Figure 1: Sampling soil for the Soil Quality Monitoring Program
www.soilquality.org.au provides a unique, interactive resource to the Australian grains industry on soil quality, including soil biology as well as soil chemistry and physics. The web site allows growers to benchmark their paddocks against values for their local catchment and region as well as against expert opinion. This information aids growers to determine if they are heading in the right direction with their systems and practices and supports growers to improve soil management practices. The Soil Quality Monitoring Program and the web site www.soilquality.org.au are expanding to include grainproducing areas across Australia. This will give growers across Australia access to regionally specific data on soil biological, chemical and physical constraints to production (table 1, figure 1). This will aid the Australian grains industry to make better management decisions.
Table 1: A selection of the biological, chemical and physical indicators of soil quality measured as part of the Soil Quality Monitoring Program. The indicators in the monitoring program have clear relationships with soil quality and have the potential to constrain production.
Type of soil property
Soil quality indicator
Relationship to soil quality and production
Biological
Total organic carbon
Plays a key role in nutrient cycling and can improve soil structure
Microbial biomass
Closely related to nutrient release from crop residues
Diseases & nematodes
Causes patches of poor growth in a range of crops
Molecular fingerprinting
A measure of which organisms are present to help unravel the complexity of soil biology
Potential soil nitrogen supply
Provides an index of the capacity for nitrogen release from soil
Chemical
pH
Affects nutrient availability, microbial activity, aluminium and manganese toxicity
Cation exchange capacity
Influences soil structure stability, nutrient availability and soil pH
Nutrients
Essential for plant growth; deficiencies limit yield
Physical
Bulk density
Affects root growth rate, water availability and susceptibility of crops to waterlogging
Required to convert soil quality indicators from ‘per kg’to ‘per ha’
The information on the website is provided in a number of formats including a ‘traffic light’ snap shot that highlights the main indicators of concern in each catchment and region (figure 2). The traffic light system is based on expert panel recommendations for critical values of each indicator housed in the web site. Growers can also benchmark their own soil quality results against that of other growers in their catchment and region (figure 3).
Figure 2: A ‘traffic light’ snap shot of soil quality. This shows the percentage of farms in a region where indicators of soil quality fall within the categories of red (high risk), amber (of concern) and green (low risk).
Figure 3: An example of a commercial site where the grower’s carbon stock (orange dot) is compared with the range for all the sites in the catchment or region. The range of the middle 50 % of sites in the catchment or region is shown by the green rectangle.
The soil quality data on the web site is supported with fact sheets and simple calculators. Fact sheets relate the soil quality indicators to productivity and management options. Simple calculators enable ‘what if’ scenarios to be tested to highlight management decisions that may improve soil quality.
Soil health workshops enable growers to understand and interpret the data being generated. Computer and web training shows growers how to access and examine their own data via the web site (figure 4). This training empowers growers to make better-informed management decisions with respect to production and longer-term soil sustainability.
Figure 4: Training workshop for growers on monitoring soil quality indicators and use of the web site www.soilquality.org.au
Prof Daniel Murphy
Dr Frances Hoyle
The National Soil Quality Monitoring Program is being funded by the Grains Research and Development Corporation, as part of the second Soil Biology Initiative.
The participating organisations accept no liability whatsoever by reason of negligence or otherwise arising from the use or release of this information or any part of it.