This newsletter introduces the new soil moisture monitoring website that makes it easier to access all the soil probe site data. 

While winter and spring rains have filled a number of soil profiles across the state, there are still some notable exceptions in Gippsland. 

This report was produced with data up to 7 October and does not include the effects of recent rain across the state. We have also included the spring pasture predictions for the Harrow and Baynton sites, produced as part of the local groups' Enhanced Producer Demonstration Sites (funded by Agriculture Victoria and MLA), investigating the use of soil moisture data for spring management decisions.

Dale Boyd and Jane Court

In this Issue

• The new soil moisture website
• Was winter colder or warmer than usual?
• Central (Baynton)
• North East (Greta)
• Gippsland (Bairnsdale)
• West Gippsland (Giffard West)
• South West (Dartmoor)
• West Wimmera (Lawloit)
• South West (Pigeon Ponds/Harrow)

The new Agriculture Victoria soil moisture monitoring website shows data from the 36 Agriculture Victoria soil moisture probe sites (17 crop and 19 pasture) across various locations and agricultural industries. Soil moisture and temperature to depth are measured automatically at each site (recorded hourly and uploaded from the field based on available mobile connection). The site also provides some information on the soil type/texture and pasture or crop species. The new set-up will mean easier and quicker access and the improved search function will allow farmers to distinguish between crop types being monitored, pasture and soil types and locations all of which influence soil moisture data. 

To access the new website.

The last newsletter reported a good early start to autumn for much of the state which included some good follow up winter rains in some areas, such as the southwest, central and north east of the state. The winter was generally drier than average (see map below) except in far east Gippsland.  A dry winter is often good for stock management and some sites have had good pasture production even if this has led to depletion of soil moisture. The site results below show the variability in how wet soil profiles are and have been.

Early autumn rainfalls leads to good leaf area that is also likely to improve winter pasture growth rates. But was this also supported by a warmer - or longer and colder - winter? The two graphs below show a picture of the minimum and maximum temperature anomalies across the state (source BOM). These indicate cooler minimum temperatures in the west of the state and slightly warmer temperatures to the east but overall slightly warmer maximum temperatures across most regions.

Soils at the Central Victorian sites filled early and have generally stayed wet to depth. A relatively dry September meant moisture in the top 10-40 cm was used quite rapidly for plant growth, but follow up rains topped soil moisture up to capacity on both the basalt and granite soils. An early start to the season provided leaf area for better pasture growth over winter, providing good feed quantity and quality for lambing ewes.

The soil temperature graph above indicates that the soil cooled down to below six degrees (top 10 cm) about a fortnight earlier this year, compared to last year, due to a sequence of frosts in June. In both springs, temperature reached about 10 degrees towards the end of September, with a positive pasture response.

The local Grasslands Society of Southern Australia (GSSA) branch ran some paddock trials on both the basalt and granite paddocks and measured some good responses to gibberellic acid over winter.

As part of the local group's Enhanced Producer Demonstration Site (hosted by the Central Ranges GSSA branch and funded by Agriculture Victoria and MLA), predictions for spring pasture growth have been modelled by Melbourne University using the soil moisture as of 1 September and are shown in the two graphs below. The predictions using a wetter than average spring (as forecast) are for above average growth rates and a slightly longer growing season and the updated predictions from October support these further. There is about a 65 per cent chance of above long-term median pasture growth rates in November to early December.  

The North-East site at Greta has three paddocks with soil moisture probes - a phalaris paddock and two annual pastures.

According to the site host, the paddocks produced good emergence of pasture in the autumn, with an ideal plant density over the farm (not just the flats, as the rises can be poor in the dry years). It is a great season to date. The current estimation of FOO on soil moisture paddocks is estimated at about two t/ha. Fertiliser was applied to the paddocks with 200 kg/ha of super molybdenum in autumn and nitrogen fertiliser at the start and end of winter with 70 kg of urea at each application (avoiding the coldest months). Paddocks are being rotationally grazed now to assist pasture quality for high lamb growth rates after a period of set stocking when ewes were lambing.

The main limitation to pasture growth at the moment is considered by the owner to be nutrition, if paddocks have not been adequately fertilized this season. It has been a great break and a long season and these types of years grow a lot of dry matter but the nutrient removal is above the normal, so the nutrients need to be applied to maximise the season. If pastures are not correctly grazed this spring, pasture digestibility could crash pretty quickly. He will continue to rotational graze paddocks to maximise weight gain with lambs, with the first to start being processed in November. No hay or silage planned as stock will utilise the feed grown.

The graph below shows the soil moisture to depth on the phalaris paddock and illustrates how the soil was gradually filled during the autumn and reached a full point in winter. Moisture is being used currently at 30 to 40 cm depth.

Similarly, the graph below shows the soil moisture to depth for the hill pasture at Greta, also with a full profile over winter, but a small usage of soil water occurring in the 40 to 50 cm zone in the absence of rain in early late August/early September.  Conditions are 25 per cent wetter than this time last year.

The site host reported that compared to the previous year, there was good emergence of pasture after the January 21 summer rain event (70 mm) and this was like an autumn break as rain continued in the following months and the growth rates have been extraordinary. Despite being dry in June, July was really wet and ground rigs could not apply fertiliser so it was spread by air in August.  Fertiliser was applied as 40 kg/ha of potash and 80 kg/ha of urea on 7 August and the same is planned after late September grazing.

There is a lot of feed across the farm and in the autumn there was a significant sowing program of annual pastures and crops. They are all being well used currently for both grazing and hay and silage opportunities. Crash grazing winter cereals aims to use the spring growth with the excess to be returned as residual back into the soil for some longer term benefits.

The owner considers that the main limitation to pasture growth at the moment is nutrition, if paddocks have not been adequately fertilized this season as trafficability was limited in August. The region needs further rain to extend the season as the dry September is drying the profile as the probes clearly show.  "The current growth is not the same it was early September.  We need to keep on top of the export of nutrients with silage and hay and be conscious of potassium levels if dry-matter is removed."

Paddocks will continue to be rotationally grazed and tightened to around 21 days. Hoping further rain can be received and extend the season with improved pasture species that have the capacity to grow to summer. No hay or silage is planned in the site paddock as stock will graze and the aim is to improve the soil and reduce exports of nutrients.

The owner has been monitoring the soil temperature measured by the probe as there seems to be a visual correlation of growth to soil temperature, and more so at 20 and 30 cm than at 10 cm.

The Central Gippsland site at Giffard West is a perennial pasture paddock. Soil water content this summer has improved in response to rainfall, but it has also been depleted as the pasture grows in response to available water.  Current conditions are better than this time last year although there is still little moisture ''in the bank" and the deep profile is still dry.

This site has a mix of lucerne and phalaris with some ryegrass and the soil moisture graph shows the filling of the soil in autumn and use down to about 40 cm over winter. The site owner reports that the paddocks have only just got 'wet' in the last few weeks and have supported good pasture growth and animal production. The paddock is well set up for another good spring. The owner was lucky to take on some cattle agistment early (before being assured of a good spring) and this has proved an excellent decision. Cattle have been held on longer than usual to use the feed as grass hay will not be cut this year due to a full hay supply from last season.  The lucerne/phalaris paddocks on the farm, like the probe site paddock, are shut up for silage and half will also be cut as second cut lucerne.

The sites at Harrow (Pigeon Ponds) had great breaking rains that increased the soil moisture levels during autumn and good autumn pasture growth. The profile was rated as full during early July and has been at that status since. Images of pasture growth in late August showed evidence of water logging. Spring rains have met pasture water demands. Full profiles in October provide great moisture reserves to be drawn upon and extend the season.  Conditions are currently 30 per cent wetter than this time last year, indicating yet another excellent spring in this area.