By loading nutrients on graphene oxide sheets, scientists may be able to specifically target fertilizers for individual crops.

Researchers from the University of Adelaide have found that effective slow release fertilizers can be developed by loading essential trace elements onto graphene oxide sheets, lowering costs for farmers while also being environmentally friendly.

The researchers tested the graphene-based carriers with zinc and copper, both of which are micronutrients. The team will continue to test different macronutrients like nitrogen and phosphate.

“Fertilizers that show slower, more controlled release and greater efficiency will have reduced impact on the environment and lower costs for farmers over conventional fertilizers, bringing significant potential benefit for both agriculture and the environment,” Mike McLaughlin, Head of the University of Adelaide's Fertiliser Technology Research Centre, said in a statement. "Our research found that loading copper and zinc micronutrients onto graphene oxide sheets was an effective way to supply micronutrients to plants.

“It also increased the strength of the fertilizer granules for better transport and spreading ability,” he added.

According to the study, the chemical composition and successful loading of zinc and copper on the graphene oxide sheets was confirmed with X-ray photoelectron spectroscopy, thermogravimetric analysis and X-ray diffraction.

“The prepared Zn-graphene oxide and Cu-graphene oxide fertilizers showed a biphasic dissolution behavior compared to that of commercial zinc sulfate and copper sulfate fertilizer granules, displaying desirable fast and slow micronutrient release,” the study states. “A visualization method and chemical analysis were used to assess the release and diffusion of Cu and Zn in soil from GO-based fertilizers compared with commercial soluble fertilizers to demonstrate the advantages of GO carriers and show their capability to be used as a generic platform for macro- and micronutrients delivery.”

According to Dean Losic, the nanotechnology leader in the University’s School of Chemical Engineering and Director of the University’s Australian Research Council Research Hub for Graphene Enabled Industry Transformation, graphene has a high surface area and strength and is adaptable to bind to different nutrients.

McLaughlin explained that more work needs to be done before the graphene fertilizers can be used.

“It's still early days but there is no doubt that fertilizers with release rates more tailored to crop demand, and fertilizers with greater physical strength and robustness, will both improve grower efficiency of fertilizer application and efficiency of nutrient uptake,” he said. “Successful commercialization will depend on cost of graphene/graphene oxide and the ability to scale this process up, and integrate it into the commercial fertilizer production process.”

The Fertiliser Technology Research Centre was established in 2007 in partnership with The Mosaic Company, the world's largest combined producer of phosphate and potash, to develop and evaluate more efficient fertilizer products.

The study was published in ACS Applied Materials & Interfaces.