Back to: Soil health for Victoria's agriculture - context, terminology and concepts
1.1 Background | 1.2 International context for soil health | 1.3 Soil health context in Victoria, Australia | 1.4 Developing a program for soil health in Victoria | 1.5 DSE, CMAs and soil health beyond agriculture
This report has been prepared for the State of Victoria’s Department of Primary Industries (DPI) project ‘Soil Health for Victoria’s Agriculture’ (MIS 07898). The project was funded for one year ending in June 2006 under the Agriculture Division’s key program 1.1 ‘Integrating Farming Systems into Landscapes’.
The foundation work of this project supports implementation of the DPI ‘Healthy Soils’ project1 (MIS 03250) which is funded under the Environmental Sustainability Action Statement (ESAS) until June 2010. The ‘Soil Health for Victoria’s Agriculture’ project had three partner agencies that provided co–funding:
Separate reports have been provided for the partner agencies.
The purpose of this report is to provide the Department of Primary Industries (DPI) and the Department of Sustainability and Environment (DSE) with sufficient science basis to support the development of priority actions for soil health. This report focuses largely on the primary production aspects of soil health for Victorian agriculture. Whilst this does include the environmental context for agriculture, a separate companion report for DSE has been prepared that more specifically describes the case for government investment in soil health issues beyond those concerned directly with agricultural productivity.
Soils are the fundamental agricultural resource, they are variable in the qualities they offer for agriculture and they differ in their requirements for management. There is considerable history of soils research in Victoria and Australia that has resulted in a knowledge legacy that is not readily available to agricultural practitioners, land management authorities and agricultural policy makers. Since the early days of soil conservation there have also been fundamental changes in government policies concerning land degradation, with an increasing emphasis on environmental monitoring and strategic planning for protection of land and water.
The management of soil for agricultural production has been fundamental to the survival and growth of human populations for the past 10,000 years. In the last century radical changes in agricultural practices have intensified the pressure on soil resources. Plant and animal improvement programs, increasing mechanisation, irrigation, artificial fertilizers and agrochemicals for weed and pathogen control have all contributed to higher production per unit area for the full range of foods and fibres produced from soil.
Concurrent with these changes in production systems there has been an unprecedented growth in human population globally and this has increased the pressure on soil and land resources to serve other needs. Competition for land resources has resulted in loss of high quality soils and potentially productive agricultural land to urban and infrastructure development, whilst expansion of agricultural and other human activities into the ‘natural’ environment has generated major concerns about ecological sustainability, the role of biodiversity, and the condition of rivers, lakes, groundwater and oceans. In many instances the soil resources themselves have deteriorated or become unproductive through, for example, erosion, salinisation, fertility decline, or contamination.
Global projections for human population food requirements by 2050 indicate that these will be at least double their present levels (FAOSTAT 1998). Given the limited availability of land and water, most of the increase in production will have to be met from existing soil and water resources or from marginal agricultural land. Pressure on the soil resource will therefore inevitably increase along with associated pressures on ecosystem services that are dependent on soil. As a major exporter of agricultural produce ($17.6 billion value annually according to the National Land and Water Resources assessment in 2001) Australia makes a significant contribution to global food security. The state of Victoria substantially supports this effort as well as providing national and global food security. Agricultural sector value of Victorian exports was estimated as $7.2 billion for 2001–2001 and $5.4 billion in 2003–2004 (this decline was attributed to drought and a high Australian dollar) (Business Victoria, 2005). The state government target is for an increase in agricultural export value to $12 billion by 2010. Achieving this target as well as maintaining or improving environmental quality depends on a thorough matching of soil and land
qualities to management practices and consequent pressures.
Soil is a critical ecological component that directly serves many ecological functions, supporting plant growth, absorbing and recycling nutrients, storing water, mediating as the interface between rainfall, runoff, interflow and recharge, and contributing to atmospheric regulation. In agro–ecosystems, soil is subject to greater change than in natural (non agricultural) ecosystems, the primary purpose in agroecosystems being to secure a carbon harvest in the form of food and fibre. Consequently, balances between inputs, outputs, storage and nutrient recycling are highly altered compared with natural systems.
Whilst there is a large body of specialised scientific knowledge to support management of soil in these systems, it is only recently that more holistic concepts embodied in terms such as ‘soil quality’ and ‘soil health’ have been seriously adopted in the scientific literature and have become part of the language of government policy. The topical nature of these terms, the mixed debate surrounding their meaning, and the urgent issues facing agriculture and the environment with respect to soil management, and the increased farmer interest in soil health, all provide timely context for this report.
This report and associated papers provide:
|1||The Department of Sustainability and Environment (DSE) paid for the preparation of a document defining the role of soil health beyond agricultural production, and the case for government investment.|
|2||West Gippsland Catchment Management Authority (WGCMA) commissioned land use impact assessment of current land use to assist in development of a soil erosion management plan.|
|3||North Central Catchment Management Authority (NCCMA) contracted the collation and review of the region’s soil and land data in preparation for strategic planning for the region’s soil health.|
1.2 International context for soil health
The leading global organisation in this area is the United Nations (UN). The UN has a history of investment in soil related issues through the Food and Agriculture Organisation and the United Nations Environmental Programme. Soil survey, land evaluation and soil conservation are the dominant themes in the work of the UN and FAO with soil quality and soil health implied rather than explicit. The FAO soils bulletins published since 1965 and the land and water bulletins published since 1995 contain substantial scientific knowledge and support for soil management. In particular, early publications on soil survey and land evaluation (FAO 1967, 1976) provided the context for more specialised advisory bulletins (FAO 1983, 1985), integrated land use planning (FAO 1995) and the use of indicators (FAO 1997). Many of these publications are available as electronic documents through the FAO web pages (external link). The FAO literature is largely directed towards less developed countries, focussing on extremes of degradation, issues affecting food and water security and using land within its capability.
The UN have also been important agents for policies concerning soil and land management; significant milestones being the World Soil Charter (FAO 1982), Agenda 21, and the United Nations Environmental Programme’s strategy for land use management and soil conservation (UNEP 2004). The latter proposed an ecosystem approach thus relating land and soil issues to other environmental focal areas and built on the 1982 World Soil Charter (FAO 1982) which had called for commitment by governments and international organisations to manage the land for long term advantage rather than short term expediency.
New Zealand has a significant history of work in soil quality and soil health. The 1991 Resource Management Act (RMA) Section 35 requires Regional Councils to report on the “life supporting capacity of soil” and whether current practices will meet the “foreseeable needs of future generations”. Protocols for monitoring land and soils were established in a six year trial commonly known as the ‘500 Soils Project’ (Sparling et al. 2004), and an interpretive framework for reporting at a regional scale was developed (Lilburne et al. 2004). The 500 soils project was evaluated by Hill et al. (2003) who recommended that seven soil quality properties (total C, total N, mineralisable N, pH, Olsen P, bulk density and macroporosity) validated in the work should form part of any soil quality monitoring programme. The requirements of the NZ RMA for reporting on soil quality at national and regional scales have parallels with Australian partnership agreements for NRM but, up to this point, there has not been the equivalent investment in monitoring Victorian soil condition. Lilburne et al. (2002) have described the strong relationship between legislation, policy and science for soil quality in New Zealand. The situation in Victoria, Australia, is such that legislation (the CaLP Act of 1994) and soil health policy (DPI 2006) are also aligning with funding to provide science to underpin implementation of that policy.
Recent developments in New Zealand have seen a rebirth of soil science in the form of a ‘Sustainable Land Use Research Initiative’ (SLURI), a national centre for maintaining and managing New Zealand’s soils (NZ Agencies 2004). This is effectively a collaborative venture devised by separate Commonwealth institutes (HortResearch, AgResearch, Crop and Food Research, and Landcare Research) in order to gain government support for soils research.
SLURI’s five priority areas for new science are:
- discussion of the national and international context for soil health,
- definitions for terminology associated with these more holistic paradigms for soil,
- descriptions and review of the science that underlies our current understanding of soil health,
- a summary analysis of Victorian soils data pertinent to soil health
- recommended priority actions for investing in soil health
Europe and the United Kingdom
The European Union (EU) adopted a European Soil Charter in 1972 and a revision of this charter was subsequently adopted in 2003 (Council of Europe 2003) in response to continued trends in soil loss and degradation and the need for a legal instrument across the member countries of the EU. In September 2006 the EU adopted a thematic Strategy for Soil Protection consisting of a Communication from the Commission to the other European Institutions, a proposal for a framework Directive (a European law), and an Impact Assessment (European Commission 2006a). Five technical working groups for the soil thematic strategy, comprising experts from the member countries, contributed background reports to the Commission in 2004. Reports from these groups on erosion, organic matter, contamination and land management, monitoring, and research are all available online (European Commission 2004; European Commission 2006b). Eight principal issues identified in this strategy are erosion, organic matter decline, contamination, salinisation, compaction, soil biodiversity loss, sealing2, landslides and flooding. One of the issues associated with soil sealing is a loss of soil diversity (pedodiversity) and this has led to proposals for soil types to be given equivalent conservation status as that given to species. The current scientific knowledge in the EU on soil biodiversity and its behaviour is regarded as too limited to allow for specific provisions in this Directive aiming at its protection.
In the United Kingdom, parallel initiatives have been developed for England and Wales, and for Scotland with strategies for soil quality or soil health being recently adopted (DEFRA 2004, SEPA 2006).
The Canadian Government have been active in the monitoring and management of soil health. Twenty-three benchmark sites were set up across Canada in 1989 to monitor soil quality under representative farming systems and landscape conditions. Measurements of key soil properties relating to land use and land management were made over several years and provided baseline data in 1995 for future monitoring. Results of the program were reported as a strategic framework for soil health in 1995 (Acton and Gregorich 1995). The report concluded that new government policy for soil conservation was needed, aimed at achieving sustainable agriculture and built on the understanding that agro–ecosystems are part of the broader environment. This reflects a change seen elsewhere in the world where, initially, soil conservation programs focussing on soil loss and erosion management have broadened in their approach. Acton and Gregorich (1995) also acknowledged the issue of scale and proposed that soil management programs are best designed at the farm level, integrating management practices to suit specific, local soil needs.
Within Canada, Alberta is the state that has shown the greatest uptake of the national strategy. Alberta has had a program of monitoring for soil health in place since 1997 and there is considerable documentation of this program available online (Alberta Government 2006). Key documents prepared recently in this program are:
|1||Intensification and Soil Functioning – Tools to ensure maintenance of soil services in the face of pressure from increasing inputs.|
|2||Managing Land–use Change – Provision of knowledge to assess the performance of land–uses now being carried out on soils not formerly used for these purposes, and the prediction of plant performance to express certain traits or qualities.|
|3||Resilience under Change – New system designs to sustain our existing land–uses in the face of the exigencies created by increasing climate variability and extreme weather events.|
|4||Valuing the Natural Capital of Soils – Research is required to assign value to the natural capital of our soils and waters to underpin rational land–use decision–making and resource allocation by industry and policy makers.|
|5||Landscape Designs – Tools are required to integrate and scale–up our understanding of enterprise and sector behaviours across the mosaic of land–uses to permit equitable resource allocation and sustainable coexistence of land uses.|
United States of America
Research and extension for soil quality and soil health have been prevalent in the United States since the early 1990s and much of the early literature on soil quality has its origins in the USA. Seminal publications such as those by the Soil Science Society of America (Doran and Jones 1996; Doran et al. 1996) provided the foundation for much of the language and approaches to soil quality and soil health adopted internationally. At the time of these publications, the United States Department of Agriculture (USDA) Soil Quality Institute produced a range of fact sheets and technical notes on soil quality that were widely available via the world wide web. Much of the work has been highly practical in nature and geared to the development of soil quality score cards and assessments for use on farm, with several of the states developing their own applications. A recent review by Wienhold, Andrews and Karlen (2004) emphasises the potential for a broadly based soil quality index.
1.3 Soil health context in Victoria, Australia
Soil protection in Victoria is historically based in soil erosion management and, subsequently, salinity. The work was led by the Soil Conservation Authority, later the Department of Conservation, Forests and Lands, and more recently the Department of Natural Resources and Environment. In 1991 the Victorian Office for the Commissioner of the Environment commissioned a substantial review of the impact of agriculture on the environment and identified a number of important soil issues (OCE 1991). The Department of Agriculture, its predecessors and successors (latterly NRE and now DPI) focussed on soil issues most affecting production (waterlogging, acidity, soil structure management) but has now taken up the lead for work on the more encompassing topic of soil health. During the development of the Victorian Catchment Indicators (Catchment and Water Division, 2001) program, a working group from government and University attempted the task of developing a soil health or soil quality index as suggested in the terms of reference provided by consultants for that project. Some progress was made towards this end but the proposed initial setup cost and ongoing monitoring costs were prohibitive within the budget of the funding division of NRE (Catchment and Water). There was also a lack of confidence in the ultimate value of such an exercise.
Recent impetus for soil health came from a government inquiry into soil acidity (ENRC 2004) and the government response to this inquiry (State of Victoria 2004) which led to development of a policy framework by DPI (DPI 2006). Planning for implementation of soil health work was carried out in parallel with the policy framework development and work commenced in the project reported here (Soil Health for Victoria’s Agriculture, MIS 07898).
1.4 Developing a program for soil health in Victoria
The primary reason for this current project is to assist in setting the foundation for a program of work supporting soil health in Victoria. This is given context by the framework for soil health written by DPI’s agricultural policy group (DPI 2006). The project team determined several purposes for an integrated soil health program. Such a program should:
- A description of site selection and sampling protocols for the Alberta benchmark sites (Cannon 2002).
- An extensive review by Winder (2003) describing 52 environmental/soil monitoring programs from around the world.
- A review synthesising literature on soil quality indices (current to December 2003) to inform recommendations for use in the Alberta Environmentally Sustainable Agriculture (AESA) Soil Quality Program (Hall 2003).
- A review of soil quality indicators with implications for Alberta’s agro–ecosystems (Bremer and Ellert 2004).
Analysis of current capacity to satisfy elements of the knowledge chain (Figure 11) was seen as the necessary foundation to begin with. A flow diagram to link some of the fundamental science work and audit of capacity required as a basis for the soil health program development is shown in Figure 1.
1.5 DSE, CMAs and soil health beyond agriculture
There is a broader interest in and responsibility for soil health that extends beyond the interests of primary producers. The principal difference between the interests of agriculture as a sector and of DPI, DSE and CMAs as governance bodies is one of scale. At the agricultural enterprise and paddock scale, the interest in soil health is specific to soil type and production system. Issues of soil fertility, pests and diseases, agronomic management and gross margins drive the implementation of activities directed towards improvement of soil health for a farm. At the governance (policy and planning) level, investment decisions in soil health have to resolve differences between public and private benefit, societal duty of care, and generational costs and benefits. Decisions are directed to strategic planning for whole sectors of agriculture and for large, sometimes national, regions. DSE as a co–investor in this project have been provided with a separate report (Boucher and Allinson 2006). Several CMA regions have embarked on soil health strategies although these are hampered by insufficient data on land condition. In two regions, modelling approaches have been adopted using DPI’s Land Use Impact Model (McNeill and MacEwan 2007). The LUIM outputs provide assessment of risks to soil health based on interpretation of soil susceptibility to degradation and assumptions about land management practices.
- Be the vehicle for enactment of government policy on soil health.
- Provide a blueprint for implementation of an integrated program of soil research, extension, adoption and improvement.
- Describe the accountabilities that relate to management of the soil resource (landholder, CMAs, DPI, DSE).
- Identify the partners and funding sources for delivery of elements of the program.
- Define CMA involvement in development and implementation.
- Develop an appropriate communication plan that provides a high profile for soil health and soil management.
- Assist in the requirements of government for environmental reporting (e.g. catchment condition).
- Provide a strategic assessment of the current agricultural landscapes in relation to soil health risks and needs. (Extent and severity of soil degradation issues such as acidity, and extent of major soil constraints to production).
- Consider potential impact of future changes in land use, land use practices, and climate on soil health.
- Describe the pathways to adoption of good soil management by the users of the soil resource.
- Support appropriate data management and information delivery for soils and soil health.
- Provide measures for soil quality and soil health that represent soil functional properties.
- Provide the means for comparison of soil quality and soil health across and within soil groups.
- Identify the opportunities in new technology and methods for understanding soil health.
- Identify research gaps that exist with regard to understanding soil quality and health in the context of different land uses or enterprises (industry forums). In particular, there is a need to define ‘sustainability rules’ for management of the soil resource in different contexts.
- Describe how future capacity (knowledge and skills) to support soil health R, D & E should be addressed.
Figure 1 Flow diagram illustrating components of work in developing and delivering a soil health program
Data analysis and evaluation
Data relevant to soil health are diverse and exist in a number of different forms. They are represented by the lozenge shaped blocks of the flow diagram in Figure 1, and have been numbered 1–6.
Crawford et al. (2006) have begun analysis of these data to:
|1||Soil point data (usually derived from auger or pit samples) have been collected as part of land resource assessment (LRA) projects and in the Reference Sites work funded previously by Agriculture Division (Mark Imhof’s work). Much of the data collected in these projects is stored digitally in the Victorian Soil Sites Database (VSSD).|
|2||Soil point data collected at research sites. At present there is no protocol for ensuring that such data become part of statewide datasets. If readily accessible these data should be entered into the VSSD.|
|3||Soil and land maps. These are polygonal data sets (spatial coverages at various scales) derived from interpretation of soil point data and other land attributes. These coverages are representative of soils and landforms across Victoria and, in some instances, have been interpreted in relation to land capability and potential for soil degradation. They are particularly useful for modelling or evaluating environmental risks if used in conjunction with land use practice information.|
|4||Land use data. Mapping of land use is currently being completed for regions of Victoria. Australian Bureau of Statistics (ABS) also provides data on land use and practices. These data can be used in modelling the potential impact of agriculture on soil health using the Land Use Impact Model (LUIM).|
|5||Remotely sensed imagery such as provided by Landsat is used to assist in developing items (3) and (4) but also has potential to be applied in monitoring soil health through plant performance (see Appendix B).|
|6||Productivity data from ABARE and ABS sources and projects such as the Land Monitor Project can be used in conjunction with land use and soil map data to assess the relative values and threats in current agricultural enterprise distribution.|
Provision of soil information for assessment and management of soil health
Extension of soils information consists largely of publication of reports related to soils research or soil and land survey, or to components of industry focussed projects such as Topcrop and Target10. As such, there is little information that provides an integrated view of soil health and soil management except in very general terms. A more focussed approach to soil health is needed because of significant regional differences in soils and the specific demands that different enterprises impose on soil quality. The ‘Healthy Soils’ project (MIS 03250) provides the opportunity to complete the delivery elements of the knowledge chain, through the project’s objectives which are to provide:
- Assess differences in inherent soil quality between major soils and regions.
- Model landscape opportunities and hazards with respect to soil health.
- Characterise Victoria’s agricultural landscapes and regions with respect to soil health.
- Determine suitability for purpose (for modelling, benchmarking and target setting).
- Identify gaps in coverages and in particular parameters that are necessary to determine soil quality.
- Improved access to available Soil Health information.
- Improved and new Soil Health assessment tools.
- Enhanced soil health extension programs.
- A coordinated Victorian program for Soil Health.