CottonInfo field demonstration trial: Optimisation of Application in Tailwater backup system

The project CSD2201, optimised application in a tailwater backup system trial run during the 2021-22 season demonstrated that irrigation performance could be optimised in the first half of the field where the tailwater was not backing up. The water use efficiency was also measured with a Gross Production Water Use Index (GPWUI) of 1.4b/ML.  However, growers still have the problem in a bankless design of knowing when to shut-off the in-flow gates on a bay and open them into the next bay.  From the outcomes of the 2021-22 trial there are two overarching objectives for the 2022-23 trial: 1)      Grower objective: Develop a single sensor to indicate when to stop irrigating a bay to optimise the performance of the system. 2)      Research objective: Further improve SISCO (irrigation performance model) with the collection of more field data. The specific objectives include: 1.       Investigate optimal time to stop inflow into bays and maximise WUE in field. 2.       Measure Irrigation Water Use Efficiency and Gross Production Water Use Efficiency 3.       Measure water infiltration rate, depth and where possible recession from head ditch to tail drain in the siphon-less tailwater backup design to inform SISCO model where tailwater backs up into field. 4.       Estimate application and distribution uniformity in the first half of the field under tailwater backup siphon-less design. 5.       Investigate potential to apply surface irrigation optimisation technologies such as SISCO to the tailwater backup siphon-less design.