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In this newsletter, we have provided a snapshot across the state of soil moisture. For new readers, you can check soil moisture and temperature for many Victorian pastures (and crops) at Agriculture Victoria’s soil moisture monitoring website.
Our last newsletter showed extremely dry sites in East Gippsland and some good soil moisture profiles to the west of the state, despite a dry September. October rains have turned some of this around, ensuring a good spring in the northeast and some central parts of the state. The western district missed out on significant rains and some areas are very dry and experiencing a short spring.
Comments from 4 soil probe owners about their current season and how this is informing decisions for the season ahead is provided below.
Compiled by Jane Court, Dale Boyd and Raquel Waller
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| Map showing soil moisture in the root zone, Australian Water Outlook map (source Bureau of Meteorology) plus soil core data at probe sites, 16 October 2023 |
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The 'cores' on the map represent soil moisture at 0-80cm depth on 16 October 2023. Many of the moisture probes shown, have good to adequate soil water for plant growth (note that not all probe data is shown here).
The shading on the map indicates the west of the state has below average soil moisture. Generally, these soil moisture maps are matched with soil probe data, so it is of note the far west sites - Dartmoor and Harrow look to have good soil moisture at the probe paddocks despite little spring rain (see comments from Harrow site below).
However, a cropping site at Hamilton (not shown here but available at the website) is very dry to depth. Central parts the state, the northeast and much of Gippsland now have replenished soil moisture. Parts of East Gippsland and Towong shires have below average soil moisture for October.
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| Map showing soil moisture in the root zone at the end of September 2023, Australian Water Outlook map (source Bureau of Meteorology) |
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This map shows soil moisture in the root zone (0-100cm) was below to very much below average across the state with patches of lowest 1% of soil moisture, before the October rainfall.
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| Map showing rainfall-to-date in October 2023 (source Bureau of Meteorology, Australian Water Outlook) |
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The rainfall across Victoria in October was above average to very much above average in the central, east and north of the state. This therefore reflects the changes in soil moisture as seen between the first 2 maps.
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The Moyston site is part of the Perennial Pasture Systems (PPS) group which has soil moisture probes across members’ paddocks in central and west Victoria. For the past 3 years, spring pasture has been predicted for 3 of their soil moisture probe sites. The soil profile was full in each of these springs and with good seasonal outlooks, the predictions were generally for above average and extended seasons. This year, not all areas have received enough rain to replenish soil moisture. Moyston is one site that is now very dry. The topsoil is currently below 20% and less than 50% to depth.
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The graph below shows the pasture prediction from their September report that used modelling to predict what the rest of spring could be like given the dryness of the profile then.
Pasture growth rates were modelled (by Agriculture Victoria) given 10; 30; 50 and 70 decile weather (based on historic weather data) for the rest of spring with the long term estimated pasture growth for the area as the dotted line.
The pasture predictions indicated the pasture would have ceased growing without good rains (above 30 decile). The aim of these early predictions is to assist farmers make some early decisions about managing spring.
For more information about the PPS group go to perennialpasturesystems.com.au/
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PPS were successful in the Federal Government 'Smart Farms Small Grants Round 3' funding program, allowing it to commence a pasture growth estimate project which will report throughout spring. This year PPS were successful in gaining funding from a Wimmera CMA and Landcare Victoria grant to continue the project to produce pasture growth predictions.
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The rainfall chart at Balmoral shows a very wet June which kept soils sodden over winter, and with well below average rainfall recorded subsequently.
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Tim Leeming, Harrow
The soil moisture at Harrow is looking good to depth despite very little spring rain.This was due to carry over moisture from autumn and a very wet June. This made it a challenging season for lambing, being so wet, depite a very good autumn. Because the ground was sodden over winter, pasture growth rates have only just kicked off in the past 3 to 4 weeks and this growth is now running moisture down quickly. Without rain in the next week, it will be a below average and short spring. Pastures are short with a lot of clover, so quality is excellent and will be quickly consumed.
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The graph above shows the fast draw down of moisture in the top 30cm in the last few weeks. The pasture at this site has a high component of balansa clover.
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As the rainfall map above shows, some parts of central, northeast Victoria and Gippsland received good October rains (e.g. above 30mm). This has replenished soil profiles and ensured some, or a good spring.
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Martin O'Sullivan, Baynton
The feed wedge was running out prior to the rain, and we were concerned with the prospect of a short spring. Now we have higher confidence in the season and a longer spring. Feed quality is going to be better for stock from here on, because it has been managed and grazed with little excess, so new regrowth should be better.
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Damien Gerrans; Lima East Soil Moisture Probe (Gecko Clan Landcare Network)
Rains in early October came at just the right time. We had grazed down and dry sowed a pollinator mix of seed (sunflower, vetch perennial pasture etc) into the probe paddock just before rains. The paddock has residual ground cover which protected the soil from the rain and permitted water infiltration. Soil moisture had increased down to depth as a result.
Being autumn calvers, we usually wean in January. If we didn’t get rains, pastures would have started browning off and it would have also meant we would be looking at early weaning and selling stock early.
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Seeds are now shooting and pasture is kicking in and lifting up on the flats. It’s a win/win. The rains mean we can match feed to carrying capacity for the next few months which is critical to our business. We have peak demand for feed in late spring and summer with cows and calves in the paddocks. We don’t like to rely on fodder, so this rain means that feed will keep up to demand.
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Ken and Kym Skews, Ensay, East Gippsland
Up until 3 weeks ago the outlook was grim with very low rainfall through winter and early spring. The north facing slopes had dried off and feed was in short supply.
However, in the past 3 weeks we have had 120mm rainfall that has turned the season around. While there is not the feed available as there would be in an average spring, the grass is growing, and the pressure has come off a bit.
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We are still feeding younger cattle, especially the maiden heifers, which will hopefully assist cows to be in the required order for joining.
We are now optimistic that we will cut hay and silage this year. Prior to the rain this did not look likely. There is a need for follow up rain during the rest of spring.
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James Paulet, Livestock Industry Development Officer, Maffra
The recent rains have given the soil a good moisture base and will allow for the planting of summer crops or over sowing into older pasture stands with summer crops. At the Gippsland Research Farm, near Bairnsdale, the rain has filled the soil profiles nicely.
While soil moisture has increased, it is worth considering that evapotranspiration can consume this rainfall in 3-6 weeks depending on rainfall and rooting depth.
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The soil moisture monitoring website shows data from Agriculture Victoria soil moisture probe sites as well as a number from other organisations including the Gecko Clan and Perennial Pasture Systems group and Gippsland Agricultural Group.
Both soil moisture and temperature are measured at each site with sensors to depth (recorded hourly and uploaded from the field with the telemetry unit).
The website also provides additional site information on the soil characteristics and plant species.
The new dashboard allows easier and quicker access with an improved search function.
This allows farmers to distinguish between crop types being monitored, pasture and soil types and location rainfall, all of which influence soil moisture data.
There is also a Victorian seasonal outlook for 1 – 3 months and extended into spring/summer.
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