Water and fertiliser use efficiency improvement
The VegNET Western Australian Strategy is a roadmap for enhancing the state’s vegetable growing businesses. As part of this strategy, VegNET – WA Regional Development Officers (RDOs) will work closely with growers and stakeholders to create value by translating innovation into adoptable field practices. Truyen Vo reports.
As part of this project, VegNET – Western Australia Regional Development Officers (RDOs) Sam Grubiša and Truyen Vo are looking at enhancing the efficiency of fertiliser by integrating soil moisture monitoring, with knowledge on rootzone concept and soil characteristics to fine-tune the irrigation schedule.
The desired outcomes for this project are:
- Develop a strong task force to combine diverse resources and knowledge in irrigation technology.
- Implement a five-stage extension process to enhance growers’ decision-making and innovation adoption.
The five stages of this extension process include:
- Knowledge: Introduce innovation to growers and help them understand the benefits.
- Persuasion: Development of a favourable attitude to the innovation being introduced.
- Decision: Gaining a commitment from growers to adopt the innovation.
- Implementation: Growers putting the innovation into use via a trial-and-error process.
- Confirmation: Reinforcement that the adoption yielded positive outcomes.
Developing a strong task force
The careful implementation of a stakeholder engagement plan has marked the first success step for this project and led to the formation of a strong taskforce in January 2021.
Members of the taskforce share common interests and are committed to contributing resources and knowledge in order to create value by translating new innovation into adoptable field practices.
This taskforce includes experts and scientists from the Western Australian Department of Primary Industry and Rural Development (DPIRD), Perth Natural Resources Management (Perth NRM), Irrigation Australia, Wildeye Soil Moisture Monitoring and VegNET WA RDOs.
Since January 2021, the taskforce has been working together to design field trials and demonstrations and setting them up at two grower properties in Wanneroo.
Implementing field extension services
The plan to implement field trials that demonstrated the benefits of using soil monitoring technology – compared to conventional irrigation techniques growers normally use – was scheduled for February.
Unfortunately, this was delayed due to a COVID-19 lockdown and restrictions that prevented organising the grower meetings and field day events.
In April, the team was finally able to establish the first two field demonstrations.
![](https://ausveg.com.au/app/uploads/2021/08/Rootzone-225x300.jpg)
The field demonstration sites include soil moisture monitoring probes installed at various depths to monitor the soil moisture profile over time, as well as introducing the rootzone concept and soil characteristics to growers.
The participating growers were assisted with downloading an app to their smartphones that allow them to read the soil moisture monitoring results, and better understand the data outputs presented in graph form.
The growers were also presented with field observations of the rootzone and the soil texture at demonstration sites.
When the VegNET RDOs spoke with the participants about their conventional irrigation practices, they learned that water was being applied once every day for 1-2 hours through a medium flow drip tap (one litre of water per drip per hour).
Fertiliser was applied through fertigation every 2-3 days when crops were watered.
From the data outputted by the soil moisture monitoring, they learned that, at the depth of 60cm, the soil is as wet as soil at 30cm – when water is applied.
Further findings
Explanation provided by the RDOs helped growers to realise that water was leaking down beyond the rootzone, which meant that water, along with fertiliser, was being wasted.
Furthermore, the fertiliser that was applied to the rootzone (at a 30cm depth) was being washed away by the water application on following days.
The grower has taken on board the RDOs’ suggestion that they try a new water and fertiliser application schedule and split the irrigation to water more than once a day, with shorter application times.
The trial aims to evaluate the benefits to the crop performance and to reduce water wastage by using soil moisture monitoring over the cropping season.
The RDOs will continue working with DPIRD collaborators to estimate the value of saved water and fertiliser throughout the duration of the trial.
* This article has been provided by vegetablesWA, and first appeared in the winter 2021 edition of WA Grower magazine.
Find out more
For more information, please contact Regional Development Officer Truyen Vo at truyen.vo@vegetableswa.com.au.
VegNET – Western Australia is a strategic levy investment under the Hort Innovation Vegetable Fund.
This project has been funded by Hort Innovation using the vegetable research and development levy and contributions from the Australian Government.
Project Number: VG19016
Cover image: Pictured left to right: VegNET – Western Australia Regional Development Officer Truyen Vo, Wildeye Technical Consultant Ben Taylor and Tan Pham, a Vietnamese Field Manager based in Wanneroo. Images courtesy of Truyen Vo.