Smarter Irrigation for Profit

1. Many operators are not getting the basics right. Conducting annual system checks including pumps, getting the start-up time right and avoiding the ‘green drought’ increased productivity by 40% on some sites.
2. Variable rate irrigation can achieve productivity gains of 30%.
3. Autonomous irrigation is feasible for dairy and has potential for wider application.

SIP 1 recommended increased water productivity for dairy can be achieved by swiftly adopting a number of cost-effective key fundamentals:

• Maintain the irrigation system to ensure efficient and effective operation. Start with a comprehensive irrigation system performance evaluation and implement recommendations. Use available system check lists to prepare for the coming season as an ongoing measure.
• Use water balance calculation tools to inform irrigation scheduling decisions to apply water at the right time and right rate to maintain soil moisture in the readily available water (RAW) zone of the soil profile.
• Monitor soil moisture using professionally installed soil moisture monitors and reliable telemetry to inform irrigation start-up decisions at the commencement of the season or after rainfall events. This technology provides a measurement of the effectiveness of rainfall and irrigation on rising or maintaining soil moisture to within the RAW zone.
• Know the capacity of the irrigation system and schedule irrigation accordingly to maintain soil moisture requirements whilst deploying cost-effective measures such as the use of off-peak power. Potential for the irrigation system to raise soil moisture to the RAW zone for plant growth can become limited by the system's capacity if soil moisture levels are depleted in that zone.
• Measure to monitor: Ensure usage, cost of energy and water can all be monitored against production outcomes. This means monitoring energy bills, installing a flow-meter and taking pasture measurements.
• Maintaining soil moisture within the RAW zone creates the ideal platform for strategic nitrogen use.

To assist with the aim of improving water productivity, tools and technologies were adopted on all optimisation sites to aid in irrigation decision making. These tools and technologies included:

• Soil moisture monitors were installed. These were capacitance probes, with real-time telemetry and app-accessible reporting to monitor the effect of irrigation and rainfall on soil moisture

• Irrigation system and pump evaluations. Baseline evaluations were compared to evaluations after system changes were implemented. 

• Pasture and crop production was monitored and compared against satellite measurement systems and modelled potential yield. 

• IrriPasture, an online weather-based water balance calculator, was used to assist with irrigation scheduling. It was further developed to include crops such as maize, sorghum and millet as well as lucerne, shallow rooted perennials and annual pastures. 

Across the three years of the project, diverse weather conditions were experienced at all sites.  End of drought to flooding, and all weather conditions in between made it difficult to interpret the improvement in some sites as a result of changed irrigation practices. However, at other sites there is excellent data showing the improvement in water productivity due to the changed irrigation practices.

Gross production water use index (GPWUI)

An average of 50% improvement in the Gross production water use index (GPWUI) was achieved across the ten sites, with the range in the third year from 0.9tDm/ML to 3.03tDm/ML. The GPWUI is a measure of the tonnes of dry matter produced per mega litre of rainfall and irrigation. 

These improvements were made as a result of the following changed practices: 

• Irrigation commenced earlier at the beginning of the irrigation season

• Irrigation commenced on time after rainfall events

• Irrigation application frequency and rate changed to maintain soil moisture in the readily available water zone. 

• Pumps were overhauled or new pumps purchased to increase efficiency

• Sprinkler packages were overhauled or purchased to improve water application uniformity. 

Engagement

Over the period of the 'What’s my yield gap? Improving water productivity project', more than 1700 dairy farmers and service providers attended field days, meetings, workshops and webinars, with industry newsletters, articles, and video's reaching more than 136,000 readers. 

Feedback from the extension activities reported an improvement in knowledge of participants and the high likelihood of participants changing irrigation practices to improve water productivity.

Technology

Some technologies implemented on the optimisation sites were adopted widely by participating farmers. Seventy nine percent of participants surveyed at the completion of the project had started to use evapotranspiration and rainfall forecast to conduct water balance to assist with irrigation decisions. Another twenty one percent were still considering using this information.

Soil moisture probes was another technology that was adopted widely by farmers participating in the SIP2 project. Fifty two per cent of participating farmers started using probes to assist with decision making and another 43 per cent were still considering.

The high level of adoption of irrigation start up time at the beginning of the season and after rainfall and the rates and frequency of irrigation increased productivity, water and energy efficiency.

In conclusion, the SIP2 project increased the adoption of technologies and tools to assist the irrigation decision making of dairy farmers and improved water productivity and energy efficiency on participating farms. Further improvement in the water use and energy efficiency of dairy farmers will be beneficial to farmers and the industry as water availability becomes more volatile and energy prices continue to rise. 

• Mepunga East - WestVic Dairy region  
• Mt Gambier - DairySA 
• Mt Compass – Dairy SA 
• Dardanup – Western Dairy 
• Tongala -Murray Dairy 
• Cobains – GippsDairy  
• Yarram - GippsDairy 
• Bega – Dairy NSW 
• Tocal – Dairy NSW 
• Coraki – SubTropical Dairy