South Australian researchers look to turn almond waste into compost

Only about 30 per cent of the almond fruit is edible, with the remainder inedible hull and shell regarded as a waste product.

But a South Australian Research and Development Institute (SARDI) team is working with almond grower, Select Harvests, to create a high-nutrient compost made of about 50pc almond waste.

The product is naturally high in potassium and will be combined with other natural ingredients such as lime, gypsum and rock phosphate.

A trial involved substituting 30pc of chemical fertiliser with the almond compost blend and resulted in a significant increase in soil carbon and fertility, with no adverse impacts on tree health, orchard manageability or the quantity or quality of the crop.

SARDI research scientist, Nigel Fleming, said ongoing research in the area was critical for Australian agriculture.

"While we're yet to see significant yield responses to organic amendment we've found improvements in soil parameters," he said.

"We're seeing increased soil fertility, carbon levels, the ability to hold nutrients, and biological activity as well. So these systemic improvements in the soils have the potential to increase production efficiency and perhaps minimise the requirement for external fertiliser sources."

Select Harvests senior technical officer, Upul Gunawardena, said the company was looking at various cost-effective ways of using almond waste.

"Select Harvests in the largest integrated almond company in the world and has a goal of becoming carbon neutral by 2050," he said.

"This compost has a number of carbon benefits. It also enhanced subsoil root development so all these things are increasing and enhancing carbon sequestration in the soil."

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