2021 Season: Cyclone Seroja has potential to be a season-opening game changer
Widespread summer rain across the grain growing regions of Western Australia has resulted in most regions starting off the growing season with subsoil moisture reserves. All regions have received average or above average January to March rainfall based on records dating back 120 years.
The rain has brought the hope of a good season to growers and with grain prices trading in the higher decile ranges, if the forecast rain over the weekend eventuates, it could be one of the best early starts for the state since 2005.
Cyclone Seroja approaching northern WA has the potential to be a season game changer, potentially bringing rain at a time of year when the cold fronts that typically just lick the south of the state in autumn, bring little rain to the grainbelt. Once the current tropical activity drops away, the next few months are predicted to drop back to a “neutral” outlook for rain, which means there is no strong signal as to what will happen – “we are not sure”. The strong Southern Annular Mode (SAM) that resulted in rainfall being lower than predicted last winter has had a significant impact on wind and temperatures along the west coast over summer. The predicted reduction in the strength of the SAM over the coming winter will be critical in influencing weather patterns.
The summer rain that has delivered useful subsoil moisture, has also germinated weeds that have needed spraying. In the north of the state these weeds have mostly been annoying summer species that require removing to conserve moisture and mineralised nitrogen. There have also been useful germinations of wild radish providing the opportunity to get a kill before the season kicks off. Further to the south of the state, the steady rain and cool temperatures have brought up winter weeds such as ryegrass, barley grass, brome grass, wild radish and capeweed which is unusual for that time of the year. The opportunity to get a knockdown on these weeds is gold and will take the pressure off pre-emergent herbicides once crops are sown.
Recent history also tells us that the rainfall we have received will have resulted in significant Spot Type Net Blotch (STNB) inoculum release. With no host present due to the volunteer barley mostly removed by summer spraying operations, the risk of damaging early STNB in barley will be much lower than normal. This will mean there will be less of a requirement to burn barley-on-barley paddocks and give valuable early fungicides a break from repeated use.
The subsoil moisture and chance of an early break to the season has resulted in a predicted kick in canola plantings and this year will likely be back to historically large areas planted of well over 1.4 million hectares.
The increased canola area will mostly be at the expense of cereals, spread evenly over wheat and barley and to a lesser extent for legumes and oat for hay. Apart from a certain increase in canola plantings, enterprise mix will not change a lot from last year for most growers. In the north of the state where lupins were ditched for wheat due to the late break, there will be a swing back to lupins if useful rains are received over the next week or so.
The current low price of pulse crops such as beans and lentils are going to put a halt on the increased plantings that we have seen in recent years.
The uncertainty around export oat hay demand has resulted in dedicated hay growers dropping intended plantings by two thirds in some cases. The swap will be to canola or lupins in the higher rainfall western rim of the grainbelt and to wheat or barley in the eastern lower rainfall regions.
Ian Foster, Department of Primary Industries and Regional Development
DPIRD climate summary
The major climate influence for Australia over summer was the La Niña event that developed later in 2020. It has now declined to inactive status. Greatest impact on rainfall mostly occurs from late winter through to early summer, and then most strongly over eastern Australia. This latest event has been somewhat patchy for eastern Australia, but has brought significant rain to southern WA (see Figure 1). This has come from tropical lows in early February and early March, and has provided soil water storage opportunities over much of the grainbelt.
The Southern Annular Mode (SAM) had an impact on temperatures along the WA west coast over summer. The SAM was in its’ positive model over much of the summer, in which westerly winds are further south than normal. A consequence of this was enhanced easterly winds and higher temperatures for the west coast.
Most climate models have neutral rainfall outlooks for the next three months for most of WA. Major climate influences for southern WA. This appears to be the result of neutral climate conditions returning to the Pacific Ocean, as well as no clear guidance on the status of the Indian Ocean Dipole.
Shorter-term weather events are likely to have greater impact, such as the expected crossing of Tropical Cyclone Seroja into the region between Shark Bay and Perth around 12th April. While rain projections are variable among models, there is potential for significant rainfall across most of the grainbelt.
Bureau of Meteorology seasonal outlook summary, issued 8 April 2021:
- Rainfall for May to July is likely to be below average for large areas of northern and eastern mainland Australia.
In May, the drier than average pattern also covers southern areas, with a drier month likely for much of the tropical north, Central Australia, and parts of the southern mainland of Australia.
May to July maximum temperatures are likely to be warmer than average Australia wide.
Minimum temperatures for May to July are likely to be warmer than average for the north western half of Australia, and across much of far southern Australia.
The El Niño–Southern Oscillation is neutral, as are most other climate drivers.
Additional information is available from:
The season is shaping up to be similar to 2008, with summer rain giving opportunities to sow early and incorporate break crops such as lupins and canola. These crops will be up from last year’s production due to having increased subsoil moisture. If rain eventuates over the weekend, growers will get straight into sowing.
As the previous two years saw more wind events and topsoil losses, growers have since been hesitant to sow break crops dry. However, due to the increased rainfall this year, it will not be the case. Much soil amelioration has occurred in the area with lots of deep ripping. There has not been as much spading done in the last year or two because of the risk of blowing, but spading wet this year has allowed good compaction of topsoil and therefore blowing risks are lower.
There will be less area going into fallow due to improved subsoil moisture, and unlike some other regions, many winter weeds and winter grasses have not germinated. spraying for radish and summer weeds such as Caltrop and Melons has been ongoing. There may be a slight increase in IMI-tolerant crops such as Chief wheat, where growers can sow early without having to worry about brome grass germination. Most of the canola in the region is hybrid, and much is RR. Canola area will likely increase over 10 per cent from the year prior, and the lupin area will likely increase by over 10 per cent as well due to having better profitability with an early start.
Kwinana North Midlands
The region has had 100 –to150 mm of summer rain, and most growers have covered the ground at least twice for weeds. The summer rain has brought up ryegrass, wild radish and brome grass, so knockdown sprays have been well worth the extra cost.
The western parts of the region are large oat hay production areas and the uncertainty around price will see significant areas of planned oat hay being swapped out to wheat, barley and canola in equal proportions. Oat hay area is likely to be down by 50 to 70 per cent this year. Hay exporters have been on the front foot advising growers of potential problems with reduced demand and this has enabled growers to make planned changes to their seeding programs. This is a welcome change from the early days of oat hay production and has continued to develop goodwill in the once “cowboy” industry, demonstrating how much the industry has matured over recent years’.
Canola sowings will likely be up slightly, though the potential increase in area will be limited by seed supply issues. Hybrid canola dominates plantings in the region and as you mov further north. seed supply, particularly in seasons where there is an early seeding opportunity, is becoming more of an issue as the swap out of open pollinated (OPTT) canola has increased in recent years’.
Noodle wheat area is likely to decline, with varieties such as Scepter, which is generally higher yielding, and Chief being favoured over varieties like Zen due to more weed control options. The total area of noodle wheat increased dramatically with the release of varieties such as Ninja and Zen and is not at risk of lack of supply as it was several years ago. Although the more recent release of higher yielding varieties such as Devil will continue to take area from the dedicated noodle wheat varieties.
The region has had 70 to 160 mm of rain, with Northam and West York receiving the higher rainfalls and less in the east.
Some canola, Illabo wheat and other long season wheat varieties are in the ground. Growers have been sowing canola dry this week in anticipation of rain. Canola area in the region could spike 10 to 15 per cent if rain eventuates over the next few days.
Barley area is likely to be similar to 2020. Barley area dropped back by about 20 per cent in 2020 due to uncertainty around price at planting time. The central region of the state had the largest pull back in area in 2020. Further to the north, most crops had already been planted when the China barley tariffs were announced, and to the south, barley still beats wheat at lower prices due to its yield advantage.
Lupin area is expected to remain about the same as in 2020, whilst some oat hay crops will definitely be dragged and replaced with canola or barley.
Kwinana North East
The Kwinana North East zone has received good summer rain and some of the areas that missed out last year have good reserves of subsoil moisture to start the year. The north and eastern fringes of the zone had a poor 2020 season. The summer rain has hit many of the areas that missed out in 2020 and if growers in these regions receive 10mm plus over the next week, large areas of wheat will be planted. The frost risk increases with April sowing, although for growers in the region the risk is worth it as the increase in yield from an earlier planting can usually counteract the risk of an early cut out to the season in spring.
The success with canola and lupins in areas that received summer rain in 2020 will likely see a slight increase in plantings of break crops for the region, although most will aim for cash from wheat. The area of wheat versus fallow will favour wheat if there are reasonable falls of rain in the next week. Due to the high proportion of cropping in the region, the increase in planted area and potential tonnage of production for the state could be significant.
The region has seen reasonable rainfall of up to 180mm for the year in some spots. Most areas are now dry down to 10cm and canola is currently being sown dry in anticipation of the rain on the weekend.
Weed knockdown sprays have been effective as there has been good germination of winter and summer weeds with knockdown applications working well with most growers applying one to two sprays.
Illabo wheat and barley, plus some dry seeded canola have gone into the ground. Anticipated rainfall for the next week will see further seeding commence in the next few days.
Canola area will be up slightly from 2020, with barley and wheat about the same and the canola areas being swapped equally with the cereals. Lupin’s area will drop as most growers have reserves for stock feed in silos. The oats area is expected to drop off a little for growers for the same reason as lupins.
The adoption of soil wetters has transformed the region giving growers the confidence to sow shallow and still get crops up on light rainfall events. The result of this has been a big swing to early sowing and has played a significant role in some of the recent very high grain yields in the region.
Some farmers are ready to sow dry, although the more risk adverse will wait until later in April or early May to sow. There are few weeds and green growth with less of a green bridge than usual for the region.
Due to the current canola price, there will be a push for more area sown. There has been a big swing into hybrid canola in recent years. Hybrid canola area is at least 70 per cent of the area in the west and about 30 per cent in the dryer areas to the east.
There may be a drop in legumes due to prices and the swap to canola. Barley will be similar to 2020.
There is some soil amelioration, some deep ripping, spading and claying in areas. Over time, deep ripping has increased, although, there is a question as to the value as the response does not last as long in the region. Topsoil blowing is a concern for growers as well now that there is an expectation of rain.
Growers are dry sowing ahead of the forecast rain. The adoption of soil wetters has taken off, with large areas now being sown with wetters as growers become more confident of getting crops up on low rainfall events. This, combined with subsoil moisture provides better protection from false breaks.
Summer rainfall has been good, with 70 to 90mm in most areas, with some dry pockets having 40 to 50mm. Good water supply has aided spraying and farmers have been over the ground at least once for weed control so far. Most growers are ready to go if it rains on the weekend and the upcoming rain will be critical for how much canola is seeded, with an increase of 10 per cent from last year predicted in response to good prices and chance of early rain. Canola area has fallen away over the recent run of dry years’ and there is a chance to potentially slot a break crop back into the rotation. The predicted increase in canola area will come at the expense of lupins and wheat.
Some Illabo wheat and canola has already been seeded, though farmers will likely wait a few days prior to known rainfall before making any final decisions on planting decisions.
Barley area will likely push up again this year at the expense of wheat, as the difference in yield and current prices has barley profit ahead of wheat.
The green bridge has not been completely removed in the region as some growers still favour green pasture growth over hand feeding when green pick is available at this time of the year. The green bridge will be a risk for growers, particularly for early season emerging canola and lupin crops.
The region has been experiencing unusually warm temperatures for this time of year, and while rainfall has been good with around 60 to 100mm plus in some areas, there are still dry pockets. As these are generally in coastal areas, growers are not hugely concerned and the rainfall that has fallen has largely gone to farmers who need it, such as in northern Beaumont and Salmon Gums.
There has been a lot of Illabo wheat and Vetch going in the ground with rainfall, though most seeding commenced after Easter or will start soon if there is rain. Canola will increase this season and will soon all be in the ground over large areas of the region. Barley area is expected to increase slightly from 2020. Pulse crops will be reduced this year due to poor yields and prices last season, as will lupins.
So far, two to three sprays have seen good knockdown results on most farms, though limited water supply for spraying as well as livestock watering, has caused issues for farmers especially in the Cascade and Scaddan regions.
Hybrid canola production in the region has taken off in recent years from the predominantly OPTT plantings of five years ago. Seed acquisition has been somewhat limited in the region (and many others) in recent years due to supply issues, with seed companies often not easily filling sale orders for WA growers. This has not resulted in a restriction in plantings to date, although, it will if supply cannot keep up with demand in the future.