Soil Constraints – West: a GRDC initiative to develop soil management systems for the future

Key Messages

  • A $33M investment over five years into major soil constraints that limit crop production – soil acidity, compaction, non-wetting soils and subsoil constraints – to develop sustainable soil management systems for the future.
  • Input from GRDC and research agencies in WA (DAFWA, Murdoch Uni, CSIRO), grower and industry groups, linked to other soil investments in WA, under the guidance of a Steering Committee.
  • A component of a new National Soil Constraints Initiative run by GRDC to start in 2015, to maximise returns to industry from research $$ invested.


Soil Constraints – West is a major collaborative initiative to develop and deliver solutions for a range of soil constraints which limit productive grain cropping in Western Australia; these are non-wetting soils, subsoil constraints, soil compaction and soil acidity. The GRDC, Department of Agriculture and Food (DAFWA), CSIRO and Murdoch University are providing more than $33 million of new research investment to address these significant issues over the next five years.

The Soil Constraints - West Initiative was developed by the GRDC Western Regional Panel after consultation with WA grain growers, and the GRDC Regional Cropping Solutions Networks (RCSNs). It adds to the GRDC’s already substantial western region investment in soil research including soil nutrition, soil carbon and soil ‘health’. The research takes place largely in WA, but the findings are relevant to other southern Australian cropping areas. As well as conducting new research and extending results to farmers, there is a strong focus on training the next generation of researchers.

A Steering Committee coordinates the Soil Constraints – West projects and meets a minimum of twice per year. This committee has an independent chair, and includes members from each of WA’s five RCSNs, the four soil constraints projects, and GRDC panel and programs. This committee ensures that the research is regionally relevant and that there is flow of information between researchers, industry and growers.


GRDC is a major investor in grains industry R and D, in partnership with many agencies in WA and nationally; GRDC also has substantial direct involvement with industry via the grower groups and the RCSN networks.

GRDC has often invested in single projects – typically 3 to 5 years, often with a single agency as the research provider, and limited guarantee of further research funding (irrespective of the quality of the project). More recently, however, GRDC have explored the interactions between different components of farming systems and invested in ‘initiatives’, whereby several projects collaborate on an investment ‘theme’, with opportunities to continue investment in the future as either clear research interactions and leads develop, or there is a need for greater development, communication or extension with industry to encourage growers to consider different farming strategies.

Examples of Initiatives include:

  • Water Use Efficiency, managed by CSIRO
  • MPCN (More Profit from Crop Nutrition)
  • Soil Biology Initiatives
  • Grain and Graze
  • Precision Agriculture (SIP09)
  • National Frost Initiative

For soils, a sub-soil constraints Initiative (SIP08) ran from 2007 – 2010, and a new National Soil Constraints Initiative starts in July 2015.

GRDC’s Western Panel established the Soil Constraints – West Initiative in 2014, and it is this program that will be discussed here.


Why have a Soil Constraints - West Initiative?

There is a common perception that WA soils are ‘different’ and need dedicated local research focus to deliver returns to WA. WA research partners have a history of working together over many years and can share expertise, equipment and sites. It can also be argued, however, that the similarities between soils are greater than the differences, and WA soils exist on one end of a soils ‘continuum’ across Australia; a link to the new National Soils Initiative will provide additional value and return on research investment in the West.

There is a well-established Grower Group Alliance, and now the RCSN network which facilitates validation and extension of research outputs to growers and industry. Growers recognise many opportunities to improve the physical, chemical and biological stability of soils to build a sustainable soil management system for future crop and pasture production, but need guidance to work out the technical feasibility and cost effectiveness of different management options for all constraints.

The research included in the Initiative aligns with the GRDC and RCSN research priorities, and many of the problems identified in the DAFWA ‘Report card on sustainable natural resource use in agriculture’. For GRDC, the research is consistent with the stated aims of Themes 4 and 5:

  • Theme 4, Advancing profitable farming systems……
    - “growers adopt integrated management of opportunities and constraints to increase profit and minimise risk across seasons…” and
  • Theme 5, Improving your farm resource base…
    - “growers adopt agronomic practises that improve the chemical, physical and biological health of the soil for sustained productivity”.

For the RCSN network, the RCSN Western Region Annual Report confirms that ‘Soil constraints’ were highly ranked across RCSN regions:

Table 1: Soil constraints which were highly ranked by RCSN groups 2012-13

Albany Esperance Geraldton Kwinana west Kwinana east
Non-wetting Yes Yes Yes - Yes
pH and acid soils Yes (Yes) Yes Yes -
Compaction Yes Yes Yes - Yes
Sub-soil constraints* (Yes) (Yes) - Yes Yes

* Identified as limitations to water supply

2015 is also the ‘International Year of Soils (IYS)’, and it is appropriate that WA has a ‘flagship’ Initiative that recognises the importance of soils in food production and the management of rural landscapes, and emphasises the complexity of managing soil constraints in a changing climate and with pressure on terms of trade.

Key objectives of the IYS, endorsed by the Food and Agriculture Organisation of the United Nations:

  • to create full awareness of all stakeholders about the fundamental roles of soils for human life
  • to achieve full recognition of the prominent contributions of soils to food security and nutrition, climate change adaptation and mitigation, essential ecosystem services, poverty alleviation and sustainable development
  • to promote effective policies and actions for the sustainable management and protection of soil resources
  • to sensitize decision-makers about the need for robust investment in sustainable soil management activities, to ensure healthy soils for different land users and population groups
  • to advocate rapid enhancement of capacities and systems for soil information collection and monitoring at all levels (global, regional and national).

Which projects are included in this phase of Soil Constraints – West?

1. Delivering enhanced agronomic strategies for improved crop performance on water repellent soils. DAW00244 – Steve Davies (DAFWA), with Phil Ward and Margaret Roper (CSIRO), and Richard Bell and Richard Harper (Murdoch University).

Nearly 3.3M hectares of Western Australia's agricultural soils are at high risk of soil water repellence with a further 6.9M hectares at moderate risk. Soil water repellence is widespread and often severe on sandy soils, and results in poor, patchy and delayed crop and pasture emergence. The estimated annual cost of lost production from water repellence is $250M (Herbert 2009). The project will:

  • Undertake fundamental and applied research to increase knowledge of soil water repellence in WA cropping systems and further develop and enhance existing strategies to manage soil water repellence.
  • Deliver an extension strategy to growers, consultants and agronomists giving them improved capacity to confidently select the best management options for the range of water repellent soils that occur on WA farms.
  • Build and retain agricultural soils research capacity in the Western region through the appointment and training of PhD students, a post-doctoral fellow and regionally based graduates. Industry capacity will be further improved through the targeted delivery of findings and training to grower groups, consultants and agribusiness.

The research undertaken by the project will strengthen the findings of previous R&D and will address critical grower and industry research needs. Research will ascertain differences in the nature of soil water repellence across WA soil types and environments. This knowledge will be utilised to develop and target water repellence management options for affected soils.

2. Soil Acidity is limiting grain yield - Coordinating the improved management of soil acidity in Western Australia and the GRDC Southern Region. DAW00236 – Chris Gazey and Liam Ryan (DAFWA).

This project coordinates a national effort to effect a step change in the management of soil acidity in the Western and Southern GRDC regions. Soil acidity is widely recognised as a land degradation issue and a constraint to sustainable and profitable agriculture by growers, state and federal governments and R D & E funders. Acidity is severe and widespread, and a major risk to production; it is estimated that soil acidity costs WA agricultural producers $498 million per year in lost productivity.

The contributing factors to soil acidification under the current farming systems are well understood, as are the best practice management systems. The disconnect has been that adoption of soil testing to depth to determine pH and develop appropriate management plans, which must include the appropriate application of lime where soil pH is less than the recommended targets, has been less than optimal.

It is expected that this project will double agricultural lime use in Western Australia from the 2010 base. To achieve this, a whole of industry approach is required and this project will drive that change through the coordination of an industry wide working group, on-going education, extension and training of key private and government advisors/consultants that will then support growers into the future.

The industry working groups includes representatives from government departments and private enterprise who have experience from the lime pit to the farm and of the administrative aspects including mining (of agricultural lime) and transport. The group will be asked to revisit the major barriers to adoption of liming by growers and propose solutions to overcome them while considering additional challenges posed by the desired doubling of lime use. It is envisaged that the group will propose 'mini-projects’ or ‘investigations’ to address the issues raised and these will form part of the activities of the project.

The project aims to work closely with three grower groups, the Liebe group, West Midlands group and the Moora Miling Pasture Improvement group, to test and improve a range of tools. Existing and new information including data from lime trials, publications and recommendations will be used to develop or improve a collection of simple calculators which will enable growers to make informed decisions to ensure that they are confident about management decisions including an understanding of the likely outcomes if the level of soil acidity on their farms is not managed appropriately.

3. Subsoil constraints - understanding and management. DAW00242 – David Hall (DAFWA), with Yvette Oliver (CSIRO).

Subsoil constraints (SSC) cost WA growers more than $600 million pa in lost production (Herbert 2009). The constraints include subsoil: acidity, nutrient disorders (deficiencies, toxicities), compaction, sodicity/waterlogging/permeability contrast and alkalinity/boron/transient salinity. These constraints reduce root depth and function to the extent that water and nutrient levels are insufficient to sustain production at or near the rainfall limited yield potential.

Often the diagnostics are insufficient to enable growers to confidently identify and manage constraints. Confidence to predict the severity and extent of these constraints is important given that many farmers are experiencing reduced margins due to drying climates and increasing costs relative to returns.

This project will increase profitability through efficiency and production gains associated with improved subsoil management. The gains may be in the form of amelioration but may also be in the form of mitigation where the constraints cannot be profitably rectified. Outputs will result in improved yields, reduced costs and enhanced confidence by growers and their advisors in managing SSC to soil type. This work builds on outputs from other GRDC funded projects including the Subsoil Constraints Initiative (SIP08), focus paddocks (DAW00213), precision agriculture initiative (SIP09), soil acidity, water-use efficiency initiative (DAW00193), as well as the more recently GRDC funded project on measuring and managing soil water (CSP00170).

4. Minimising the impact of soil compaction on crop yield. DAW00243 – Paul Blackwell and Doug Abrecht (DAFWA).

By July 2019, the project will significantly improve grower and consultant knowledge of profitable options to better manage subsoil compaction in WA cropping soils. Soil compaction is widespread, but the exact severity and trend is unknown. Annual cost of compaction as lost production is estimated as $333M with additional losses associated with soil structure decline. Subsoil compaction holds back crop growth on WA soils by restricting root growth and increasing the risk of waterlogging in the soil profile. Compact soils can also restrict healthy activity of soil biology. These effects can reduce grain yield and increase costs.

Previous R&D through DAFWA, GRDC and NACC has identified and provided management options for better control of soil compaction. These include deep cultivation (potentially 20 – 30% grain yield increase), controlled traffic systems (10% more grain yield), repeated deep cultivation and minimising inputs to protect profitability. However, declining terms of trade and poor seasons have obliged grain growing farms to increase in size and improve machinery efficiency. Increased machinery efficiency comes from greater capacity, size and loaded weight. Higher axle and track loads increase the depth and severity of subsoil compaction, commonly to 500mm rather than 300mm depth. Optimum management strategies now involve both traffic control and removal of deep subsoil compaction. Profitable employment of such methods requires revisiting deep ripping and employing more efficient methods; shallow leading tines can be part of this strategy; this is a proven method to alleviate deep compaction and save fuel.

Controlled traffic farming (CTF) systems were introduced to WA 10-15 years ago and have been well adopted. CTF is estimated to approximately double farm profit, however many growers have found difficulty matching the more recent sizes of machinery and are reluctant to compromise efficiencies to enable a good CTF fit. This project will therefore provide the WA grains industry with continued support to evaluate the financial and environmental benefits of CTF and especially the planned transitions growers can adopt to capture the benefits.

Motivation for the project and identification of suitable priorities will come through the regional groups supporting sites hosted by champion growers. Sites to demonstrate better subsoil compaction management are planned at Chapman Valley, West Moora, Merredin, Gnowangerup and Esperance. Principal trials at the sites will investigate very deep ripping and the nutrient use efficiency of soil in CTF systems, especially for nitrogen. Information on each site will be available in digital form from dedicated web pages and accessible through QR codes on sites at each site. The South East Premium Wheat-growers Association (SEPWA) will help develop this digital platform. A support network for CTF growers will be established in collaboration with the West Australian No-Till Farmers Association (WANTFA). The Grower Group Alliance (GGA) and Northern Agricultural Catchment Council (NACC) will assist the collaboration with grower and NRM groups.

Communication of technical information to the WA agricultural industry and the banking sector will be through newsletters, technical articles in the agricultural press and media outlets, as well as through DAFWA, NACC and GRDC websites and those of collaborating organisations, such as grower groups, NRM groups, WANTFA and the Australian Controlled Traffic Farming Association (ACTFA) and SPAA. Assistance for decision making will come from COMPMAN (COMPaction MANager). This general decision support system will be available in an APP for smartphones and tablets and as a web based form. COMPMAN will also provide links to suitable technical material in document and video form to help strengthen evidence for practice change.

How is the Initiative managed?

A Steering Committee has been established to oversee the work in the projects, and encourage interaction between research agencies and growers. The Committee is also responsible for reviewing progress, and providing advice to GRDC on future research directions and investment strategies to deliver sustainable soil management to the agricultural industries. The Steering Committee has a representative from each agency involved in the research, and from each of the RCSN networks; GRDC is represented by Western Panel member John Even, and Canberra Manager Tanya Robinson; there is an independent chair (Bob Belford); The Committee meets at least twice a year, with separate forums for planning trials and other activities, and disseminating information. RCSN members on the Steering Committee are Mark Pearce (Albany), Craig Topham (Geraldton), Quenten Knight (Esperance), Scott Dixon and Bob Nixon (Kwinana East), and Tony White (Kwinana East).


The research topics in this Initiative are all familiar, and have research histories that go back many years. It is now recognised that these constraints rarely exist in isolation but interact so that the overall impact is greater than that attributable to any single constraint: for example, improving root growth by ameliorating subsoil acidity with lime will be of little value if that subsoil is highly compacted or sodic. Technology and farming systems also advance, and solutions that were acceptable in previous years (with different yield levels, input costs and product prices) may no longer be appropriate. Importantly, soil constraints limit the effective use of rainfall and stored soil water – if root growth and nutrient transformation are restricted, crops and pastures will be unable to access water irrespective of seasonal rainfall.

Research on many other soil factors is not included in this Soil Constraints West initiative – e.g. soil nutrition, the importance of organic matter and soil biology, interaction with tillage, stubble retention and other agronomic practices. The challenge for the Initiative is to provide information of value to other soils projects and ensure that the underlying principles of soil management are not neglected when (for example) developing fertilizer recommendations.

The total annual cost of these constraints in terms of lost production in WA is estimated as $1680M (Herbert 2009); the GRDC investment to tackle these problems is $33M over five years.

GRDC recognize the importance of integrating projects that work on soil constraints, and in 2015 will launch a National Soil Constraints Initiative. This is described in the GRDC External Investment Plan 2015-6, and initially includes four projects with an indicative total annual budget of around $2.6M for each of five years. These are:

  • Co-ordination and communication
  • Management of non-wetting soils
  • Management of sodic and magnesic soils
  • Innovative approaches to managing subsoil acidity

The three technical projects in this National initiative overlap with those currently funded in the West. It will be important to avoid duplication of research effort, and maximize the value of trials, demonstrations and products for the benefit of industry, and to enhance the communication of information and practice change with industry.


GRDC Western Panel (particularly Darren Hughes and Peter Roberts) for establishing and supporting this initiative; Alex Murray and Tanya Robinson (GRDC Canberra); Julia Easton (GRDC Western Panel Research support officer); and Julianne Hill (RCSN coordinator).


  • GRDC Strategic R and D Plan. GRDC Website - Strategic Plan 2012
  • GRDC External Investment Plan 2015-6, 236pp. GRDC Website Investment Plan
  • Herbert 2009. Opportunity cost of land degradation hazard in the south-west agricultural region. Resource management technical report 349, DAFWA, Western Australia
  • Regional Cropping Solutions Network Annual Report 2013-4: Western Region. September 2014; GRDC
  • Report card on sustainable natural resource use in agriculture. September 2013; DAFWA. DAFWA Website Soil Constraints

GRDC Project code: DAW00236, DAW00242, DAW00243, DAW00244