MU21004 - Marsh Lawson Mushroom Research Centre of Excellence
Key research provider: The University of Sydney and Applied Horticultural Research
What's it all about?
Following on from the previous levy investment Marsh Lawson Research Centre (MU16004), which began in 2017, this project supports the running and development of the Marsh Lawson Mushroom Research Centre (MLMRC) at the University of Sydney. The MLMRC is a world-class facility dedicated to mushrooms, and the research that takes place there will help the mushroom industry drive innovation, adopt best practices and tackle issues while encouraging new expertise in the industry.
There is a steering committee for the centre and its work, which has aligned the operation of the MLMRC to the Mushroom Fund’s Strategic Investment Plan and will help progress research needs and ideas that will be fulfilled through the centre.
The main objectives of the project remain strongly aligned with those of the previous project:
Maintenance and management of the current Marsh Lawson Mushroom Research Unit at the Darlington Campus, University of Sydney, to promote and carry out active research on all aspects of the growing and cropping of mushrooms.
Provision of research leadership to the mushroom industry, consulting with the industry to prioritise industry research needs through the MLMRC Steering Committee and providing targeted advice on mushroom-related research to the Mushroom Strategic Investment Advisory Panel (SIAP).
Supporting the transition to a new mushroom research facility at a site to be identified when this becomes available.
MU17007 - Feasibility of compost substrate alternatives for mushroom production
Key research provider: Murrang Earth Sciences
In 2019, this investment explored alternative sources of carbon for use in mushroom compost production by looking at the physical and chemical properties, compost quality, relative benefits and potential risks of a range of possible carbon sources. Wheaten straw is currently the most common carbon source used in mushroom compost production but is predicted to become more difficult to acquire and more expensive over time, so this investment was all about future-proofing the mushroom industry.
The research team investigated alternative carbon sources that could partially or completely substitute for wheaten straw in mushroom compost substrate, with the aim of improving business security for mushroom growers.
The research team conducted a literature review, industry consultation, and discussions with global researchers to develop a list of potential alternative carbon sources. Each was considered for its physical and chemical characteristics, plus its effects on composting and mushroom yields. Other assessment factors included consistency of supply volumes, purchase price, transportation, health and safety issues, and compliance to regulations and quality standards.
Four carbon sources were identified with the appropriate physiochemical properties plus viable cost and availability, which were wastepaper, forestry waste, corn stover, and sugar bagasse.
Both born stover and sugar appear to be ideal for use as a substitute for wheaten straw, however transport distances may pose a logistical hurdle. The use of wastepaper (either shredded or soft-mixed) in composting is limited by its physical properties, however it could replace around 20 per cent of wheaten straw in compost without negatively impacting mix porosity.
The researchers found that wheaten straw has unique properties that are difficult to replicate, and materials with good properties for composting that were also abundantly available were difficult to identify. The alternative carbon sources are also subject to similar price-competition due to their use in other industries, especially the feedstock industry.
The research team shared its results with the mushroom industry, as fully investigating the potential use of other carbon sources for complete or partial substitution needs to consider what changes to the conventional production system are required, including composting systems and culture practices for growing A. bisporus.
Project outputs
Compost substrate alternatives being considered, published on page 22 of the Australian Mushrooms Journal, Edition 3 2019
Feasibility of compost substrate alternatives: a project update, published on page 30 of the Australian Mushrooms Journal, Edition 2 2020.
MU17008 - Understanding and managing the impacts of climate change on Australian mushroom production
Key research provider: Applied Horticultural Research
Climate variability and change present a range of potential risks to the technical and economic viability of Australian mushroom growers, compost producers and support industries. This short project, which ran from 2019 to 2020, identified climate-related risks across production regions, now and into the future. It also worked with industry on a regional basis to look at how to manage these risks and how to reduce greenhouse gas emissions to help mitigate them, while providing education on how improving environmental performance can be used to a marketing advantage.
The research team began by performing a desktop review to summarise the latest science of climate change and the expected impacts that may affect the mushroom industry. It reviews how mushroom and compost producers in Australia and globally are adapting to the expected impacts of climate change, as well as reducing their environmental impact. The review is available here.
Identifying potential risks
The project team consulted 20 mushroom growers, representing 73 per cent of Australian production and seven composters. Each participant was asked about their climate risk preparations, as well as new strategies to manage climate-related impacts on their businesses. From these discussions, several key risks were identified (as below) and a summary document can be viewed here.
Availability of peat for casing
Availability, cost and quality of wheat straw for compost
Availability and quality of manure for compost
Impacts of temperature extremes on compost production, growing and transport
Energy – reliability of the power grid and costs of electricity and gas
Government emissions control policies
Water availability, cost and quality for compost production and mushroom growing
Pests and diseases, increased fly activity and the spread of disease, weed moulds and Trichoderma.
Case studies for adaptation and mitigation
The project team reviewed adaptation and mitigation options that are currently in use worldwide and developed six case studies outlining opportunities for the mushroom industry to consider, available to download here.
Recommendations for industry
The following recommendations are made to address gaps in knowledge and future R&D requirements. Together with the adaptation and mitigation options provided, the mushroom industry can reduce future climate change risks.
Identify and test alternative casing materials
Optimise compost made from lower quality, shorter straw and different manure sources
Evaluate the use of soil moisture sensors for managing irrigation in mushroom growing
Develop a smart cookout approach using qPCR disease identification to determine pathogens present and determine when cookout is needed.
Understand cookout timing and temperatures required to control specific diseases in growing rooms.
Investigate likely changes in mushroom disease, including smoky mould
Investigate the technical feasibility and marketing opportunities of carbon neutral mushrooms
Establish a solar buying group for mushroom producers
Pilot biogas energy generation on-farm.
MU16004 - Marsh Lawson Mushroom Research Centre (MLMRC)
AHR Employees Sandra Evangelista and Tyler Kristensen working in the Marsh Lawson Mushroom Research Unit
Key research provider: The University of Sydney and Applied Horticultural Research (AHR)
This project supports the running and development of the Marsh Lawson Mushroom Research Centre (MLMRC) at the University of Sydney. The MLMRC is a world-class facility dedicated to mushrooms, and the research that takes place there will help the mushroom industry drive innovation, adopt best practice and tackle issues, while encouraging new expertise in the industry.
During the project, the facility will grow in size and capability, with the addition of new growing rooms and a purpose-built compost research facility.
What was it all about?
From 2017 to 2022, this investment supported the running and development of the Marsh Lawson Mushroom Research Centre (MLMRC) at the University of Sydney. The MLMRC is a world-class facility dedicated to mushrooms and the research that takes place there will help the mushroom industry drive innovation, adopt best practice and tackle issues, while encouraging new expertise in the industry.
This project was delivered jointly by The University of Sydney, who provided and maintained the research facilities and took charge of employing growers, and Applied Horticultural Research (AHR), who provided the management services outlined in the proposal.
The Marsh Lawson Mushroom Research Centre was directed by an industry-focused independent Steering Committee that prioritised research directions and led planning discussions towards transitioning to a new research facility. This Steering Committee has now developed into an important source of technical expertise that provides an industry overview into mushroom research funded by Hort Innovation and the industry levy.
Key impacts for the project include input into shaping the research direction for the mushroom industry, maintenance and improvement of the purpose build mushroom research facility at the University of Sydney, and progress on transition to new growing and composting research facilities.
The project, either directly or through the research facility has contributed the following outcomes for the Australian mushroom industry:
Commercially available PCR-based disease testing of compost and growing facilities
Assessments of recycled organics as a substitute up to 25 per cent of the peat used casing soil
Data to support a label extension of the fungicide metrafenone to control mushroom disease
Improved understanding of the microbial processes in mushroom compost production which may lead to more productive or functionally improved compost
Evaluation of products that can improve the whiteness and freshness of mushrooms.
ACT NOW
The MLMRC project delivered a total of 11 webinars aimed at producers, communicating research outcomes involving Australian and international researchers.
Watch the webinars below:
MU17004 - Optimising nitrogen transformations in mushroom production
Key Delivery partner: The university of sydney
This project will ultimately help mushroom growers to optimise the rate and timing of nitrogen additions, to achieve maximum yield and nutritional value.
The project team are currently exploring the fate of nitrogen used in mushroom production and composting, including developing a better understanding the microorganisms that are involved in transforming the nitrogen that is added throughout the mushroom production process into other forms. They are also looking at ways and timings to maximise nitrogen use efficiency and promote nitrogen retention for composting, and more. A best practice guide for growers will be produced out of the project findings.
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This project explores the fate of nitrogen in mushroom compost and mushroom production, allowing growers to optimize the rate and timing of nitrogen additions to achieve maximum yield and crop nutritional value. Work in the current project period has focused on the timing of supplements added to compost during cropping, and on the efficacy of microbial inocula added during spawn run in promoting mycelial growth.
Supplementing crops with nitrogen immediately before each flush provided an increased yield of about 7 per cent, with much of this increase occurring in second flush. The nitrogen content of mushroom caps and stipes was found to be significantly enhanced in mushrooms from second and third flush, which contained 7-8 per cent N (dry wt) compared with 4-5 per cent N (dry wt) in first flush mushrooms. Similar results were found on a commercial farm, suggesting that late-flush mushrooms may be described as “high nitrogen” versions of the crop.
Test of mycelial growth promotion with combinations of abundant compost bacteria including Pseudoxanthomonas, Bacillus and Chelatococcus revealed that stimulation of mushroom growth was dependent on co-inoculation with the dominant fungus Mycothermus (formerly Scytalidium). Work is continuing to establish the effect of these treatments on crop yield.
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Since the last project update, work has focused on completing an overall nitrogen balance for mushroom composting and cropping, reviewing alternative nitrogen sources for Australian composters, and designing and testing microbial consortia for compost inoculation.
Detailed measurements taken during Phase 2 of composting showed nitrous oxide production much lower than expected, and ammonia released by the compost largely reabsorbed. Major loss of nitrogen during composting therefore occurs primarily during Phase 1, partly as leachate and partly as ammonia release.
Calculating an industry average for these losses is difficult because of variation in the proportion of recycled leachate used by different composters for straw wetting. Further limitations to nitrogen balance calculations were identified in the overall mass losses experienced by all composters.
Possible alternative nitrogen sources for the Australian mushroom industry were reviewed, focused on agricultural by-products already tested overseas. The need for an up-to-date inventory of the types, quantities, and localities of agricultural and food production by-products was highlighted. Local availability is particularly important in establishing test experiments for these feedstocks.
Ten bacterial taxa were identified as potential consortium for compost inoculation. The dominant genera are Pseudoxanthomonas, Chelatococcus, Chelatovorans, Thermus and Thermobacillus. These will be combined with Mycothermus, the dominant fungus in Phase 2 compost, for stability and functionality testing.
While some impact due to COVID-19 restrictions disrupted research progress, the team continues to work to mitigate any delays.
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Since the last project update, a survey of 10 Australian mushroom composting facilities across four States has been completed. It included a comparison of composting management processes and compost bacterial activity. The results delivered initial insights to inform the selection of compost yards for further nitrogen management analysis.
The survey revealed that an average of 10 per cent of input nitrogen is incorporated into the mushroom crop, and about 20 per cent of the total is lost as leachate or nitrogen-containing gases. Nitrogen losses also occur from the compost and casing during cropping. To better understand this process, two cropping trials have been established in the Marsh-Lawson Mushroom Unit. Analysis has unfortunately been delayed due to Covid-19 impacts.
The team have isolated specific microorganisms from high temperature composts, with the dominant strains identified by DNA sequencing and characterised. Interactions between the two main compost fungi (Mycothermus thermophilus and Agaricus bisporus) and the dominant Phase 2 bacterial taxa (Pseudoxanthomonas spp) have been examined in more detail. Due to the high relevance of these bacterial taxa, their entire genetic sequence has been determined, with analysis of their functional capabilities ongoing.
The compost isolate collection contains 175 isolates of 58 different species. This is now sufficient for the design of potential compost inoculation treatments aimed at optimising the composting process.
The reporting period coincided with Covid-19 related work and travel restrictions, resulting in considerable disruption to research progress. The team will continue to share results with industry as opportunities become available.
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The project team commenced work in January 2019 and have already isolated and characterised a substantial collection of bacterial strains taken from a range of Australian compost yards in New South Wales, Victoria, South Australia and Tasmania. These samples represent the dominant cultivable bacteria in composts and will underpin the rest of the project.
Many of the most prevalent strains identified were very similar, despite coming from different geographical areas, confirming the conserved biological nature of mushroom composting across Australia.
Analysis of the composts revealed that many of the dominant species have not yet been captured in the strain collection. These are now being targeted using specifically designed growth media and selective conditions.
A detailed survey regarding current nitrogen management by Australian composters was started, with field trips to facilities in Victoria, New South Wales and South Australia, and visits planned to Queensland. The results of this confidential survey will be used to identify composting yards that represent the diversity of processes in the Australian industry, informing the project’s detailed nitrogen balance studies.
ACT NOW
Read an overview of the project in this article, Optimisation of nitrogen use in mushroom production, published on pages 34-35 in the spring 2019 edition of the Australian Mushrooms Journal.
Project outputs:
Australian Mushrooms Journal, Spring 2019 edition page 30
MU17006 - Developing a database of bio-markers for compost quality control to maximise mushroom production yield
Key delivery partner: The University of Sydney
The quality and yield of button mushroom crops are critically dependent on the quality of compost used. Beginning in June 2019, this investment is exploring how microbial populations within compost can be used to understand, measure and manipulate compost quality.
The project team’s work involves investigating microbial populations across a range of mushroom composting facilities. This includes looking at the microbial population dynamics at different points along the composting timeline, how they align with other compost quality indicators and correlating everything back to mushroom crop yield and quality.
The research will culminate in a database of compost ‘bio-markers’ (microbe indicators) for the industry, which will be able to be used to assist in maximising productivity and crop outcomes.
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Progress in this project was severely impacted by the COVID-19 lockdown in the second half of 2021, and work in this period was therefore limited to software development and training.
Sample collection at participating compost yards for the feasibility study recommenced in December 2021, and was completed by April 2022.
These samples represent a time-course from three successive crops at four independent mushroom composting facilities across New South Wales, Victoria and South Australia. Analysis of chemical compost quality markers in these samples (pH, moisture, total C and N, soluble C and N, microbial biomass, humification index, nitrification index) is nearly complete, and the microbial community analysis of these samples has been completed.
The results indicate good reproducibility between compost crops at Phase II but considerable variability between individual crops at earlier stages of the composting process, and this will be used to inform the design of the full scale compost biomarkers study.
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Since project commencement, progress has been severely impacted by COVID-19 travel restrictions, leading to a temporary pause in research activites.
Restarting in January 2021, the team focused on developing effective and reproducible compost sampling strategies.
The initial phase worked to assess changes in microbial diversity and other compost quality parameters in three successive compost crops from yards in three different States. With sampling almost complete, the analytical methods required for analysis have been optimised.
The results from this study are now being used to prepare methods for a much larger one-year study.
Project outputs
Australian Mushrooms Journal, spring 2019 edition page 32