• 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: August rainfall deciles for Victoria

August rainfall in cropping areas of southwest Victoria, the northeast and the districts linked to the Murray River border were below average.

Other regions range from average or just below. The central Gippsland region was decile 1.

Figure 2. August rainfall for Victoria

The northern Mallee and districts near the Murray River border had <25 mm for August and this is creating a moisture deficit in the topsoil horizon.

The largest moisture deficit site in August was at Giffard in Gippsland with <20mm for the month.

South Wimmera received >50mm for the third month in a row.

The North Central and Wimmera districts welcomed the rain at the end of August which generated monthly totals around decile 4 – 7.

Figure 3. Growing season (season to date April - end of August) rainfall deciles

Many cropping areas are below average growing season rainfall (season to date, end of August).

West Wimmera and the districts that received the autumn break rain on Anzac Day are the areas that are still tracking as average.

Soil moisture measurements displayed on the Agriculture Victoria dashboard.

The monitoring of pasture sites shows the improving conditions in the southwest.
Some areas remain drier than usual in west Gippsland.

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

All sites soil moisture percentages 1 September including annual winter crop and non-cropped paddocks and perennial pastures.

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

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

The Crop Plant Density tool is a simple method to calculate key crop metrics from crop observations in the paddock.

The formula remains the same, whether calculating plants or tillers so the opportunity to understand the crop biomass can be identified by entering the tiller counts into the relevant sections.

Knowing plant numbers and the development of tillers can show potential yield and also provide guidance with the hay versus grain calculation.

Find the crop density calculator on the soil moisture dashboard and save it to your smart phone home page to help determine crop biomass with paddock counts.

September is the ideal time to initiate crop yield estimations and support farmers with establishing crop protection insurance.

Tillers can be assessed, and early indications of head size can be conducted. Tillers can be reviewed in October to determine the number that progressed to successfully develop heads.

Barley in this photo (below) at the Normanville monitoring site has 13 grains both sides, so the half head count is 13.

This half head grain count is repeated 6 times across the paddock to gain a good representation of the stems (that were counted) and the heads they are supporting.

Half head counts on this barley is 13. 

Commissioned in autumn 2024 and currently being calibrated.

Small evidence of moisture improvement at 20cm during July, but decile 5 rainfall in August was not enough to build moisture reserves despite the very low plant water requirements of a low biomass crop.

Wheat continued to deplete more moisture reserves during August (23%) and this deep moisture use was initiated in mid-winter.

This demonstrates yield potential with increasing biomass providing rainfall meets or exceeds plant water requirements during September.

Limited soil moisture changes at Speed with low water demand crop of lentils growing.

Barley dry sown and emerged soon after the Anzac Day rain. Good yield potential and 15% moisture use during August.

Soil cores sampled 19 August matched the moisture profile displayed by the probes.

There has limited moisture changes at Brim, as a result of barley with low biomass and water demands and 30mm rainfall for August.

Note - fault in the sensor at 90cm.

Photo of the Brim SMM site 5 August with barley crop that emerged after King's Birthday weekend.

These late developing crops have not grown the biomass todate and the water use is lower. https://bit.ly/41ysS8c

There has been limited moisture changes at Bangerang/Sheep Hills, because of  the vetch with low biomass and water demands and 29mm rainfall for August.

Note, this paddock is sown to vetch, has been grazed and end use options include hay or brown manure if biomass is not generated in early spring.

There has been limited moisture changes at Minyip during August with 29mm rainfall for the month. The best moisture improvements (40%) observed this season was the end of July.

Winter moisture improvements have been down to 70cm after 60mm of rain from the last 2 months.

Deep moisture (80-100cm) was from 2022 and winter 2023 and has not been accessed.

There has been a small amount of moisture use at the 30cm depth during August.

Using the Soilwater app to simulate the moisture changes if you started the season with limited moisture reserves.

This could be the scenario after growing a cereal crop last season and limited harvest rain.

The model indicates 29% soil moisture which is an improvement of 2% for August.

Soil sampling on 14 August. Barley crop was patchy in development and is likely to be a factor to low crop water use in August.

There have been some recent shallow moisture improvements at the end of August after 25mm fell over a week.

Both the soil moisture probe data and modelled estimation show similar trends being wet on top and drier down deep.

There have been good moisture improvements at a depth of 70cm during August and that is a positive indicator to keep the barley growing in readily plant available water.

Barley is full flag emergence and the head forming in the plant.

Barley in wheat stubble at Raywood and showing good yield potential after the autumn break on 25 April.

It can now be established that there were 15% moisture improvements in July but no deep moisture changes in August.

Modelled soil moisture at Elmore with the Soilwater app compared to moisture probe data. Starting the growing season at 10%, the moisture is now at 61%.

Currently calibrating a new probe. Modelled soil moisture at Youanmite with the Soilwater app indicates a similar soil moisture percentage to probe data.

There are varied seasonal conditions and soil moisture levels in the Giffard area.

The moisture probe indicates good deep moisture that was generated from 50mm in early July.

A very dry period since (<25mm) has seen the canola quickly use the shallow moisture reserves and 35% was consumed in August.

The soilwater app model indicates if canola was established early, its current growth and soil moisture use would be exceeding rainfall received in August.

There have been small moisture improvements at 30 - 40cm at the end of August after the water use of canola at full cabbage/stem elongation created small water deficit when rainfall didn’t meet crop water requirements in mid-August.

Photo taken 14 August and soil core review.

There have been moisture improvements at the 80 - 100cm zone at the end of August and filled the soil profile close to full.

Photo of faba beans at Hamilton soil moisture monitoring site 14 August.

There have been moisture improvements (10%) to a depth of 60cm during the end of August rain. Yield prophet model shows some similar trends but slightly more deep moisture.

Photo from the Yalla-Y-Poora site on 15 August. Barley growing and canola in the background of the old monitoring site location. Soil core review link.