Soil moisture monitoring network
The Natural Resources SAMDB soil moisture monitoring network provides land managers access to real-time and historical data to help make more informed farm management decisions.
Having an accurate picture of the amount of stored moisture within the soil profile allows land managers to better predict crop yields and fertiliser requirements, and assist in making more strategic management and marketing decisions.
More than 40 soil moisture probes are located throughout the South Australian Murray Darling Basin region. In most locations several probes are located across different soil types so land managers can access information applicable to their own circumstances.
The following tables show the location and representative soil type of soil moisture probes. Click on any probe to access the soil moisture data for that site, and check out the section below to find out how to interpret graphed information. Each page contains a detailed definition of the soil type to help land managers assess the relevance to their own farm.
Mallee Soil Moisture Probes
Upper Mallee / Riverland Soil Moisture Probes
Upper South East Soil Moisture Probes
Mount Lofty and Northern Ranges Soil Moisture Probes
How soil moisture and temperate data is collected
The length of each soil moisture probe is largely determined by the depth to stone at each site. In areas with minimal stone probes are generally 1-1.2m in length. Where rock is a significant factor probes are shorter, but with a minimum length of 40-50 cm long.
Each probe within the soil moisture monitoring network records soil moisture at 10cm intervals throughout the soil profile. Soil moisture is recorded as a percentage, 0% being no water present and 100% representing total saturation.
Soil temperature is recorded by sensors located throughout the probe. These sensors are capable of recording a range between -55°C and +70°C.
Soil moisture and temperature sensors record information from a 10cm (lateral) radius.
Information is recorded every 15 minutes and transmitted back to a central server every 60 minutes.
Interpreting Soil Moisture Graphs
Information recorded by soil moisture probes is automatically converted into a range of graphs to provide useful information to land managers. For each probe, you’ll find a page displaying summed, stacked and soil temperature graphs.
Figure 1 - Moorlands Flat – Loam over Calcrete Rubble summed chart (example only)
In the above chart, the summed trend line in black shows approximate plant available water (PAW) for a cereal plant. The red shaded area represents the crop lower limit (CLL) - the point where a cereal plant can no longer extract any more moisture from the soil profile.
The blue shade area represents drained upper limit (DUL), the point where the soil profile can no longer hold any more moisture and is considered to be at 100% saturation. The grey shaded area between these two points represents plant available water (PAW).
In the lower section of the summed chart, the green trend line represents cumulative annual rainfall and the blue trend line represents cumulative growing season rainfall.
Figure 2 - Moorlands Flat – Loam over Calcrete Rubble stacked chart (example only)
The stacked chart shows soil moisture levels at 10cm intervals within the soil profile. The highest sensor in the soil profile is represented at the top of the chart with the lowest sensor shown as the lowest trend line. Comparing the changes in each trend line level shows the infiltration of rainfall through the soil profile (represented by an upward movement in the trend) or the depth plant roots are drawing moisture from (represented by a decrease in moisture levels of the trend line).
Daily rainfall amounts are represented along the bottom axis.
Figure 3 - Moorlands Flat – Loam over Calcrete Rubble soil temperature chart (example only)
Soil temperature values fluctuate daily and throughout the year. The soil temperature chart shows the soil temperature value measured at 10cm and 20cm depths. Daily rainfall amounts are represented along the bottom axis.
When using soil moisture probe data to inform decision making, land managers need to consider other factors that may prevent crops from accessing water. These include physical barriers such as the presence of rock within the soil profile and chemical imbalances such as significant salinity or low or high pH.
Accessing more detailed data
Soil moisture and temperature data can be rearranged to display values in a host of different ways. Land holders interested in this can log into the SAMDB Soil Moisture Monitoring Network using the following log in details.
User Name: samdb
Most sites within the network have multiple probes representative of different soil types and even soil amelioration methods. To match your own soils with the most representative probe, you’re encouraged to determine the soil types on your farm.
Detailed representative soil profile data is available for more than 1100 sites across southern South Australia through Nature Maps, with a handy guide to using data sheets also available.
This project is supported by the SA Murray-Darling Basin Natural Resources Management Board through funding from the Australian Government’s National Landcare Programme and the NRM levies.