Dishing the dirt on subsoil manuring

Subsoil manuring can completely transform even the most hostile ground – but how can we make it affordable for farmers?

La Trobe University PhD candidate Corinne Celestina believes soil microbiomes hold the answer.

“Subsoil manuring has the potential to revolutionise cropping in high rainfall areas of southern Australia, and is an incredibly profitable practice,” said Ms Celestina.

“Unfortunately it’s also expensive – the process can be well over $1200 a hectare, a cost which is out of reach for many farmers.”

Subsoil manuring works by incorporating organic matter, such as poultry litter, into dense clay subsoils. The process results in significantly better soil quality, which allows the movement of air and water, as well as root growth. It also provides nutrients to feed the plant and the soil microorganisms.

While much is known about the changes to physical and chemical properties during subsoil manuring, little is known about the processes’ impact on the soil microbial community.

“Just like the human gut, soil has microbiomes which are crucial for healthy plants,” Ms Celestina said.

“During my project, I hope to uncover the key biological processes involved in subsoil manuring and how the process affects soil properties, leading to higher crop yields.”

She hopes a more complete understanding of soil microbiology will lead to more cost-effective solutions.

“My research involves field sampling and a range of controlled environment studies, where I’ll trial different types of organic matter, soil types and crops,” Ms Celestina said.

“If we can better understand the factors behind the yield response, we may be able to shortcut the process and find more affordable options.”

Ms Celestina has been digging deep since her research began in July 2015.

“Initial results show that subsoil manuring is altering the communities of bacteria and fungi in the subsoil, and that the soil microbiome shifts to more closely resemble that of the fertile, well-structured topsoil”

Ms Celestina was recently awarded two prestigious scholarships, the Tim Healey Memorial Scholarship and the Grains Research and Development Corporation’s Grain Industry Research Scholarship, to further her research.

Photo: PhD candidate Corinne Celestina

Media contact Briena Barrett: 0432 566 014

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