Furrow irrigation is commonly used in the Lower Burdekin . While furrow irrigation typically has low pumping , labour and infrastructure costs and technical requirements , irrigation efficiency can vary quite significantly under furrow systems with potential for deep drainage losses and surface run-off . This has been the case in the Lower Burdekin where historical furrow irrigation methods characterised by long furrow lengths and long irrigation periods has resulted in more water being applied to crops than is required , leading to excess groundwater recharge via deep drainage . It is unlikely that the current B class efficiencies could be realised using conventional furrow irrigation across the Lower Burdekin ( Attard , 2014 ; Raine and Bakker , 1996 ) and only methods such as well-designed and well-managed automated furrow irrigation systems and well-designed drip or overhead low pressure irrigation systems are likely to be able to deliver the low risk application efficiencies across the entire irrigated sugarcane area ( Bakker et al ., 1997 ; Alluvium , 2016 ).
Farm size and layout has a major influence on the practical options available for irrigation system changes and / or upgrades . Converting from furrow to drip is relatively simple from a design perspective , since drip can be easily designed to match the shape of any field . As such , 100 per cent of the furrow irrigated area can be converted to drip . Overhead low pressure ( OHLP ) irrigation systems are unlikely to fit neatly into existing farm boundaries , particularly those found in the Delta area given their smaller farm areas and less uniform shapes . These farms would require at least two different irrigation systems , e . g . centre pivot + drip , to service all the productive land under irrigation . In many instances , re-drawing of farm boundaries to better accommodate the OHLP irrigation system would be an advantage and somewhat simplify the design process .
Moving furrow irrigation from conventional to automated , is a simpler process that builds upon the existing infrastructure and skills sets of farmers and associated support services . However , there will still be a need to examine the appropriate design , i . e . inflows and furrow lengths . Automation , if set up correctly , will deliver benefit to existing conventional furrow installations , however the potential will not be realized unless the key parameters are optimized . The costs associated with upgrading existing furrow to automated ( approximately $ 400 to $ 1500 / ha ) will be considerably lower than for conversion to either OHLP or drip .
A farm irrigation design would be essential prior to any upgrades or system changes .
An important factor to consider is the available resources and skills to conduct and manage such changes . These resources and skills are required at all levels of the process from 1 ) the initial irrigation design , 2 ) the installation of the system , 3 ) irrigation agronomy support , and 4 ) the skill set of the farmer to use and correctly maintain the irrigation system . The impact of poor management , or mistakes , can be greater with sub-surface drip than with OHLP or automated furrow . For example , blocked emitters resulting from a fertigation error may lead to yield impacting water stress if the blockage is not detected and then treated ; in a worst-case scenario the tape may need to be replaced .
For the purpose of assessing the costs of achieving best management practice in irrigation management in the Lower Burdekin , Alluvium ( 2016 ) described three main methods of irrigation for the Lower Burdekin which are also referred to here :
1 . |
Well-designed and managed conventional furrow systems ; |
2 . |
Well-designed and managed automated furrow systems ; and |
3 . |
Well-designed and managed drip and overhead low-pressure systems . |
Well designed and managed conventional furrow systems are likely to be most effective in the BRIA where there are lower infiltration soils therefore , less loss to deep drainage during irrigation events . Automated furrow systems typically require more costs to acquire instrumentation for automation and scheduling ( capital ) but there may be greater labour , energy and water savings in the longer term ; a higher level of skill is required than in conventional furrow systems . The use of telemetry and automation enables irrigators to monitor their irrigation systems and maintain continuous management over irrigation events . Telemetry allows growers to communicate with their irrigation systems remotely , while automation enables them to control particular operations such as opening and closing valves and stopping pumps . Additionally , growers are able to monitor field status , which improves their ability to make decisions in real time ( DAF , 2016 ).
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