Rains across WA grainbelt prove game-changer for winter crops

Neil Lyon, August 14, 2020

‘JUST IN TIME’ rainfall across most Western Australian grain growing regions has been a game changer for the 2020 season, increasing the chances of WA producing at least an average total winter crop of around 15 million tonnes.

WA growers have planted a record area of crop of close to 8.5 million hectares, and whilst most growers are saying it is not as good as 2018, the extra area planted is in the potentially better yielding regions west of the Albany Highway and areas of the South Coast that still, potentially, have time to improve.

There is also less fallow in the low rainfall areas, and much of this is in better shape than 2018.

In its latest crop report released today, the Grain Industry Association of WA (GIWA) estimates the state will produce nearly 9 million tonnes (Mt) of wheat, 3.7Mt of barley and 1.23Mt of canola this season.

GIWA Oilseeds Council chair and crop report author, Michael Lamond, said the recent rains had made a massive difference to WA crop prospects.

“The deep low pressure over the South Coast in the first week of August was just what the doctor ordered. It brought good rain from 30 to 200 millimetres right along the South Coast and the south Stirling,” he said.

“That not only means country that virtually had no rain will have some cover, but means it has really improved the prospects of the other crops that were quite patchy. That goes right across to the Esperance port zone.”

Mr Lamond said further rain again last weekend fell right across the grainbelt.

“It has come in the nick of time and, whilst it hasn’t provided a lot of profile for spring, it has kept things going beautifully,” he said.

“There was country in the eastern low rainfall areas where crops sweated off too much yield potential, but they will stabilise now. And there was a big corridor down the centre of about 1 million hectares that was well below average. They are up to about average now.

“It has made a massive difference in the prospects. It was on a knife-edge. It could have gone either way. But now we are looking at about 15 million tonnes in total.

“It is skewed towards wheat. It could be 60 per cent of total grain this year. It hasn’t been that high for a while.”

Mr Lamond said the 8.5 million hectares of winter crop were looking promising and the production estimate of 15Mt could end up being conservative.

“We have crops that have accelerated to the stage where it is like an early late break rather than a late late break,” he said.

“For the central regions the crop is in a sweet spot as far as the flowering window goes to minimise heat shock and minimise frost risk.

“As you go south the cool temperatures since the rain started have slowed things down a little which has been a good thing.

“The only area that missed out was the Lakes district which got rain but needs more. They were looking sensational but they ran out of steam. They are going to need more rain.”


Kwinana Zone

Kwinana North Midlands

The recent rainfall has recovered the potential grain yield in the dry corridor running north to south in the centre of the region. Prior to the rain on the weekend, the rainfall split the region in half with the better areas to the west having twice as much rainfall as directly adjacent to the east. Further east, the summer rains have kept crops ticking along until this last series of fronts. The crops in the areas that did receive the summer rain are now set up for at least average grain yields. The west coastal regions have been light on for rain all year and whilst the nitrogen use efficiencies have been exceptional from the lack of leaching rains, more is needed to reach average grain yield potential.

The most notable difference this year in the region has been the way various varieties have stood up to the dry / warm growing conditions. Longer season wheat varieties such as Scepter have crashed and will struggle to recover grain yield potential from now on, irrespective of what the spring brings. The quicker wheat varieties and particularly the noodle wheats have held up well and will be able to make use of the recent rain. The same can be said for barley in the region with Spartacus and Maximus also holding up well in the tough conditions.

Crops had completely exhausted the available sub-soil moisture prior to the recent rain events and whilst most crops “look way better than they should for the rainfall we have had”, more will be needed to hit overall average tonnages for the region.

Kwinana South

The two rainfall events of 10 to 25mm in the first week of August, followed by a further 10 to 15mm a week later, has turned the season around just in time. The dry central corridor picked up good falls of rain and for some, 20mm was the highest single rainfall total for the year to date. West and east areas of the zone had feared better all year and now the whole region is set up for at least an average grain production year. For individual growers who received higher totals of summer rain, grain yield potential is as good as 2018 which was a record production year for the region.

Crops have accelerated their development from the late May start and are at growth stages now similar to an early May start. For most crops, this very quick development has not come at the cost of lack of biomass, with most cereals having tillered well. Canola and lupins have been flowering for a few weeks which is earlier than the last couple of years. Lupin height is good this year, a relief for growers for a change as they will not need to get the “vacuum cleaner” out.

The projected flowering window for cereals looks to be in the “sweet spot” between heat stress and frost risk and if the rest of spring brings more rain, there could be a bit of grain around at harvest time.

Kwinana North East

There are crops with some terrific potential in the lower rainfall regions that received the summer storms in a line starting north of Koorda, across to Trayning, south east of Merredin and south across to Hyden. The very good crops in the southern strip missed out on the most recent rain with growers mostly receiving less than 10mm, although no one there is complaining.

Growers either side of this very good stretch of country have been a bit light on for rain during the winter and will need a pretty good spring to hit average grain yields. There are still some very poor areas on the north eastern and eastern fringes of the zone where grain yields will be well down, although the net result across the zone is likely to be an average grain production year.

There is a lot of wheat in the ground in the region and less fallow than in recent years. Some growers have “forced fallow” where crops were sown and have not germinated, although this is confined to the lower rainfall fringes.

Albany Zone

Albany West

The West Albany area has had dream run and is shaping up to be similar to last year for potential grain production.

Total winter rainfall has been below average, although this has resulted in less waterlogging and very few areas of the zone are showing crop stress from this at the moment. Crops have bulked up well and will be better able to handle any waterlogging that occurs from now on.

Canola has been flowering for almost a month and is still not in full flower, so the top end grain yield potential is very high. Cereal crops have tillered well and are very dense. Some were going off from the dry spell although they have greened up overnight following the rain last weekend. Barley has the flag leaf on the way out and wheat is mostly at the 2 to 3 node stage. Cereals were racing along up until the recent cooler temperatures and this made many nervous around the increased frost risk. Crops have slowed down a little now and the earlier emerged cereals will flower by the end of August which could cause still trouble.

Barley crops have had little Spot Type Net Blotch (STNB) to be concerned about although sclerotinia is starting to show up in canola crops with most requiring a spray.

The zone will still need some good rains in spring to finish crops off and dodge the frost to hit the yield levels of the last two years. With top end grain yield potential high, it is shaping up to be a very good year for growers in the region if the season goes their way.

Albany South

The dismal season for many has been completely turned around with falls of between 30 to 200mm from the intense low pressure system in early August. For many in the epicentre of the “no rain” area south-east of the Stirling Ranges, it was their best rain for a couple years and has halted the run of record low rainfall. It is incredible what one rain event can do, with some areas of the zone going from the driest July/August period to the wettest on record.

Many growers received surface run-off to put some water in dams that have been dry for three years. Pasture is still tight for most.

The patchy crops in the region will have time to benefit from the rain even though they had been pushed along from the warm dry conditions. Cereals were running up to head prior to the rain and lack canopy density. It is hoped the recent rain and cool temperatures will put the “brakes” on crop development and let cereals produce some late tillers to top up grain yield potential.

Canola tonnage for the region will be capped at below average due to “gappy” establishment, with the better crops possibly hitting 1.5T/ha for whole paddock averages.

Frost is a major concern for many growers as there is still a long way to go before frost risk drops off for the season.

Albany East (Lakes Region)

The region had been experiencing the best year in recent times with excellent crop growth from the good start and small regularly spaced rainfall. Crops were just starting to run out of moisture and showing the signs of stress prior to the rain last week. The region mostly missed out on the higher totals which were received further north, with most growers receiving less than 10mm. The potential is still there for a well above average year, although the next month will decide, as total rainfall for many growers is below average.

The region will need a couple of good falls of rain in August and September as the crops have a lot of top on them, and without the sub-soil reserves of moisture, will quickly fade if the weather comes in hot and dry. The general comment from the region is that “we are starting to get nervous now that we have exhausted sub-soil moisture” and are living “hand to mouth”.

Crop development is at least two to three weeks in front of where it would normally be for the timing of the start of the season, which takes the pressure off potential heat shock to some degree, although it also pushes crops into more frost risk during spring.

Canola and lupin crops are the best they have been for several years with more biomass and grain yield potential above average.

Esperance Zone

Grain yield potential for the Esperance Port zone is “all over the shop” and the various sub-zones in the region have widely different potential.

The western strip from Ravensthorpe north, currently has above average grain yield potential and areas closer to the coast are good from the lack of waterlogging. The central regions north of town have picked up some good falls of rain and are now on track for at least average grain yields for all crops. Areas around Salmon Gums, Grass Patch and Cascades missed out on the “dump” of rain that areas to the west received in early August. Most of the zone only received light rainfall from the most recent fronts that passed across the State last week.

In general, across the whole zone the turnaround from the patchy start has been amazing and whilst crops are not perfect, most except for the very dry areas will now have the potential to reach average grain yields. Fertiliser management has been very difficult due to the lower potential at the start and gradually creeping improvement in the season. Crops are well ahead of normal development and whilst most growers are not expecting the zone to hit the records of 2018, it could still well be a good year.

Crops have been relatively clean from disease, as they have for most of the state until now. Insects have been ticking along at low levels all year and with the weather warming up, aphids and budworm are increasing in numbers where spraying is warranted.

Source: GIWA



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