Summary

Soil acidity graphic

Soil acidification

~20%

of modified agricultural land in NSW (excluding rangelands) is at high risk of acidification

Tree in soil profile graphic

Loss of soil organic carbon

12.6%

of natural carbon stocks have been lost across NSW

While most soils are in a moderate condition, some parts of the State have suffered a greater decline in condition than others and display a significant loss in their ability to deliver ecosystem services.

Much of the change in soil condition has occurred over longer timeframes, largely reflecting historical losses due to the lack of knowledge earlier about managing soils sustainably in Australian conditions.

More recently, the increasing intensity of land use, climate variability and extreme weather events are greater risk factors in maintaining soil condition.

On a statewide level, the increasing acidification of agricultural soils due to the intensification of land use continues to be the land degradation issue that contributes most to ongoing declines in soil condition and productivity across NSW.

Other factors such as decline in soil organic carbon, salinisation and loss of topsoil due to hillslope and wind erosion are still of concern, but appear to be stable or decreasing in impact.

New conservation farming practices, such as maintenance of groundcover vegetation and reduced tillage, have helped to control erosion and maintain soil condition. The extent to which these practices improve the management of organic carbon levels and prevent acidification is less clear.

Related topics: Climate Change | Native Vegetation

NSW indicators

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Indicator and status Environmental 
trend
Information 
reliability
Soil pH (acidification)
statusMODERATE
Getting worse ✔✔
Organic carbon
statusMODERATE
Stable ✔✔
Hillslope erosion
statusMODERATE
Getting better ✔✔
Wind erosion
statusMODERATE
Getting better ✔✔
Salinisation
statusMODERATE
Stable ✔✔

Notes:

Terms and symbols used above are defined in How to use the report.

Context

Soils make a significant contribution to the economic prosperity and ecological integrity of the NSW environment. Healthy soils deliver essential ecosystem services, including:

  • nutrient transformation and cycling
  • water infiltration and filtering
  • climate regulation through carbon storage and cycling
  • providing habitat for biota
  • supporting natural ecosystems and
  • enabling farming for food and resources.

Soil is essentially a non-renewable resource, as its formation is an extremely slow process that is beyond human timeframes (Bui et al. 2010; DOA 2014; Stockmann et al. 2014). Therefore, to maintain productivity and ecosystem services, soils must be managed sustainably to prevent them becoming degraded.

The consequences of most types of soil degradation, such as soil loss from accelerated erosion, dryland salinity and subsoil acidity, are long-term and often irreversible, or, and costly to reverse. While some other forms of degradation, such as nutrient decline and surface soil acidification may be remediated if addressed early, restoration is often expensive (Lockwood et al. 2003). Applying best management practices can prevent or even reverse some lesser degradation processes in rural production landscapes.

Pressures

When European settlers first arrived in Australia they adopted traditional farming practices that had been developed for different soil and climate conditions in a different part of the world. Much of the soil degradation in NSW is historic in nature and had occurred before an understanding developed of how to manage soils sustainably in Australian conditions.

The development of modern land management systems such as conservation farming, pasture rotation and no-tillage, together with better maintenance of groundcover, have largely halted, and in some cases reversed, the decline in soil condition. However, there is still some way to go before best practice land management is being implemented consistently across the State.

While land management practices have generally improved, the pressure on soil condition continues due to the increasing intensity of land use across NSW. There is, therefore, a greater need to ensure that soils and land are managed sustainably and within their inherent physical capacity – i.e. according to their capability to handle a specific level of disturbance or use.

As part of the NSW Monitoring, Evaluation and Reporting Strategy program 2008–09, an assessment was made of the extent to which soils were being managed within their capability, described in (OEH 2014) and summarised in the 2015 SoE Report (EPA 2015).

The pressure on soil condition from different types of land uses across NSW and the levels of soil disturbance associated with them, is represented by the land disturbance index (LDI). This system assigns land use to one of six classes, from 1 for undisturbed land such as native vegetation reserves to 6 for intense cropping land (Gray et al 2015c; based on NCST 2009). Map 10.8 presents the change in LDI from approximately 2003–13, based on land use information collected by the NSW Government.

Map 10.8: Change in land disturbance index, approximately from 2003–2013
Map showing change in the land disturbance index over the last 10 years across NSW. Slight changes are evident in the central agricultural regions of NSW

Source:

OEH Science Division modelling 2017

An overall trend towards more intensive land use over recent years is revealed by the map, with a statewide increase in the LDI of 0.20 units (see Table 10.3).

Table 10.3: Change in land disturbance index (LDI) from approximately 2003-2013, by LLS region

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Local Land Service region

Change in land disturbance index (units)

Central Tablelands

0.29

Central West

0.40

Greater Sydney

0.08

Hunter

0.27

Murray

0.40

North Coast

0.35

North West

0.23

Northern Tablelands

0.27

Riverina

0.45

South East

0.20

Western

0.01

NSW

0.20

Source:

OEH Science Division modelling 2017

The LLS regions with the largest average increases are the Riverina, Central West and Murray (0.45, 0.40 and 0.40 units respectively). Many locations throughout the State, particularly in these three LLS regions have an increase of two LDI units, which for example, represents a change in land use from predominantly pasture to predominantly cropping.

However, some areas, particularly in the Western region, have changed to less intensive land uses, shown by the deep green in Map 10.8. These may, for example, reflect a change in land use from pastural lands to a protected conservation area. While a change in land management has occurred, a change in site conditions may not be evident immediately.

Although land use intensity may be increasing slightly across the State, as revealed by Map 10.8 and Table 10.3, land management practices may be improving simultaneously in many regions, to compensate.

For example, the Western region has a long history of wind erosion. The National Landcare Program and Catchment Action NSW have invested in changing land management practices on farms in this region, resulting in a 50% increase of sites with best management practices, from 16% in 2003, to 66% in 2016, as shown in Figure 10.3.

Figure 10.3: Trend in best management practices in the south-west of the Western LLS region, 2003–2016

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This chart is interactive - click on legend or hover over chart

0237 SOE Graphic Assets web-V3-MS

Source:

Leys et al. 2016

While soil may be managed sustainably with little risk of degradation during normal weather patterns, the unpredictability and variability of severe weather events can lead to conditions where the soil’s capacity to cope is suddenly exceeded, leading to loss of soil condition and degradation.

Climate change is expected to lead to more extreme weather events and generally drier conditions across much of NSW (Baldock et al. 2012; OEH 2015). This will increase the challenge in managing for weather variability and weather extremes such as high erosivity rainfall events, increased fire and drought. A changing climate will require a rethink of the way that soils and land are currently managed by geographic locations. Without adjustments, it is possible that land may be used beyond its capability.

Climate change will also increase the risk of some soil degradation hazards, particularly wind erosion and loss of soil carbon (Rengel 2011). For more information on the effects of climate change see the Climate Change topic of this report.

Rising population in urban areas and increased demand for food at various levels – local, regional, national and international, is leading to an intensification in the use of productive land and greater risk of soil degradation. At the urban fringe, highly productive land is coming under growing development pressure, while population loss from rural areas reduces the capacity to manage land effectively (see DECCW 2009).

Economic factors such as declining farm profitability, or poor international trading conditions, including surplus stocks of resources or high foreign exchange rates (as occurred in the recent past), may lead to the intensifying of land uses and production activities in order to maintain viability, which may not be sustainable over the longer term.

Increasing fuel prices and competition for essential resources like water and fertilisers are other significant factors that pose challenges for managing the land sustainably (Cribb 2010).

Responses

The Soil Conservation Act 1938 provides for the conservation of soil and water resources and the mitigation of erosion. Through this Act the Soil Conservation Service was established, a NSW Government-owned soil conservation and environmental consulting business.

The Local Land Services Act 2013 (amended in 2016) regulates the clearing of native vegetation on rural lands while the Biodiversity Conservation Act 2016 (BC Act) promotes conservation on private land. These laws aim to achieve a balance between land use and biodiversity conservation in NSW.

Clearing of native vegetation in urban areas and land zoned for environmental protection is regulated by State Environmental Planning Policy (Vegetation in Non-Rural Areas) 2017 (the Vegetation SEPP) as well as some provisions in the BC Act that provide for the biodiversity offsets scheme. For more information see the Native Vegetation topic.

The current approach to soil management in NSW is to consider soils as part of a broader approach to natural resource management rather than as a standalone issue (Webb et al. 2015). Specific policies for sustainable soil management in NSW include:

Landcare and other on-ground initiatives

Landcare is a community network that contributes to the integrated management of natural resources at the grass-roots level across NSW, including improved soil management and land remediation.

There are presently about 3,000 Landcare groups in NSW, who are working to:

  • reduce soil and streambank erosion
  • control weeds
  • revegetate river banks, farmland and other public lands.

Landcare groups also promote the sustainable use of soils through education and community awareness programs.

The NSW Government currently funds the Landcare program, including the NSW Local Landcare Coordinator Initiative, a four-year program running through to June 2019. This initiative involves 72 local Landcare Coordinators working with 34 organisations across NSW to build the capacity of the Landcare movement to achieve its goals of:

  • improving natural resources
  • encouraging sustainable agriculture
  • empowering the community to improve their local environment.

Local Land Services work with local communities, including Landcare groups and landholders, to develop strategies and programs to improve natural resource management and sustainable land use across NSW.

Catchment Action NSW is a NSW Government-funded program to deliver natural resource management priorities in the State, usually in conjunction with the National Landcare program. One high-level outcome is to protect or rehabilitate soils to support ecosystem services. This program is continuing in 2018–19.

Phase two of the National Landcare Program commenced in the second half of 2018.

The Emissions Reduction Fund (ERF) operates under the Carbon Farming Initiative Amendment Act 2014. The ERF provides funding through a reverse auction mechanism to enable land managers to be financially rewarded for sequestering carbon. The first round of auctions in early 2015 resulted in 47 million tonnes of CO2-e abatement (28 million tonnes of CO2-equivalent gases being contracted for sequestration and 19 million tonnes by other means).

Advisory bodies and instruments

The Natural Resources Commission provides independent advice to the NSW Government on how to most effectively manage natural resources to maintain production and conservation. It works with the State’s regional communities and other stakeholders to improve or maintain the health and productivity of landscapes across NSW.

The Australian Soil Network oversees soil research and development strategies and their implementation throughout Australia. It comprises representatives from Rural Research and Development Corporations, government agencies, CSIRO, the University sector, and is currently co-chaired by the NSW Government (Department of Primary Industries).

The National Committee on Soil and Terrain coordinates and provides advice on soil and land assessment standards and policy. National protocols for monitoring soil acidification and soil carbon have been published (Grealish et al. 2011).

The National Committee for Acid Sulfate Soils (NatCASS) is assisting the Commonwealth Department of Agriculture and Water Resources to develop guidelines on acid sulfate soil management issues that are not being adequately addressed in some jurisdictions, including:

  • the clean-up of groundwater in areas of acid sulfate soils
  • dredging of sulfidic sediments
  • managing mono-sulfidic black ooze accumulations.

NatCASS is also completing a Code of Practice for the re-use of ASS materials that are excavated and removed from development sites, and NSW is actively represented. Guidelines for the identification and management of inland ASS were developed through the National Water Quality Management Strategy (NWQMS) (Baldwin 2011)

The management of salinity throughout NSW is guided by NSW Water Resource Plans in combination with the Hydrogeological Landscape program.

Research, development and data collection

The National Soil Research, Development and Extension Strategy (DoA 2014) aims to conduct research that meets the needs of farmers and primary producers and provide information promoting sustainable soil use and management.

The NSW Office of Environment and Heritage (OEH) collects data on soil and land management processes, conducts surveys and maintains NSW soil data through eSPADE.

The NSW Department of Primary Industries (DPI Agriculture) has a large research and development program that develops technologies and management systems to:

  • maintain and enhance the physical, chemical and biological productivity of soils
  • protect soil resources,
  • build resilience and reduce environmental impacts.

It works in partnership with Local Land Services and private stakeholders to ensure research and development findings are delivered to industry.

Monitoring programs

The performance monitoring system of the Soil Health Evidence Based Assessment (SHEBA) program (formerly SoilWatch) is applied in many regions of NSW. It complements and supplements other surveillance monitoring.

The cross-agency collaborative Community DustWatch program has been monitoring the extent and magnitude of dust events across NSW for the past 10 years. NSW Government agencies also lead the national assessment of wind erosion (Leys et al. 2016) and the use of remote sensing to assess the extent of groundcover.

Under Phase 2 of the National Landcare Program, groundcover will be a key reporting indicator, with the reporting methods developed in NSW being proposed for use nationally.

References

Baldock JA, Wheeler I, McKenzie N & McBratney A 2012, ‘Soils and climate change: Potential impacts on carbon stocks and greenhouse gas emissions, and future research for Australian agriculture’, Crop and Pasture Science, 63, pp. 269–83 [dx.doi.org/10.1071/CP11170]

Baldwin D 2011, National guidance for the management of acid sulfate soils in inland aquatic ecosystems, Commonwealth Government, CSIRO, Canberra, EP101559

Bui EN, Hancock GJ, Chappell A & Gregory LJ 2010, Evaluation of tolerable erosion rates and time to critical topsoil loss in Australia, CSIRO, Canberra [nrmonline.nrm.gov.au/catalog/mql:2237]

Cribb J 2010, The Coming Famine: The global food crisis and what we can do to avoid it, University of California Press, Berkeley, California [https://www.ucpress.edu/book.php?isbn=9780520271234]

DECCW 2009, NSW State of the Environment Report 2009, Department of Environment, Climate Change and Water, Sydney [www.epa.nsw.gov.au/soe/soe2009]

DECCW 2010, NSW Climate Impact Profile: The impacts of climate change on the biophysical environment of New South Wales, Department of Environment, Climate Change and Water, Sydney [http://climatechange.environment.nsw.gov.au/Impacts-of-climate-change/2010-NSW-climate-impact-reporting]

DoA 2014, The National Soil Research, Development and Extension Strategy: Securing Australia’s soil for profitable industries and healthy landscapes, Commonwealth Department of Agriculture , Canberra [www.agriculture.gov.au/ag-farm-food/natural-resources/soils/national_soil_rd_and_e_strategy]

EPA 2015, NSW State of the Environment 2015, Environment Protection Authority, Sydney [www.epa.nsw.gov.au/about-us/publications-and-reports/state-of-the-environment/state-of-the-environment-2015]

Fenton G & Helyar KR 2007, ‘Soil acidification’, in Charman PEV & Murphy BW (eds), Soils: Their Properties and Management, Oxford University Press, Melbourne

Gray JM, Bishop TFA & Smith PL 2015a, ‘Digital mapping of pre-European soil carbon stocks and decline since clearing over New South Wales, Australia’, Soil Research 54 (1), pp. 49–63 [www.publish.csiro.au/view/journals/dsp_journals_pip_abstract_scholar1.cfm?nid=84&pip=SR14307]

Gray JM, Bishop TFA & Wilson BR 2015b, ‘Factors controlling soil organic carbon stocks with depth in eastern Australia’, Soil Science Society of America Journal 79, pp. 1,741–51 [https://dl.sciencesocieties.org/publications/sssaj/pdfs/79/6/1741 (PDF 1.1MB)]

Gray JM, Bishop TFA & Yang X 2015c, ‘Pragmatic models for the prediction and digital mapping of soil properties in eastern Australia’, Soil Research, 53, pp. 24–42 [www.publish.csiro.au/sr/pdf/SR13306 (PDF 2.2MB)]

Grealish G, Clifford D, Wilson P & Ringrose-Voase A 2011, National Soil Condition Monitoring for soil pH and soil carbon: Objectives, design, protocols, governance and reporting, a CSIRO Land and Water Science Report for Caring for our Country [http://www.clw.csiro.au/aclep/documents/CLW_Science_Report_0511.pdf (PDF 1.9MB)]

Hazelton P & Murphy BW 2007, Interpreting Soil Test Results. What do all the numbers mean?, CSIRO Publishing, Melbourne

Leys J, Heidenreich S, Koen T & Colson I 2016, DustWatch Network and Roadside Survey 2016, Report for contract WN00732, NSW Government, Local Land Services (Western), Sydney [http://western.lls.nsw.gov.au/__data/assets/pdf_file/0009/684963/Updated-DustWatch-Network-and-Roadside-Survey.pdf (PDF 0.6MB)]

Littleboy M, Young J & Raman J 2015, Climate change impacts on surface runoff and recharge to groundwater, Office of Environment & Heritage, Sydney [http://climatechange.environment.nsw.gov.au/Impacts-of-climate-change/Water-resources/Groundwater-recharge-and-surface-runoff]

Lockwood P, Wilson BR, Daniel H & Jones M 2003, Soil Acidification and Natural Resource Management: Directions for the Future, commissioned report for the NSW Acid Soil Action Program, Wagga Wagga [www.researchgate.net/publication/236736946]

McKenzie NJ & Dixon J 2006, Monitoring Soil Condition across Australia: Recommendations from the Expert Panels, National Land and Water Resources Audit, Canberra

McKenzie NJ, Hairsine PB, Gregory LJ, Austin J, Baldock JA, Webb MJ, Mewett J, Cresswell HP, Welti N & Thomas M 2017, Priorities for improving soil condition across Australia’s agricultural landscapes, Report prepared for the Australian Government Department of Agriculture and Water Resources, CSIRO, Canberra [https://publications.csiro.au/rpr/pub?pid=csiro:EP177962]

MDBA 2011, Acid Sulfate Soils in the Murray–Darling Basin, Murray Darling Basin Authority, Canberra [www.mdba.gov.au/sites/default/files/pubs/Acid-sulfate-soils-in-the-MDB.pdf (PDF 8.8MB)]

Metcalfe DJ & Bui EN 2017, Australia: State of the Environment 2016: Land, Independent report to the Australian Government Minister for the Environment and Energy, Australian Government Department of the Environment and Energy, Canberra [https://soe.environment.gov.au/sites/g/files/net806/f/soe2016-land-final-web.pdf?v=1492063205 (PDF 6.4MB)]

Murphy BW 2015, ‘Impact of soil organic matter on soil properties: A review with emphasis on Australian soils’, Soil Research 53, pp. 605–35

NCST 2009, Australian soil and land survey field handbook, 3rd edn, National Committee on Soil and Terrain, CSIRO Publishing, Melbourne

NSW Agriculture 1998, Policy for Sustainable Agriculture in NSW, NSW Agriculture, Orange [https://catalogue.nla.gov.au/Record/664493]

OEH 2014, Soil condition and land management in NSW: final results from the 2008–09 monitoring evaluation and reporting program, Technical report series, Office of Environment & Heritage, Sydney [www.environment.nsw.gov.au/soils/140389MERsoil.htm]

OEH 2015, New South Wales Climate Change Snapshot, AdaptNSW, Office of Environment & Heritage, Sydney [http://climatechange.environment.nsw.gov.au/Climate-projections-for-NSW/Climate-projections-for-your-region]

OEH 2017, Digital soil mapping of key soil properties over NSW, Technical Report, Office of Environment & Heritage, Sydney [https://datasets.seed.nsw.gov.au/dataset/digital-soil-maps-for-key-soil-properties-over-nsw]

Renard KG, Foster GR, Weesies GA, McCool DK & Yoder DC 1997, Predicting soil erosion by water: A guide to conservation planning with the Revised Universal Soil Loss Equation (RUSLE), Agricultural Handbook, vol. 703, US Department of Agriculture, Washington, DC, pp. 1–251

Rengel Z 2011, ‘Soil pH, soil health and climate change’, in Singh BP, Cowie AL & Chan KY (eds), Soil Health and Climate Change, Soil Biology vol.28, Springer-Verlag GmbH, Berlin, pp. 69–85 [dx.doi.org/10.1007/978-3-642-20256-8_4]

Stockmann U, Minasny B & McBratney AB 2014, ‘How fast does soil grow?’, Geoderma, 216, pp. 48–61 [dx.doi.org/10.1016/j.geoderma.2013.10.007]

Tulau M & Morand D 2013, Aspects of Quaternary geology, geomorphic history, stratigraphy, soils and hydrogeology in the Edward-Wakool channel system, with particular reference to the distribution of sulfidic channel sediments, Technical Report, NSW Office of Environment & Heritage, Sydney

Webb AA, Kelly GL & Dougherty WJ 2015, ‘Soil governance in the agricultural landscapes of New South Wales’, International Journal of Rural Law and Policy, Special edition 1, 2015 [http://epress.lib.uts.edu.au/journals/index.php/ijrlp/article/view/4169/5022]

Wilson BR, Koen TB, Barnes P, Ghosh S & King D 2011, ‘Soil carbon and related soil properties along a soil type and land-use intensity gradient, New South Wales, Australia’, Soil Use and Management, 27, pp. 437–47

Yang X, Gray J, Chapman C, Zhu Q, Tulau M & McInnes-Clarke S 2017, ‘Digital mapping of soil erodibility for water erosion in New South Wales, Australia’, Soil Research, 56(2), pp. 158–70 [www.publish.csiro.au/sr/sr17058]