The deep, sandy soils of Western Australia’s Swan Coastal Plain are among the most infertile in the world.

They’re also where many of the state’s vegetables are produced, however, and growers have long struggled with the low ability of these soils to retain nutrients or moisture.

More than 60 percent of irrigation water and nitrogen fertiliser applied to vegetables on the sandy soils of the Swan Coastal Plain leach past the rootzone. The story’s not much better for phosphorus or potassium.

Against that backdrop, input costs continue to grow, water allocations tighten, and concerns about fertiliser runoff into waterways and wetlands increase.

In an effort to address this problem, WA’s Department of Primary Industries and Regional Development has launched a new levy-funded project to develop a system for capturing leached nutrients and irrigation water from below the crop’s root zone, and recycling this water back onto crops as irrigation.

The project, which runs until February 2030, will investigate the use of geomembranes installed below the root zone of crops to collect leachate and divert it into dams for reuse.

We had a chat with DPIRD research scientist Dr Valeria Almeida Lima about the project, and how this new system might work.