Poster Presentation Australasian Plant Pathology Society Conference 2025

The effects of drought management practices on the soil food web in South Australian Broadacre cropping (#126)

Katherine Linsell 1 , Liz Farquharson 1 2 , Amanda Pearce 1 , Amanda Cook 1 2 , Nicole Baty 1 , Buddhi Chaudhary 1 , Sam Trengove 3 , Sean Mason 4 , Zoe Starkey 1 , Rhiannon K Schilling 1 2
  1. SARDI, Urrbrae, SA, Australia
  2. College of Science and Engineering, Flinders University, Adelaide , SA, Australia
  3. Trengove Consulting, Bute, SA, Australia
  4. Agronomy Solutions, Hindmarsh, SA, Australia

Drought is an ongoing constraint in Australian broadacre cropping reducing production and causing substantial economic loss. Drought stress negatively influences the abundance, diversity and functioning of microbial communities, which are crucial for many soil functions and ecosystem services including nutrient cycling, soil structure and control of soilborne diseases. The project aims to evaluate soil biological health indicators under different soil improvement practices applied to manage drought and climate change in broadacre cropping across South Australia (SA).

In 2024, the project utilised four replicated field trials evaluating different soil amendments on wheat production in SA across different soil types and rainfall zones. Treatments included amendments with different types of organic amendments (manure, biosolids), synthetic fertilisers, sugars, soil wetters, and antioxidants. Both pathogenic and beneficial soil organisms were measured using qPCR from DNA extracted from soil cores collected for each plot in Spring. Results from the first year of trials will be presented assessing;

  • The abundance of 9 free living nematode taxa. Nematode community analysis and derived indices are widely used to assess the structure, function, and resilience of soil food webs. We propose some of these amendments will promote more complex soil food webs with more mature and structured communities composed of higher trophic groups, and thus more resistant communities that and can buffer the effects drought.
  • The abundance of 14 cereal soilborne pathogens (fungi and nematodes). Organic soil amendments are known to reduce soil borne disease through different mechanisms including the establishing suppressive microbial communities or proliferation of specific antagonistic microorganisms. Reducing soilborne pathogens and subsequent soil borne diseases is critical in protecting root systems and their ability to access water and nutrients under drought conditions.
  • Arbuscular Mycorrhizal Fungi (AMF). AMF can help the plant overcome water and nutrient stress by enhancing nutrient and water transport and uptake, osmotic adjustments and improving antioxidant activity.

An improved understanding of the mechanisms underlying microbial responses to drought will be crucial for the development of strategies to improve crop production under drought conditions.

This project is supported by the SA Discovery Farms, through funding from the Australian Government’s Future Drought Fund and utilised trials co-supported by SAGIT.

  • I would like to participate in the poster speed presentation: Yes