Investment in science and industry development key to profitable agrifood sector 2

HIGHLIGHTS

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  The use of agricultural lime has remained high and, while not yet at the desired level to address existing and ongoing acidity statewide, there are good signs that specific regions are making progress.
  
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  A new Royalties for Region-funded ‘Watering Western Australia’ project through the Department of Water will provide valuable information to further support growers and measure changes in soil condition.
  
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  We will conduct a ‘third time of sampling’ following the gains made in previous projects (2006–2013), which developed soil pH risk maps.
  
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  Over the past 12 months, we have assisted three significant external studies:
  

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  ‘Lime transport routes’, with the Grainbelt Development Commission
  
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  ‘Lime Situation Report 2015’, prepared for South Coast Natural Resource Management by Julia Fry
  
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  ‘Evidence for the economic impacts of investment in National Landcare Programme activities’, Department of Environment, Canberra.
  

Funding and collaborators

GRDC, Lime WA Inc., Rural Solutions SA, Central West Farming Systems (NSW), Southern Farming Systems (Vic), Desiree Futures

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DAFWA Research Officer Chris Gazey sprays universal pH indicator on soil

Getting lime in deeper and quicker to recover acidic soils

Science team: Chris Gazey (project Leader), Dr Gausul Azam, Daron Malinowski, Dr Craig Scanlan

Liming is an effective ameliorant for soil acidity (low pH) which occurs in much of southern WA.

Our soil acidity group is developing ways to maximise the benefits of applying lime to help growers (particularly in the eastern WA grainbelt) to manage subsurface acidity more cost effectively.

DAFWA and UWA researchers are looking at three key areas to increase the returns to growers from managing soil acidity:

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  boosting the benefits from conventional liming using limesand, limestone or dolomite. In particular, we aim to develop and assess incorporation techniques for old (applied in the past few years) and newly applied lime
  
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  assessing the potential for common alternative lime sources, such as liquid limes or other granulated or prilled products
  

We have identified field trial sites for 2017 and also paddocks where growers have carried out some level of soil disturbance. We will use these sites to assess the effectiveness of incorporation using varied techniques.

With Rural Solutions South Australia, we will establish a site on the Eyre Peninsula in recognition that susceptible soil types in SA are also at risk of increased acidity. The aim will be to help growers avoid the development of the situation that much of WA now faces.

As the project progresses, we will work closely with the other soils projects, particularly those in the Soils Constraints – West group, to develop an economic framework that will allow growers to make informed decisions about integrated management of multiple soil constraints.

In addition, we will continue to assess a range of liming products in laboratory and glasshouse experiments for their capacity to neutralise soil acidity, using the results to guide experimental treatments in the field in the future.

HIGHLIGHTS

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  We have established a long-term field experiment at Merredin to examine the capacity for N fertiliser strategies to decrease acidification rates.
  
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  Soils Constraints – West projects and growers have recently shown that significant incorporation of limed topsoil is possible behind deep ripping points with plates designed to hold the soil open for longer. Understanding the soil and lime behaviour will be a focus of further work.
  
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  An economic framework to assess management strategies for multiple soil constraints is being developed under the Soil Constraints – West project 'Sub-soil constraints – understanding and management’. Our research will contribute to this framework.
  

Funding and collaborators

GRDC, UWA, Rural Solutions South Australia.

DAFWA Research Officer Gaus Azim

Know your enemy: subsoil constraints

Science team: David Hall (project leader), Dr Shahab Pathan, Caroline Peek, Grey Poulish, Dr Geoff Anderson, Jeremy Lemon, Chris Gazey, David Dodge, Glen Riethmuller, Dr Stephen Davies, Grant Stainer, Glenn McDonald, Wayne Parker, Dr Ed Barrett-Lennard, Dr Karen Holmes, Dennis van Gool, Ted Griffin, Dr Liz Petersen

Subsoil constraints cost WA grain growers more than $1 billion per annum in lost production (Petersen 2016).

The constraints that limit plant growth include nutrient disorders (toxicity, deficiency), compaction, acidity, sodicity and transient salinity. These constraints restrict root depth and function to the extent that water and nutrients can’t sustain production at or near the rainfall limited yield potential.

Efficient use of rainfall is important to make the most of reduced rainfall and associated climatic effects in the grainbelt. Often growers lack sufficient diagnostics to confidently identify and manage these subsoil constraints.

This project is designed to increase profitability through improved diagnostics and management options.

A combination of glasshouse and field experiments has been established to characterise crop yield responses to subsoil constraints. Experiments are being conducted on acidic sandy soils through to alkaline clay soils from Dalwallinu to Esperance.

Our research is focusing on deeper tillage and amendments (fertiliser, organic materials, gypsum, lime) to improve root growth, soil water storage and crop yields.

A key outcome of this project is to refine tools to identify subsoil constraints and their impacts on crop production. These tools range from assessment of the relationship between plants and soil through to economic models that can help growers set priorities for management options to reduce subsoil constraints.