• 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: Growing season rainfall deciles for Victoria (April - September)

The Victorian rainfall decile map for growing season rainfall (GSR) in winter cropping regions shows all cropping regions except for Gippsland are below average.

There are large areas of decile 1 and limited cropping areas above 200mm GSR.

Large parts of the mallee received less than 100mm for the period from April to the end of September, with crops reliant on stored soil moisture.

Figure 2. September rainfall totals and rainfall deciles

Southern parts of Victoria received average rainfall for September.

Most of the northern cropping regions received less than 25mm and that resulted in steadily depleting soil moisture reserves.

Crops that had biomass and capacity to extend the root systems into the soil profile used the water quicker (cereals) than crops like lentils.

The Mallee and northern Wimmera was decile 1 with less than 10mm for September.

The dry September on top of low GSR has reduced yield potential in Wimmera and Mallee districts.

Soil moisture measurements displayed on the Agriculture Victoria dashboard. The monitoring of cropping sites highlights the dry conditions experienced in the western side of the state.

Mallee, north-central, north-east and Wimmera cereal crops have no or very little plant available soil water remaining. The perennial pasture sites are still much drier than normal and has resulted in less winter catchment runoff water into catchment dams.

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

All sites soil moisture percentages 10 October including annual winter crop and non-cropped paddocks and perennial pastures.

The drop-down selection bar on bottom left-hand side of the map (highlighted in the red box) provides the option to either select crop or grazing sites.

Cropping sites are reviewed in more detail in the sections below.

The probe was replaced in the Werrimull district in March, and still requires calibration for this new soil type.

Moisture improvements that were observed in July were largely used by the barley crop in August.

The barley experienced moisture stress during September that has continued into early October, reducing yield expectations.

Barley at Werrimull has had limited access to moisture since the start of spring. Photo taken 30 September.

Lentils are growing at Ouyen and have depleted all the possible moisture reserves with this shallow rooted crop.

Higher water demand crops such as barley are likely to have lower soil moisture profiles.

Ouyen has recorded <25mm for the past three months and a large area of the region is decile 1.

Data back online in April. Wheat has used over half the available soil moisture in the past month.

Wheat growing at Speed monitoring site and utilising the deep soil moisture that was available at the start of September. Photo taken 5 October.

Canola has used 50% of the profile at Normanville in the past 10 weeks and during August it showed the typical characteristics of canola being aggressive in soil moisture use when the crop was in the stem elongation growth stage.

The crop has exhausted the shallow moisture (30 - 60cm) and recently it has all been deep moisture consumption in the absence of rainfall.

The barley crop has continued to deplete moisture reserves in the absences of rainfall to meet plant water requirements. In the past month, most soil water has been accessed from the deeper part of the soil profile from 70 – 100cm.

Barley crop on lentil stubble at Sheep Hills/Bangerang 16 September 2024. This crop was looking fresher than other cereals at the time with slower development due to a later sowing date.

Sheep Hills paired monitoring sites (Warracknabeal East Conservation Farming group) on 16 September 2024. Left is heavier soil type, with lentils, right is barley on canola stubble on a medium soil type with lower water holding capacity and showing signs of moisture stress.

16 September, Close up of the lentils with over 50% moisture still in profile and using shallow moisture.

Barley on the right has consumed most of the shallow moisture and doesnt appear to have the capacity to access the deeper moisture at 80cm.

Deep soil moisture is being access by the wheat crop and has consumed 45 percentage points of the profile in the last month. In the past week it has been using the moisture at 90 - 100cm as it appears this moisture stressed crop doesn’t have the capacity to dry other parts of the profile to wilting point.

Wheat crop at Brim 16 September 2024, showing signs of moisture stress and reduced grains per head potential.

The wheat crop was late emerging with a very dry autumn and has low biomass and yield potential due to lower starting soil moisture.

Summer moisture was depleted by the volunteer canola grown and grazed over January. The wheat does not appear to have the capacity to expand its root system into the deeper soil moisture at 80cm.

Late wheat crop development 17 September 2024 at Taylors Lake site and signs of moisture stress.

Barley rapidly used the shallow soil moisture reserves to meet crop water demands with high yield potential and is now using moisture at 80 - 100cm.  See link for October update. 

Lentils at Minyip 4 October, growing well on shallow moisture. Many lentil monitoring sites are only using moisture at 50 - 60cm. The soil core at this site showed one of the best root structure systems l have observed in hundreds of cores.

Lentils have not extracted moisture from depth after last year’s fallow and could be further investigated for potential constraints or if a true connection to this moisture has occurred. This soil type does have a very large water holding capacity above the first sensor positioned at 30cm. Soil classification indicates this soil can hold approximately 45 - 55mm plant available water in the top 30cm.

Modelled soil moisture at Birchip with the Soilwater app to simulate a cereal crop and moisture depletion in decile 1 season. With an estimated moderate/high plant available water at the start of April after a wet summer, wheat planting date of 1 June, the whole profile has been depleted.

This would have the assumption of appropriate biomass generated during winter and the model has been depleting moisture reserves from mid-July as rainfall was unable to meet crop water demands during this time.

Low September decile rainfall has not been able to meet wheat crop water requirements. 50% of the deep soil moisture reserves have been used in the past 6 weeks.

Early sown wheat crop at Coonooer Bridge, photo taken 4 October 2024 and wheat was progressing through flowering and was looking ok.

Latest update is the frost event on 8 - 9 October had a significant impact on grain yield expectations and the crop has now been cut for hay.

Local weather station data recorded temperatures below 0 for 5 hours and getting as low as -3.5 for 2 hours on 8 October 2024.

Low September decile rainfall has not been able to meet wheat crop water requirements. 60% of the deep soil moisture reserves have been used in the past 6 weeks showing that high yield potential crops need additional rain during spring to support crops through critical crop growth stages.

High yielding wheat is using moisture at 90 - 100cm and is expected to be accessing deeper reserves from summer rain that are below the moisture probe depth at 1 metre.

Modelled soil moisture at Elmore with the Soilwater app compared to moisture probe data. With an estimated moderate/high plant available water at the start of April to initialise the model it shows spring season moisture depletion and increasing biomass to be very similar to the probes. A longer probe would be beneficial at this site.

Offline - old probe unable to be fixed and new probe installed but needs calibration. While no probe data available, models like the SoilWater app can simulate crop growth and moisture use.

Canola is expected to have extended a root system deep into the profile and is aggressively depleting moisture from all parts of the profile. The crop being 10 days away from windrowing.

Increased crop growth is now starting to see moisture depletion from the reserves (see update). Rainfall is not meeting crop water demands

Lake Bolac is offline.

The wheat crop is using water reserves when rainfall doesn’t meet crop water requirements.

There have only been two rainfall periods when there has been moisture infiltration beyond the 30cm depth, and this has been shallow (60cm) so there are no deep moisture reserves available.

Limited rain in the past 8 months and no big daily totals so there have been no improvement to soil moisture reserves during the growing season.

Early sown red wheat is seeking access to limited moisture supplies but appears to be using water down at 1 metre.