Waste canola oil becomes a key to improved fertiliser
A new type of slow-release fertiliser that results in better plant health and less wasted nutrients has been invented at Flinders University by Dr Justin Chalker and his team in the Institute for NanoScale Science and Technology. The fertiliser is released slowly into soils because it is encapsulated in a renewable polymer made from canola oil, which is an abundant food waste product. “We are taking recycled cooking oil, converting it into a fertiliser component, and using it to grow more food,” explains Dr Chalker. “It’s is an important way to contribute to a circular economy.” Dr Chalker and his team have created a polymer from waste canola oil and elemental sulphur (a by-product from the creation of petroleum products) as an organic coating for the fertiliser components ammonium sulphate, calcium hydrogen phosphate and potassium chloride. Nutrients from this slow-release fertiliser are released to the soil after water slowly dissolves and leaches the inorganic components from the polymer-nutrient block. In tests conducted on tomato plants, researchers found the nutrients were released in a controlled fashion, resulting in less wasted fertiliser and better health for the plants growing in this soil. Results from this study (Sulfur Polymer Composites as Controlled-Release Fertiliser, DOI: 10.1039/C8OB02130A) are featured in a special New Talent issue of the journal Organic and Biomolecular Chemistry — which features Dr Chalker among selected leading young researchers from around the world. The polymer, being formed from waste products that are abundant, is cheap to produce, making it an ideal solution for producing superior fertilisers that are a necessary part of meeting global food production demands, especially in areas with poor soil quality. A significant additional benefit of the polymer’s slow release qualities is that it prevents fertiliser runoff, which protects the environment, and greatly improves the efficiency of the fertiliser […]