Winter 2014: Volume 5 Issue 3
Edition: Volume 5 Issue 3 September 2014
Editor: Zita Ritchie, Dairy Extension Officer-Climate Risk, Warrnambool
Rainfall over June in Victoria's dairy regions was average to above average with some parts recording the highest rainfall on record for the month. Conditions for July were a mixed bag, with areas north of the great divide drier than normal. In August, conditions were very dry in the north and normal to slightly dry in the south. Winter rainfall was generally lower than average in the north and normal in the south of the state. After the warmer autumn temperatures, winter maximums averaged normal in Victoria's dairying areas and minimums were slightly warmer in East Gippsland, far West Gippsland and far east South West.
The outlook for spring rainfall is average from most models but a few show slightly drier conditions. The development of a late El Niño is still possible, but statistically events over summer have variable effects on Victoria's rainfall. Signals of an earlier forming El Niño weakened as ocean temperatures cooled during July. Although ocean temperatures recently warmed in August, an Indian Ocean Dipole (IOD) negative event has occurred over winter. This is often associated with wetter conditions for Victoria (particularly the South West) but this event has now decayed and appeared to be a very weak event.
Dairy State Round up – Autumn (June - August) 2014
Mirboo North: 8
|Region||Spring Rainfall Deciles (Sept-November)|
|Northern - Irrigation|
For the Northern Irrigation region, the above average rainfall in autumn continued into winter for June and the first half of July. From mid-July, the weather then turned very dry. Temperatures were average to cold, with a number of severe frosts occurring through July and August. Dairy farmers who took advantage of the good pasture and crop growing conditions in autumn and early winter, were able to rely less on supplements. As soon as the gravity fed irrigation districts season commenced on August 15, many farmers were irrigating, due to drier conditions. Despite low rainfall over July and August, the Goulburn irrigation districts received 100% determination of high reliability water shares (HRWS) on August 1, for the first time in 15 years. However, the allocation price by winter's end reached over $100ML. If conditions remain dry in spring, further upward pressure on allocation prices, concentrates and fodder would be expected.
Very high rainfall across the district in June signalled some tough conditions for farmers. Cold, foggy conditions throughout June and July ensured the ground stayed very wet. Pasture production was poor and the good bank of feed from autumn was whittled away. Lameness and mastitis were rife. August was dry and sunny which improved the situation considerably but by the end of the month most farmers were becoming anxious for further rain to ensure a good spring.
|Coastal East Gippsland|
Winter in the Orbost region was very mild throughout, with only a few short frosts, resulting in quite good winter grass growth rates. Most farms had an adequate feed wedge all season, except for those located on river flats that experienced minor flooding. Cow condition over winter was pretty good on most farms with production ticking along nicely. A timely rainfall event in the last week of winter means Orbost farmers are generally in a good position for soil moisture at the start of spring.
A warmer than average winter was experienced throughout the Bairnsdale region, resulting generally in very good cow condition and less health issues, reflected in better milk production. The combination of mild winter conditions, largely due to very little or no rain for most of July and the first half of August followed by very timely late winter rains to replenish soil moisture, resulted in earlier and vigorous spring pasture growth in the first week of September.
|South West Victoria|
Winter growth rates were average across the South West region. With a good start in June most farms had reasonable cover and were able to maintain appropriate grazing rotations. Good rainfall in July did result in waterlogging in some parts of the region requiring some tactful management to maintain milk production and pasture cover. Over August some waterlogging issues continued that impacted on growth rates and pasture cover but the warmer weather towards the end of winter and into early spring showed a pleasing increase in pasture growth rates and cover.
|Macalister Irrigation District (MID)|
Generally the MID had a wet start to winter, which gradually became quite dry until the end of August. Late winter rainfall events resulted in wide variation in soil moisture content between the free draining soils and the higher clay content, lesser draining ones; in the latter case a few paddocks hadn't dried out adequately at the start of spring. Some farmers made an early start to the current irrigation season using available spill entitlements. The overall pasture growth result for MID dairy farmers over winter was pretty good on average. The irrigation season (2014-15) began with an 85 per cent allocation in mid-August from Lake Glenmaggie. This allocation increased to an early 100 per cent guarantee on High Reliability Water Shares due to new and permanent Thomson Dam rules regarding drought reserves policy. Maintaining pasture quality in the MID will need to be a key focus earlier this spring season particularly as a result of the more favourable winter growing conditions.
East Sale: 5
|South & West Gippsland|
For the most part, winter in both southern and western Gippsland regions was essentially an average one; a bit wet at times but generally not too bad. The fair bit of cloud, some sun and a couple of frosts all contributed to slow mid-August pasture growth, while late August pasture growth was favoured by a run of sunny days. As we begin spring, soil moisture is generally good, as are feed supplies. The milk to feed price ratio is favourable for feeding purchased supplements where needed.
Seasonal climate outlook
This seasonal climate outlook has been put together with assistance from Dale Grey, editor of our seasonal climate risk e-newsletter, The Fast Break.
Model Summary for 28 August 2014
For spring, average rainfall/slightly drier and slightly warmer/average temperatures are the most common outcomes predicted by the models.
Current outlook (August 28)
Previous outlook (July 28)
1-3 month outlook
4-6 month outlook
1-3 month outlook
4-6 month outlook
Slightly warm/ warm (El Niño)
Warm (El Niño)/ slightly warm
Slightly warm/ warm (El Niño)
Warm (El Niño)/ slightly warm
Modelled Climate and Ocean Predictions for Sep-Nov and Dec-Feb
A closer look at what models are predicting for Victoria in the next 6 months, focusing on Indian and Pacific Oceans, rainfall and temperature.
The Southern Oscillation Index has remained negative for all of August but mostly less than -8, within the neutral range. Recently the SOI has made a foray into more negative territory, currently at -12.1 (1 September). This is indicative of pressure patterns along the Equator behaving more El Niño like, but much of this signal is coming from the higher pressure around Darwin rather than Tahiti going lower.
Sea surface temperatures (SST) cooled slightly more along the Equatorial Pacific Ocean during August[MR1] . The eastern Pacific remained below the El Niño threshold of +0.8oC, (1 September NINO3 +0.46oC), central temperatures also cooled (1 September NINO3.4 +0.32oC). Moisture sources remain good to the NE and NW of Australia.
The Southern Annular Mode is currently neutral and has been weakly positive and negative over August. Models predict the SAM to remain neutral or go weakly negative over the coming two weeks. The SAM has most effect on winter rain in Victoria.
The Sub Tropical Ridge of high pressure was positioned slightly lower than its normal position for August, blocking the passage of frontal systems to Victoria. The STR has its most predictable influence over winter rainfall.
Still a possibility of an El Niño?
By Zita Ritchie, Dairy Extension Officer, Warrnambool (adapted using information from the Bureau of Meteorology)
Spring is already upon us and you may be wondering about the current state of play. Looking at the majority of models, the outlook for spring rainfall is average with a couple saying slightly drier.
In autumn, sea surface temperatures had warmed up and trade winds were pointing strongly towards an early developing El Niño. However during July, sea surface temperatures in the Pacific Ocean cooled off toward neutral temperatures, weakening the chance of earlier forming El Niño. Since then, signals have been weak. However in August some warming again occurred in the central and eastern Pacific due to the weakening of the trade winds. If the trade winds remain weak, more warming towards El Niño thresholds is possible. This means the chance of an El Niño developing in 2014 is at least 50%, which is double the normal likelihood of an event. Although an El Niño could still develop in late spring it is unlikely to be a strong event.
On the other side of Australia, changes have also taken place in the Indian Ocean. The Indian Ocean Dipole (IOD) index has been below negative 0.4 °C (the negative IOD threshold) since mid-June, which means 2014 has been classified a weak negative IOD year. A negative IOD is often associated with wetter conditions in winter or spring for Victoria and could be countering the effects of the current El Niño-like ocean pattern in the Pacific. The IOD negative only seems to have lasted for the minimum two months and has recently disappeared. This event seemed not to do much for rainfall in June.
Aside from the Pacific and Indian Ocean, moisture sources in the Timor and Coral seas have been slightly warmer than average which is more favourable for moisture. However, pressure patterns for August have been higher over Victoria which has pushed a few possible rainmaking events south, causing drier conditions in northern Victoria, particularly around the Wimmera and Mallee regions. We need to see a return to normally placed high pressure systems soon for favourable moisture conditions to take hold. The large highs have also stirred up the Arafura Sea and made it cooler, which when coupled with the higher pressure at Darwin, may not mean we get too much moisture from directly north.
Managing the Season Ahead - Spring 2014
Greg O'Brien, Dairy Extension Officer
With the chance of El Niño having dissipated and no strong indicators to suggest rainfall might exceed the average this spring, it might be best to make plans based on average rainfall. The exception for a drier than average spring in central Victoria means planning for the conditions might be wise. It is good risk management to keep an eye on weather conditions as spring unfolds and adjust plans as needed.
Spring temperatures are likely to be warmer than average which affects growth and water use by plants. This would mean late spring growth might be a bit slower and late sown crops might be under greater heat stress during establishment. On the plus side, warmer temperatures in early spring would boost growth coming out of winter. Silage surpluses will appear earlier if this occurs.
With the current pleasing soil moisture profile on most farms, a good start to spring growth is almost guaranteed. However, things can change quickly over spring for rain fed farms, particularly where there isn't a good depth of soil moisture. Plans to make the most of a strong early spring pasture surplus should be put in place, as the early to mid-spring growing conditions are more reliable.
It may be worth considering boosting early spring growth with nitrogen fertiliser to increase pasture surpluses. Generally, nitrogen boosted conserved feed can be made cheaper than the landed price of purchased fodder. This said, the costs and risks involved should be weighed up and compared against purchasing in any feed shortfall.
All farmers are encouraged to look for early signs that pastures can be "banked" for silage. When it gets to the stage that the cows start to leave grass behind (i.e. they aren't grazing down four to six centimetres between the clumps) this means that it is time to reduce the daily pasture/supplement allocation and take some paddocks out of the rotation for conservation.
Silage quality has a big impact on cow performance when it is fed back. High quality diets are required for high intakes to achieve good milk production. Harvesting the silage crop around the time it would otherwise have been grazed will result in a high energy and protein fodder, so for best milk production that should be the targeted harvest window.
In addition to having higher quality silage, pasture regrowth and total spring production are both associated with short lock up periods. After winter, every tiller becomes a seed head and needs to be replaced by a new tiller. Pastures regrowing after a short lock up will have higher tiller density due to less shading. Although silage yield per hectare will be lower, more hectares can be cut. Nonetheless, lockups normally have more benefits than disadvantages. Although the ideal short lock up time of four weeks from last grazing generally means multiple harvest dates and substantial rewards.
Early season silage will be better quality than later season silage due to the effect of seed head development on quality later in the spring. So there are feed quality advantages from generating an early surplus where practical. This could be worth around two and a half litres per cow per day when the silage is fed back.
Those with soils that are not currently saturated should be planning to begin their fodder cropping as soon as possible to take advantage of ideal growing conditions in mid-spring. It may be wise to delay the sowing date of fodder crops on paddocks that are at risk of waterlogging. Select forage varieties that will be ready for grazing when a pasture shortfall is anticipated. Planting a range of crops with different maturity dates can allow feed to come on tap continuously over the summer to help fill a feed gap.
For southern districts, cool season forage crops are ideal for early spring sowing (e.g. brassicas, some clovers, chicory and plantain). These all have high quality content which will be great for maintaining high milk production well into summer. The hotter Victorian dairy regions are likely to have temperatures that are too high for many of these species to grow well during summer.With forage crops sown later in spring or early summer there is a greater risk of failure due to high temperatures and drying of soil surface during the establishment phase. Sowing technique and seed bed preparation can reduce some of this risk, but can't eliminate it. Summer grasses such as millet and sorghum hybrids are well suited to summer growing conditions. They can handle some moisture stress but good soil moisture or irrigation is required to obtain profitable yields.
The summer grasses have lower feed quality than cool season species, so will not support as high a milk production. For this reason they should only make up a proportion of the cows diet. They are useful where growing conditions are too hot and/or dry for cool season species to perform well. They also have few pest and disease problems.
Dairy farmers will need to keep an eye on spring seasonal conditions in the grain and hay growing districts. Grain prices are looking favourable for dairy farmers at this point. Crops got off to a great start in autumn but winter was generally drier than desired. As usual, spring rains will have a big say on grain yields.
Hay crops are generally looking good and there are some frosted cereal crops that are going into silage or hay. This might mean fodder could be fairly well priced at harvest. Some dairy farmers are considering filling their sheds through purchasing hay or buying standing hay crops. It all depends on the price, so buy on quality. Hay isn't cheap if it isn't of the nutritional quality needed.
There is a little concern amongst dairy farmers in the Northern Irrigation Region regarding temporary water prices this irrigation season. It comes down to the cost-benefit. Do you purchase water and grow your own feed or purchase feed? During spring, the growth is so high that it is hard to imagine a case for under-watering as the more profitable option. This said, every situation is different, so do your own sums.
The Winter back page
View the latest BOM Climate Outlooks video (which focuses on how to understand climate outlooks) and to get a bird's eye view on what else you might like to learn and discover about them.
You can also access both the rainfall and temperature updates and view the Climate outlook overview.