• Introduction
• Recent SMM observations
• Speedo assessments
• Speedo soil moisture graphs
  • Mallee
  • Wimmera
  • North Central
  • North East
  • Gippsland cropping
  • South West

The soil moisture monitoring 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 down to one metre as a reference point for a paddock.

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

No login or passwords are required, and speedos are automatically updated.

Figure 1: October rainfall deciles for Victoria

Decile 4 - 7 rainfall for the majority of the western half of the cropping areas in Victoria during October but there are also some districts with storm cells and isolated large rain totals at the end of the month. The North East cropping area was around average and the South West, northern country and Gippsland cropping areas were wetter at decile 8  to 10 for the month.

Figure 2: Rainfall totals for October

Crop responses were observed with rainfall above 25 millimetres. Areas with greater than 50 millimetres in this time period had freely available water that assisted wheat progress through grain fill.

Figure 3. Month to date (22 November) rainfall totals for Victoria

South of Bendigo and areas in east Wimmera are on track for above average November rainfall with greater than 50 millimetres recorded (month to date and further rain forecast). There was a significant storm centred on St Arnaud and around Charlton that contributed to these high totals. The South West has been drier.

Figure 4. Month to date (22 November) rainfall percentages for Victoria

St Arnaud has already received 200 per cent of monthly mean November rainfall and the nearby Charlton SMM site received > 50 millimetres of rain in the storm on November 3.  We observed rain infiltrate down to 60 centimetres at Charlton as an example of high rainfall impact on a ripe wheat crop

https://extensionaus.com.au/soilmoisturemonitoring/Charlton/

Further rain was forecast post this reporting period that could increase rainfall deciles in these areas.  

http://www.bom.gov.au/climate/maps/rainfall/?variable=rainfall&map=percent&period=cmonth®ion=vc&year=2021&month=11&day=21

Soil moisture measurements collected by the Agriculture Victoria monitoring network indicate very few monitoring sites increased their deep soil moisture levels in the past four weeks despite rain during October and November (see figure 3 - 4). Birchip (paddock in fallow - nothing growing) and Gippsland are the exceptions with positive deep soil moisture changes.

The spring rain provided some freely available water to crops through the grain-fill period and grain size is expected to be large which should contribute favourably to yield.

There is still a range of low to low/moderate soil moisture conditions in the Mallee and patches of the Wimmera.  There is evidence of potentially high yielding crops in parts of the Wimmera due to isolated storms during the growing season and more recently in the past three weeks. Large crop biomass with high yield potential has consumed a surprising amount of the paddocks soil moisture reserves. Mallee crops have dried off and no more rain is required.
North Central region crops have filled well with the cool finishing weather in October and crop water use was still observed in early November. Harvest has started and no more rain is required.
North East districts still have medium soil moisture levels, and the high yield potential crops were supported by rain during October and November that has provided freely available water. Canola harvest has started, and no more rain is required.
Some South West Victoria crops have been using high volumes of moisture, driven by high biomass and high yielding potentials and may require further rain to finish to potential.  Low lying areas are still very wet, and the Gippsland monitoring site is still wet at depth.

Note -  use extensionaus.com.au/soilmoisturemonitoring to monitor the changes to the sites relevant to you inbetween the next reporting period and following rain events

Werrimull stacked individual soil moisture graph – 2020/2021 view
The late sown wheat at Werrimull continued to deplete moisture from the whole profile but particularly at 70 to 80 centimetres in late September and early October as rainfall was not meeting crop water demands. In the district, early germinating barley is being harvested and no more rain is required.  November rain infiltrated down to 40 centimetres.

Ouyen stacked individual soil moisture graph – 2021 view

Wheat at the Ouyen monitoring site finished on October rainfall as this was enough to meet crop demands. Low to moderate residual moisture still exists at many depths. Rainfall in early November was enough to infiltrate down to 30 centimetres.

There has been some moisture depletion by the wheat crop at Speed and 18 per cent of the moisture profile was used in the last three weeks of October.  Rainfall in early November has paused this deep moisture depletion as the crop obtains the freely available water from the top horizon of soil and should benefit crop yield.

Some residual moisture has been left at depth after the vetch hay crop was cut in late September, effectively stopping crop water use.  Despite the rain since, there has been no moisture increase to rebuild soil profiles.

Deep soil moisture changes down to 70 centimetres at the medium/heavy soil type at Birchip. Paddock is in fallow and has an opportunity to allow greater moisture infiltration if there are further rain events as forecast.

The vetch crop was cut for hay in September.  Rainfall has been sufficient to provide a small increase to soil moisture conditions in the 30 - 50 centimetre zone. Surrounding grain crops would have utilised this rain.

Sheep Hills summed and stacked individual soil moisture graph – 2021 view

The crop being monitored is canola and is displaying high moisture requirements. All the moisture reserves built up over the winter were consumed during September and the crop was using residual moisture from the paddock history of vetch hay last year.  During late October, the canola was sourcing soil water from 90 - 100 centimetres and dried that zone down to levels not seen since 2015.

There was 30 per cent of moisture used in the past two months by the clover at the Taylors Lake site with additional rain providing ideal conditions for pasture production.

Moisture has moved down to 50 centimetres with a storm event on 3 November. There is enough moisture for grain fill in this district and paddocks are banking moisture for next season.

Elmore stacked individual soil moisture graph – 2021 view

The monitored canola crop flowered for seven weeks (from 16 August to 5 October) and experienced peak water use during this time. Moisture for pod-fill, was predominately accessed from rainfall and provided four weeks of freely available water for finishing this crop. Windrowed on 9 November, the crop is just days away from harvest.

Acknowledgment to Raywood Regen Ag group for this soil moisture site report from Central Victoria. Over the past seven weeks, the wheat crop has only depleted 10 per cent of the residual moisture as the cool wet spring has provided the moisture for the crop to progress through the end of flowering and grain fill.

Raywood soil moisture (30-100cm)

Despite good rain events through October and early November, this wheat crops water demands have been large as a high yield potential exists.  At times there has been evidence of wheat using moisture down at 1 metre. The crop has matured, and further rain will provide no benefit to the crop.

Youanmite stacked individual soil moisture graph – 2021 view

The wheat crop has been consuming large amounts of moisture in the past month at a range of depths. In early November, the roots were predominately using moisture from 70 - 90 centimetres as it was drying above this depth.  Rain on November 12 (which was predominately located in North East Victoria) has provided the moisture for finishing grain fill. Potential yield calculations were determined to be 5.2t/ha with 418 heads per metre, again showing high yield potential crops have very high water requirements and deep soil moisture reserves are critical.

https://extensionaus.com.au/soilmoisturemonitoring/crop-yield-calculator/

The Giffard West site still has a wet deep profile and some of the deeper sensors are saturated.  Shallow moisture starting to be used by the wheat.

Lake Bolac has used large amounts of sub-soil moisture in the past two months. Spring rain has had no impact with building soil moisture reserves, just pausing the depletion from the deeper root zones.  Inspection of the crop on 18 November identified a dense wheat crop with high water requirements. The long season wheat was still progressing through flowering and requiring more water to support filling the large heads. The soil profile when cored was confirmed as being dry to depth. Crop yield calculations determined there were 600 - 700 heads metre and heads up to 11 florets long, providing a potential yield of 8.2t/ha. It was still too early to determine the success of grain fill in all flowers.

https://extensionaus.com.au/soilmoisturemonitoring/crop-yield-calculator/

Canola at Hamilton has used 60 per cent from full in the past two months, progressing through flowering and pod fill.  During that time there has been rain supporting the crop production, but it has not met crop water requirements.  Some moderate deep soil moisture reserves exist.

Yalla-Y-Poora stacked individual soil moisture graph – 2021 view

A new commissioned site at Yalla-Y-Poora to validate an existing monitoring point reached field capacity numerous times during the year. The wheat crop accessed moisture down to 60 centimetres and rain on 12 November was still used by the crop for grain fill.

Crop yield calculator (using the GIAV app) for the 2021 crop tour. Crop density ok (wet year could have reduced tillering) head development good with head length consistently averaging 7 -– 8 florets long and filling 4 wide with up to 5 in places.  Yield estimate for the Beaufort wheat variety is 5.5 – 6.6 t/ha depending on final grain number and grain size.