• Introduction
• Weather and soil moisture monitoring observations
• Speedo assessments - change in overall soil moisture at a particular site.
• Speedo soil moisture graphs
  • Mallee
  • Wimmera
  • North Central
  • Northeast
  • Gippsland cropping
  • Southwest

The soil moisture monitoring (SMM) project, with the use of underground probes, provides real-time soil water content data to Victoria’s farmers.

Monitoring sites have been set up in cropping regions throughout the state by Agriculture Victoria.

The sites record soil water content at one source point from 30 centimetres (cm) down to 1 metre as a reference point for a paddock.

To access information provided in the graphs, log onto the Agriculture Victoria soil moisture monitoring dashboard.

No login or passwords required, and speedos are automatically updated and will represent the most recent rainfall.

Figure 1: July and August rainfall deciles for Victoria

The Victorian rainfall decile map for July and August demonstrates the drying trend in the second half of winter, with most of the state except parts of the Mallee below average rainfall.

Figure 2.  September rainfall totals (month to date) for Victoria

A dry start to September and cropping districts have had less than 25 mm and many districts in the northern country less than 10 mm.

Figure 3. September rainfall percentage (month to date - 18 September) for Victoria

Over much of the state has been drier. Recent and historical rainfall maps Parts of the northern country are less than 20% of rainfall and will likely be well below average (decile 1).

Soil moisture measurements collected by the Agriculture Victoria moisture probe network and focusing on the monitoring sites of cereals and oilseeds (excluding fallow and pulses) have soil profiles being rapidly depleted, but the very deep moisture still remains.

Wimmera, parts of the Mallee and some areas of central Victoria have moderate soil moisture levels, largely due to the very deep contribution of the sensor values at >70 cm.

As stated in the previous cropping report, areas with high yield potential crops and receiving less than 25 mm for August, started an early depletion of soil moisture reserves. Current drawdown of moisture through September would indicate the very deep soil moisture will be utilised. 

Further rain is required in all regions. Continuing dry conditions will gradually place moisture stress on crops and commence reduction in yield potentials.

East Gippsland has not been able to build soil moisture over the past month continuing to deplete limited moisture reserves.

Note - use extensionaus.com.au/soilmoisturemonitoring to activate your preferred reference monitoring location soil moisture percentage. 

Low population, low biomass crop of chickpeas grown at this site is a large factor with the deep soil moisture being 100%. Moisture reserves will remain until there is growth and plant demand that exceeds rainfall. 

During July, crop water requirements exceeded rainfall and moisture profiles started to be depleted at 30 – 60 cm. August rainfall was able to meet barley crop requirements and the rain in early September also delayed the depletion of moisture reserves.  Rain and the responses observed to monitoring soil moisture charts are positive signs for yield as the crop is accessing the easiest to source soil water.

Vetch was terminated at the end of August so there is expected to be no moisture used in this paddock. A full profile should be carried through to next season.

Speedo shows moisture profiles are 85% and in line with the low water use crop type growing at this site. Lentils are developing a biomass in September and in the absence of rainfall, are starting to use the shallow moisture. Cereal crops in the district would be growing in drier profiles.

Moisture conditions are the same compared to this time last year. This site has used small amounts of moisture over the past month.

Deep soil moisture conditions are great and 40% wetter than this time last year. Low water use crop growing at this site.

The high-water holding capacity soil (self-mulching clay) is very wet to depth and is providing a large contribution to the overall summed speedo value. After a failed canola crop due to the wet winter, the resown barley is quickly using some of the shallow moisture.

Deep soil moisture conditions are good at 87% and the paddock is in fallow to conserve the soil.

Canola has used 28% in the past month and typical of canola water use in spring, it has been consumed at most depths through the soil profile.

Canola has used 35% in the past month and typical of canola water use in spring, it has been consumed at most depths through the soil profile.

Image from 7 September. High biomass oat crop, grown on free draining soil that provides readily available water to crops.  

Modelled soil moisture at Elmore with the Soilwater app compared to moisture probe data. Substituted wheat for the oaten hay crop but is showing similar trends. High biomass crops are seeking additional moisture with the dry August and September.

Youanmite had a near full profile a month ago and was well set up for wheat yielding above average. The crop has used 40% moisture in the past month and will require more rain during spring.

Wheat growing at the Youanmite SMM site. Drawing upon comparison to moisture use in other years, in 2019, crop lower limit was confirmed and the crop finished grain-fill on deep soil moisture.

The straight lines come from the extrapolate tool on Intelligraph platform with current soil moisture use based on the past 4 days with similar weather and no rain. This function is traditionally used with irrigation environments to assist irrigation scheduling and refill points to provide readily available water to crops.

The Giffard West site in Gippsland is much drier than this time last year and there has been 12% moisture use in the past month. Canola flowering is contributing to the moisture depletion with small volumes of rain in September.

The Lake Bolac site is showing evidence of shallow to mid profile soil moisture use.

The dry start to spring has canola starting to use some of the stored soil moisture and 30% of the profile has been used in the past month.

In August there was evidence of the crop using some of the shallow stored soil moisture and the rain (Sept 5) provided water to the wheat for one week, before returning to moisture reserves.