New project answering key questions for northern Victorian irrigators

By Dairy News Australia

Increasing yield and optimising input efficiencies with irrigation is the focus of a nationwide maximising water productivity project titled Smarter Irrigation for Profit Phase 2 (SIP2).

Tongala dairy farmers Andrew Tyler and son James are part of the three-year project managed by Murray Dairy which commenced in late 2019.

The 2019-20 year of the project was used as an opportunity to collect baseline data on yield and water use, track irrigation decisions and learn more about the irrigation system on the Tongala site.

The second phase aims to explore the effectiveness of adopting simple principles to optimise yield and decrease costly inputs while exploring the potential of readily accessible technologies and online decision support tools to better forecast and plan irrigations to drive production.

Murray Dairy site co-ordinator Lisa Menhenett said the research reflected local needs.

“In northern Victoria, many irrigation systems are moving to annual rye-grass, cereals and summer cropping for silage. The site in northern Victoria is looking specifically at a surface irrigated double cropping scenario with maize followed by a winter cereal. We hope to address the lack of regional information on these scenarios,” Ms Menhenett said.

Murray Dairy has also established a pivot irrigation site at the Kyabram dairy farm of Andrew Murphy with the same cropping rotation; both sites will apply the same soil moisture, yield, water and efficiency measurement methods.

Phase 2 will explore the following key questions for local irrigators:

● What is the impact of double cropping on a flood irrigated system and what are the management options to maximise yields in this situation?

● What is the required water for maximum yield of maize under a flood irrigated system followed by an annual crop?

● Is there a benefit to either crop in a double cropping system?

● What is the benefit to yield and quality by applying ‘the last irrigation’? In some cases maximum yield may be compromised if an irrigator does not irrigate the crop to the end. The decision to not apply the last irrigation is often influenced by running out of water, cutting crop for autumn start-up and/or extreme heat conditions.

● What is the quality of maize at various points of growth and what impact does water availability have on quality?

● What are the benefits of using IrriSAT — a free online platform using satellite imagery to determine plant water requirements of crops and forecast irrigation scheduling by integrating local forecast weather information — in monitoring the crop water requirements in conjunction with ETo and soil moisture probes?

Modelling has been undertaken by the Tasmanian Institute of Agriculture to determine potential maize yields with consideration of site soil characteristics, climatic conditions and irrigation, and nutrient/nitrogen inputs. Ongoing annual yield measurements will be compared against this to determine whether changes made to irrigation practices through the project have made a mark on closing the gap between potential and actual yield.

Following the maize crop, the site will be sown to an annual, rye-grass or cereal, also to be modelled and monitored in a similar manner.

“We are working with partner agronomists from Advanced Ag, Stephen O’Connor and Luke Nagle, to ensure we are applying best practices for growing the maize crop and monitoring growth rates by taking dry matter samples throughout the growing season. At the same time, leaf tissue tests will monitor quality with the aim of obtaining an indication of quality at various growth stages — useful if crops are not able to be irrigated through to the ideal end point,” Ms Menhenett said.

Two Enviro-Pro capacitance probes, connected to a Wildeye logger and telemetry unit, will be installed to monitor the effectiveness of rainfall and irrigation in real-time from a smart phone.

The soil moisture monitoring and IrriSAT information provide a wealth of information to Andrew and James Tyler.

A website to chart the progress of the SIP2 project is in development with the aim of weekly updates along with field days to be held across the life of the project.

SIP2 is a collaboration between the dairy, cotton, rice, grains and sugar industries and is supported by funding from the Federal Department of Agriculture, Water and the Environment's Rural R&D for Profit program and Dairy Australia.