Monitoring the condition of the soil resource

Wind erosion is a major threat to Australia’s soil assets. In some areas soils may be eroding faster than they are being formed. With increasing pressure on agricultural land to produce more food and fibre for a growing population, the drier marginal lands will be more vulnerable to wind erosion. At the same time, the area affected by moderate or severe wind erosion (currently 17 per cent or nearly 130 million hectares of Australia) is likely to expand due to increased drought and climate variability associated with climate change. The frequency of major dust storms, such as those experienced in eastern Australia in September 2009, is likely to increase.

Improving land management practices, especially those that improve ground cover management in the cropping, grazing and horticulture industries, will help reduce wind erosion and conserve the soil asset. Practices such as reduced tillage and stubble retention improve ground and vegetation cover, which in turn holds soil in place, protecting it from the force of the wind. These practices will also reduce off–site costs associated with dust storms, including respiratory health costs, disruptions to electricity supplies and aviation, cleaning costs, water quality decline and changes to global climate.

Caring for our Country is contributing funds to Dustwatch, a community research project to monitor dust transport and wind erosion across Australia, by expanding the network of community Dustwatch sites. DustWatch volunteers contribute local knowledge and scientific observations of dust activity, and this information is combined with data from satellite imagery, meteorological records, monitoring equipment and models to produce detailed maps of regional–scale wind erosion. The involvement of local communities in scientific research has proved a valuable way to improve research data and enhance community awareness of wind erosion in dust–prone areas of Australia.

Caring for our Country has also funded the development of Wind Erosion Histories which provide a wind erosion record for locations within natural resource management regions across Australia, from 1960 to 2008.

Dust levels can be monitored and reported hourly, daily, weekly or annually at site, regional, state and national levels, and are a cost effective and easily understood indicator of wind erosion.

Monitoring and reporting on wind erosion fact sheet

Wind erosion histories, model input data and community – DustWatch final report

Other work funded by Caring for our Country to help develop an integrated approach to wind erosion monitoring includes:

Improving the capacity to monitor wind and water erosion: a review

Computational Environmental Management System (CEMSYS) modelled wind erosion

Dust Sentinel Pilot: Capacity of three polar orbiting satellite instruments to map dust aerosol over the Australian continent

Manual of proposed national minimum standards for roadside erosion survey

Water erosion processes include hillslope erosion, gully and riverbank erosion. These are natural processes which are generally more severe in landscapes with high rainfall intensity, steep slopes and extensive bare ground.

Caring for our Country has invested in an examination of the options for future monitoring of water erosion.

• CSIRO/Caring for our Country report: Evaluation of Tolerable Erosion Rates and Time to Critical Topsoil Loss in Australia

The department is investing in improving the monitoring of ground cover. Spatially explicit monthly ground cover data are needed to improve modelling and monitoring of wind and water erosion, soil carbon and soil acidification. A workshop in November 2009 agreed on a national approach to ground cover mapping. The project aims to automate a satellite (remotely sensed) method of monitoring the extent of bare ground, green vegetation and dry or dead vegetation (which has an important role in providing ground cover) across Australia. A national network of ground reference sites will also be identified to validate this product. Led by the Australian Bureau of Agriculture, Resource Economics and Sciences, the project is being undertaken collaboratively with the department, CSIRO, the Terrestrial Ecosystem Research Network’s (TERN) AusCover project, Geosciences Australia and state and territory agencies. For further information, view the report through the link below.

Ground cover monitoring for Australia – establishing a nationally coordinated approach to ground cover mapping

Ground cover monitoring for Australia factsheet

Storing carbon in soil helps improve the soil’s structural stability, water retention and nutrient status. Increasing soil carbon will benefit farm production systems, and the landscapes in which farms operate.

Plants naturally sequester carbon through their photosynthetic processes. Soil carbon content in turn positively influences water holding capacity, nutrient availability and soil structure– all of which affect crop and pasture yields.

Management practices that can help increase soil carbon content by increasing the amount of organic (living) plant matter using the soil, while maintaining an economically viable farm business, may include:

• increasing the proportion of perennial vegetation in pastures, particularly in regions with significant summer rainfall where annual crops are being grown
• conversion to native vegetation of paddocks or portions of paddocks that show a repeated poor history of perennial vegetation growth
• increasing ground cover retention through maintaining crop residues
• careful management of stocking rates and increased use of green manure crops
• optimising farm management inputs to maximise water use efficiency.

Caring for our Country is investing in encouraging the adoption of management practices to increase soil carbon storage. Caring for our Country has also invested in the development of methods for monitoring carbon across Australia. For more information, view the report Building a foundation for soil condition assessment.

Soil pH (the acidity or alkalinity of soil) plays a significant role in nutrient availability for plant growth. Acidified soils – defined as soils with a pH reading below 5.5 – can increase the risk of permanent loss of nutrients and minerals; prolonged acidification of the subsoil is very difficult to reverse. Soil acidification is a natural process which is accelerated when land is managed poorly, and can result in significant losses to production. Acidification can change the balance of nutrients available to plants and result in establishment failure, increase in plant disease and poor plant growth (Charman and Murphy, 1991). For example, according to the Department of Agriculture and Food, Western Australia, acidification throughout the WA wheatbelt results in production losses of about $300–400 million annually (9 per cent of the crop).

Soil acidification can arise from leaching of nitrate (from legume or fertiliser origin) below the root zone or the decline of alkalinity through the harvesting of crop and livestock products. Practices that help reduce these impacts include regular soil pH and nutrient testing and liming, reducing the amount of acid substances applied directly to soils, balancing these with basic substances such as lime, or maintaining organic residues.

Caring for our Country has invested in the development of methods for monitoring pH across Australia. For more information, view the report Building a foundation for soil condition assessment.