Forward this email | View in web browser
Soil Moisture Monitoring
14 April 2021
2021 Issue 2
In this edition:

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.

Sites monitored include: Werrimul, Ouyen, Speed, Kerang, Birchip, Normanville, Lah, Bangerang, Taylors Lake, Coonooer Bridge, Raywood, Elmore, Youanmite, Hamilton, Lake Bolac, Tatyoon, and Sale.
Locations of Agriculture Victoria soil moisture monitoring sites

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.

Victorian rainfall deciles for summer.

Figure 1: Summer rainfall deciles for Victoria

Rainfall during summer 2020–2021 was above average for the state as a whole, owing to a wetter than average January. Isolating some of the districts, the northern Wimmera and parts of the Mallee were below average.  It generally requires above average rainfall for summer to improve deep soil moisture conditions, but it can depend on the timing (late summer) and intensity of rain, i.e. >50 millimetres in a single event, to make an impact with the moisture probes.

Victoria rainfall deciles for January

Figure 2: March rainfall deciles for Victoria

Rainfall deciles for March are mostly average to below average in the Wimmera and Mallee but rainfall improved in regions to the East. Areas of decile 10 will have "banked” varying amounts of deep soil moisture for this year’s winter crop program which is explained in this report. Areas with an above average March rainfall, following a wet January, will start the season with a sound base of good soil moisture if timely weed control has been implemented.

Month rainfall totals for March (month to date). Rainfall was concentrated to North East Victoria and East Gippsland with rainfall on 23 March..

Figure 3. March rainfall totals for Victoria

Rainfall was concentrated to Central and North East Victoria and East Gippsland with storms in the second half of March. Moisture infiltration was observed with >50 millimetres of rain and no changes with sites receiving <25 millimetres.

Rainfall totals exceeding 100 millimetres at monitoring sites in East Gippsland has dramatically improved the soil moisture profile and the pasture sites at Bairnsdale. You can read more detail online

AWRA soil moisture map of Victoria from 9 April. A drop pin location at minyip for a wimmera reference.

Figure 4: AWRA modelled soil moisture

The AWRA model is a good indicator of recent rainfall and soil moisture conditions. A dropped pin location has been selected for the district of Minyip that had a positive response to the 29 January rain and if summer weeds were controlled, then most of this deep moisture would be available. The AWRA model assumes that after rain, vegetation will consume the plant available water which is why it has returned to a low value.

For more information go to Bureau of Meterology website landscape page  then select more information under the section - root zone soil moisture.

Speedo assessments

Soil moisture measurements collected by the Agriculture Victoria monitoring network show a wide range of conditions. After below average summer rainfall in parts of the cropping regions, some Victorian districts have had an early break in autumn.

The Mallee has generally missed any significant rain in the past four months and most monitoring sites are at similar moisture levels to harvest time last year.  The long data set of monitoring shows that sites with even average summer rainfall will not build up soil moisture reserves.
The exception in the Mallee was observed at Werrimull where parts of the Millewa received 50 millimetres on 2 January and on sandy soil this water moved deep into the profile but this rain was not widespread.  In the past month, this area has shown evidence of drying out on top due to heat and no rain.  History shows that until this deeper moisture is connected up with new moisture (i.e., a break), it won’t be available as the dry soil band restricts root exploration. 

The Wimmera missed the March rain, and the region is dry on top and still seeking a break for the season. However, areas around Minyip will still have deep soil moisture reserves due to good rain in January.  There are some areas in this region that have missed the summer storms completely and are at moisture levels similar to those recorded at harvest time. Hay or grain paddock rotations will have an influence on the current moisture level.

Most areas of North Central and North East Victoria have good soil moisture and many farmers have had the autumn break.

Note - Some of the soil moisture monitoring speedos below have been temperature adjusted to better reflect the current moisture conditions.

Soil moisture speedos at 9 April 2021
Speedo soil moisture graphs
Werrimull soil moisture (30-100cm)
Werrimull Speedo, moisture currently 80%

The moisture profile was about 50 per cent at the start of this year after an oaten hay crop last year. Following a storm cell on 2 January, the profile was wet. In the past month, with no rain and warm conditions, some moisture loss has been measured in the sensors closest to the surface.  This is a fine sandy soil site, positioned on a mid-slope and the lowest water holding capacity of the Agriculture Victoria network. Refer to Soils description on Extensionaus for site information details.

Ouyen soil moisture (30-100cm)
Ouyen soil moisture is currently 30 per cent.

The Ouyen site has slightly more moisture than this time last year, but this is due to the vetch crop cut for hay on 3 September. Below average summer rainfall has meant no moisture changes at this site.

Speed soil moisture (30-100cm)
Speed speedo showing 70%

There have been no moisture improvements for summer/autumn at the site at Speed.  Current soil moisture levels (which are temperature compensated) are high due to no moisture use in spring with early terminated vetch last year.  Other cereal crops nearby would have a lower moisture status.

Normanville soil moisture (30-100cm)
Normanville speedo moisture currently 40%

There have been no deep moisture improvements over summer and early autumn at this site. Oaten hay at the Normanville site used the shallow to medium depth moisture last year but the deeper moisture still exists. This is a common occurrence with hay crops.

Birchip soil moisture (30-100cm)
Birchip speedos moisture currently 30%
Brim soil moisture (30-100cm)
Brim speedo moisture currently 30%
Sheep Hills soil moisture (30-100cm)
Sheep Hills speedo 48 per cent

The temperature compensated speedo graph shows no moisture changes in the past month. It has a vetch hay background from last year and cereal crops in the district would likely be drier.  Sites south of Sheep Hills, e.g. Minyip have had above average summer rainfall and these sites still retain this deep moisture.

Taylors Lake soil moisture (30-100cm)
Taylors Lake speedo soil moisture currently 29%

The temperature compensated speedo graph shows no soil moisture changes in the past month on the grey self-mulching soil at Taylors Lake.

North Central
Coonooer Bridge soil moisture (30-100cm)
Coonooer Bridge soil moisture speedo at 70%.

The Coonooer Bridge site has had no moisture improvements in March and 25 millimetres of rain for the month was absorbed in the top horizon and failed to reach the 30 centimetre sensor.

Elmore soil moisture (30-100cm)
Elmore speedo current soil moisture 34%
Summed soil moisture graph from Elmore showing moisture improvement from 23 March.

This is a clay loam soil with 30-45 per cent silt.  Rain on 29 January had some positive impacts with soil moisture and this was followed up by the rain on 23 March which has gone down 40-50 centimetres.

Examples from the soil water app showing very similar conditions (modelled) to the ag vic smm probe data. Range of 29 per cent.

Report generated from the Soilwater app (smart device app that models soil moisture conditions) with the local soil type. The Agriculture Victoria soil moisture probe is 35 per cent and the model is 29 per cent, showing similar responses to the January and March rain events.

Raywood soil moisture (30-100cm)
Raywood speedos current soil moisture 100%

The Agriculture Victoria SMM site at Raywood had autumn breaking rains on 23 March with 50 millimetres which has kept the soil moisture profile topped up after a wet January.

Additional smm data from Raywood has this site at 40 per cent after recent moisture use from volunteer wheat.

This monitoring site north of Raywood is part of the North Central Catchment Management Authority - Regen Ag program and shows the influence of 75 millimetres of rain that has infiltrated down to 50 centimetres during January.  This promoted the growth of volunteer wheat which has been grazed by lambs, but as dry matter was produced, the soil moisture has been depleted by 30-40 per cent.  A large moisture deficit was generated, and breaking rains on 23 March were absorbed in the top horizon of soil and failed to infiltrate to 30 centimetres.

Two more monitoring points in the Raywood district showing sites are above 90 per cent moisture.

Soil moisture data is from the Raywood Regen Ag program with a paired site in the district of Neilborough growing wheat and barley last year.  Sixty  millimetres of rain on 23 March provided further moisture movement into the profile and connected to residual moisture left over from last year’s crops.  Thank you to the Regen Ag group for the data and displaying the benefits that a network spread through a district can provide.  These sites are also shown on the SMM dashboard.

North East
Youanmite soil moisture (30-100cm)
Youanmite speedo moisture currently 95%
Youanmite individual sensor soil moisture graph has had soil moisture improvements on 23 March..

Youanmite stacked individual soil moisture graph – 2021 view

Sixty millimetres of rain on 23 March has continued to build up the moisture profile, raising the cropping confidence in the region. Moisture improvements have predominately been at the 40–70 centimetre zone and below that is still wet from residual moisture carryover from 2020.

Tungamah soil moisture graph also has soil moisture improvements from 23 March rain.

Tungamah stacked individual soil moisture graph – 2021 view (source Riverine Plains)

Similar to the AgVic soil moisture monitoring site, rain in March has had similar impacts with moisture moving down to 60-80 centimetres. The aqua line at 100 centimetres is still at the same value through summer.

See the Weather Plus website for more information. 

Gippsland cropping
Gippsland (Giffard) soil moisture (30-100cm)
Gippsland speedo moisture currently 85 per cent

The Giffard West site has improved 50 per cent in the last month with rain totalling approximately 130 mm.

Giffard West monitoring site with summed and individual sensor trace graphs.  Site is wet after 130mm rain in March.

A multi-species pasture has been sown in this paddock and established well with emergence in January. Prior to the rain, there was evidence of root development accessing some mid profile moisture. The 125 mm of rain on 23 March will set up some excellent autumn feed.  Options are to graze through spring or terminate for spring sown wheat.

South West
Lake Bolac SMM (30-100cm)
Lk Bolac (pasture) soil moisture levels at 10 per cent

Lake Bolac has had no moisture improvements this year.

Hamilton soil moisture (30-100cm)

Hamilton is offline until repairs to rain gauge and communication system can be performed.

Yalla-Y-Poora soil moisture (30-100cm)

Yalla-Y-Poora is offline until repairs to soil moisture probe can be performed.


Privacy | Email:


If you would like to subscribe to the Soil Moisture Monitoring newsletter or find out more information, visit the Agriculture Victoria website

This newsletter is distributed by the Department of Jobs, Precincts and Regions.