evaluated the water use efficiency of rice grown on a raised bed layout on two of the principal soil types used for rice production (four experiments). This layout was compared with the now traditional aerial sown fully ponded flat layout. The opportunity to explore water management options on the raised bed layout was also undertaken in three of the experiments. Water use was quantified and agronomic performance of the rice crop monitored. Maintaining water in the furrows all season reduced grain yield by an average of 10% (range 7-20). In three of the four experiments harvest index was lower where water was maintained only in the furrows. Moisture stress during panicle development and grain filling may have contributed to this result. Although sterility was not measured, no affected panicles were observed. Water use, where water was maintained in the furrows, was reduced by 14% (range 7-18). Water use efficiency increased on two occasions but decreased on one. Efficiencies for the two irrigation layouts by water management treatments of most interest (water maintained in the furrows; fully ponded flat) ranged only from 7.1 to 8.1 kg/ha/mm of water used by the crop. Despite an apparently similar soil type across the experimental areas, considerable variation in water use between plots with the same water management was measured. When attempting to measure water use in 'small plots' it is recommended that there be a minimum of four replications and/ or differences in water management between treatments be substantial. This project demonstrated that rice can be successfully grown on the raised bed layout (yields > 10 t/ha). Reductions in water use will not be as substantial as those reported from Queensland. Where water 'subs' readily to the centre of the raised bed grain yield, water use and water use efficiency are all likely to be similar to the traditional fully ponded flat layout.

The effect of different bay layouts (beds vs flat) on crop growth was investigated using continuo... more The effect of different bay layouts (beds vs flat) on crop growth was investigated using continuous monitoring of redox potentials to explain soil O2 and nutrient (N and P) availability. Paddy rice typically leaves the soil in an anaerobic and water-logged state with low or negative redox potential. These conditions transform nutrients in the soil: free nitrate is reduced to di-nitrogen gas, and iron, phosphorous and manganese are reduced to their soluble forms. Following drainage of bays for rice harvest, re-oxidation of the soil causes other transformations, such as phosphorous and iron precipitation. These may negatively affect cereal crops planted straight after rice harvest. Raised beds may provide better soil conditions for crops after rice, making double cropping more viable and lifting the total water productivity of Australian rice farming systems. A wireless measurement and data logging system was developed and used to monitor redox potentials continuously. Very high input...

Acknowledgment The National Program for Sustainable Irrigation focuses research on the developmen... more Acknowledgment The National Program for Sustainable Irrigation focuses research on the development and adoption of sustainable irrigation practices in Australian agriculture. The aim is to address critical emerging environmental management issues, while generating long-term economic and social benefits that ensure irrigation has a viable future. The Program has fourteen funding partners who are: Land & Water Australia (Managing Partner);

Surface irrigation systems are generally designed using engineering or operational criteria and t... more Surface irrigation systems are generally designed using engineering or operational criteria and these may not reflect best agronomic practice. In particular, long intake opportunity times (i.e. the time water is ponded above the soil surface during an irrigation) on heavy textured soils can lead to waterlogging and yield loss, so maximum opportunity times are recommended. However, recommended maximum opportunity times for surface irrigation systems in southern NSW are not based on experimental data and they vary widely (8 to 15 hours). Furthermore, there is evidence they might differ with soil type. To examine these two questions, pot and field trials were conducted using a representative crop (wheat) between 2008 and 2010 on soils typical of surface irrigated systems in southern NSW. It was shown there was: • a strong correlation between wheat growth at anthesis and redox potential (E h) when E h dropped below the oxygen limiting threshold of 350 mV. • an explicable relationship be...

CRC for Irrigation Futures Irrigation Matters …, 2008

The Cooperative Research Centre for Irrigation Futures advises that the information contained in ... more The Cooperative Research Centre for Irrigation Futures advises that the information contained in this publication comprises general statements based on scientific research. The reader is advised and needs to be aware that such information may be incomplete or unable to be used in any specific situation. No reliance or actions must therefore be made on that information without seeking prior expert professional, scientific and technical advice. To the extent permitted by law, the Cooperative Research Centre for Irrigation Futures (including its employees and consultants) excludes all liability to any person for any consequences, including but not limited to all losses, damages, costs, expenses and any other compensation, arising directly or indirectly from using this publication (in part or in whole) and any information or material contained in it. This work has tried to shed some light on our current understanding of these designs and where we need to invest research effort. The first report looks at the current practices. The second report looks at the research needs to evaluate current layouts and provide appropriate designs. We hope that this review material will be useful to anyone seeking to understand this type of irrigation system and promote much needed research into this area.

The cost of irrigation water accounts for 20-30% of the total variable costs of rice production i... more The cost of irrigation water accounts for 20-30% of the total variable costs of rice production in the Murrumbidgee and Murray Valleys. Rice production consumes a substantial proportion of the available supply of irrigation water. Any agronomic/water management practice that has the potential to reduce water use should be investigated.

provided invaluable assistance by allowing us to evaluate their farm systems. The information gat... more provided invaluable assistance by allowing us to evaluate their farm systems. The information gathered from their farms, together with CRC for Irrigation Futures iii their advice and comments, provided the basis for a number of the recommendations in this manual.

The cost of irrigation water accounts for 20-30% of the total variable costs of rice production i... more The cost of irrigation water accounts for 20-30% of the total variable costs of rice production in the Murrumbidgee and Murray Valleys. Rice production consumes a substantial proportion of the available supply of irrigation water. Any agronomic/water management practice that has the potential to reduce water use should be investigated. Research in the Burdekin River Irrigation Area indicated that crop water use of rice grown on raised beds was 32% less than when grown using conventional permanent flood. Whilst recognising that there are likely to be agronomic constraints to rice production on raised beds in the Riverina, investigations into potential water savings, were investigated in this project. The project evaluated the water use efficiency of rice grown on a raised bed layout on two of the principal soil types used for rice production (four experiments). This layout was compared with the now traditional aerial sown fully ponded flat layout. The opportunity to explore water man...

International Journal of Petroleum Technology, 2015