• 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: June rainfall deciles for Victoria

Majority of Victoria received average to above average rainfall in June but some areas of Gippsland and the Central Highlands were decile 10 and have full profiles.  Decile 8-9 rainfall areas in the Wimmera will help those districts establish crops and possibly build a small moisture profile. Generally average rainfall was enough to bring crop up and it could even be marginal on the heavier soil types.

Figure 2: June rainfall totals for Victoria

June rainfall in the Wimmera and Mallee was a turnaround from the dry Autumn which had created a dry moisture deficit on the top horizon. Greater than 50 millimetres will align up with areas with above rainfall for the month. Areas that were less than 50 millimetres will still require a month of above average rainfall to start to build a profile as late crops will require water to finish in spring.  Areas of 100 millimetres are wet, some are waterlogged and all these areas are at risk of greater water logging with further rain.

Figure 3. Month to date (21 July) rainfall totals for Victoria

The Wimmera and Mallee have 60-100 per cent of rainfall (month to date) and are on track for average rainfall for the month.  It has been dry in East Gippsland and wetter in the North East.

Figure 4. Soil moisture monitoring sites rated by quartile moisture per cent (new product development for the Ag Vic SMM dashboard)

Blue dots are sites above 75 per cent deep soil water storage and cover the South West and North East Victoria and Gippsland. There are areas in Central Victoria that are building nice moisture profiles for this time of year. Profiles are generally still low to medium in the Wimmera and Mallee, with previous hay rotations providing higher moisture values (green dots) than crops that went to grain in 2020.

Soil moisture measurements collected by the Agriculture Victoria monitoring network indicate low to medium soil moisture conditions in the Mallee and most parts of the Wimmera.  North Central and North East regions have had rain to generally have medium to high deep soil moisture levels and some areas are at or near saturation.

Gippsland received rain that has filled profiles in June but waterlogged low lying areas.  The majority of South West Victoria has rapidly filled soil profiles in the past six weeks.

Note - there are expected to be some changes to Speedos in the next 2 days so use extensionaus.com.au/soilmoisturemonitoring to identify the changes to the monitoring sites relevant to you.

The moisture profile at Werrimull has responded to July rainfall and now has some small levels of moisture infiltration being registered at 30-40 centimetres.  At this site there are still residual soil moisture from a low yielding oaten hay crop in 2020 that didn’t access all the available water and still some traces of water from the 50 millimetre thunderstorm on 1 January.

The Ouyen site has some small moisture improvements at 30 - 40 centimetres that will assist in connecting up the traces of soil moisture left from the vetch hay rotation last season. Cereal rotations in 2020 in this district would be drier than this monitoring site.

There have been some small moisture improvements at the site at Speed and will encourage the wheat crop to extend a root system to access the moisture banked from last year’s early terminated vetch crop.  Crop is late developing after a challenge to emerge in the autumn, so biomass is low and water requirements small at this stage.

There have been some positive moisture improvements at this site with over 50 millimetres in June. Oaten hay at the Normanville site last season left some moisture at 80 centimetres but is separated by a dry profile in-between.  Low water requirements for July and August are expected by the vetch crop and with further rain, the moisture percentage should improve.  Site was validated recently and confirmed that new seasons moisture has reached 40  centimetres.

Site was validated recently and confirmed that new seasons moisture has reached 40 - 50 centimetres.

No deep soil moisture changes at the medium/heavy soil type at Birchip.

Moisture has managed to move down to 30 centimetres in June but the vetch has a low water requirement at this time of year, assisting water movement down as a limited moisture deficit has been generated.

The speedo graph shows no deep moisture changes in the past month but on 16 June, 25 millimetres of rain was great to ensure germination of crops in the area. The paddock is a late sown canola crop and although water requirements are low now, they will increase in mid August onwards

There have been some good soil moisture improvements in the past month on this heavy grey vertosol soil at Taylors Lake and over 50 millimetres for June. This paddock has gone back into pasture and recently germinated clover will have a low water requirement until biomass develops.

The Coonooer Bridge site has continued some deep moisture improvements during winter that connected up moisture deposited from last year’s fallow, summer storms and rain in March. Further rain would be welcome to continue to fill moisture reserves that the high biomass wheat crop will seek in spring.

The Coonooer bridge site had soil moisture conditions validated recently and moisture was clearly identified to 50 centimetres and confirmed accuracy with the sensor readings. Moisture was present below this but decreased with depth.  Wheat was at first node growth stage and plant water demands will be increasing from this point on.

The Elmore monitoring site had the largest soil moisture improvements in autumn for the Agriculture Victoria network, conditions have remained wet over June and July and continued to build the deep water reserves.  While this site does experience some preferential flow of water down the side of the probe after rain, it is expected that the profile will be around 75 - 85 per cent with just the 80 - 100 centimetre zone to fill up (highlighted in red).

The Agriculture Victoria SMM site at Raywood is currently offline with a broken down modem.  On 22 June, when the modem was retrieved, the site was validated and physical examination of the soil would have the site similar, if not wetter than that these readings.

Ants have unfortunately gained access into the logger box of the Raywood field unit and damaged the modem. The monitoring devices have worked reliably right from the commissioning of the site until this incident and the original 12v battery is still functioning after 10 years. While the upfront costs of equipment are large, they can be divided by years of service, with each year’s data set increasing in value, we will keenly replace this old modem with a 4G system to monitor the current wheat crop.

Youanmite stacked individual soil moisture graph – 2020/21 view

All the individual soil moisture traces have capacitance values that have hit their maximum value or 100 per cent.  During the past month the deep sensors at 90 and 100 centimetres have reached field capacity.

The Giffard West site still has a wet deep profile.

Lake Bolac has had a large increase in winter soil moisture with significant moisture improvement in the past month and now has all sensor values at field capacity or 100 per cent full.

Hamilton SMM site is now back on-line after repairs to the communication system although rainfall is still not being recorded. The Hamilton site has also registered a large winter increase in soil moisture. Conditions are wet, saturated values at 30 - 60 centimetres combined with near field capacity values at 70 centimetres and deeper provide total values that make 100 percent.  Water logging is likely with further rain in this high rainfall zone.

Yalla-Y-Poora is offline until data is validated.  Another probe has been installed to compare the moisture conditions and will be monitored over the winter.