The Grain Industry Association of WA's latest crop report, released on Friday, says the state's crop was in good shape until recently and the potential tonnage was climbing "to a point where we were looking at a very good year".
"However, the complete lack of finishing rains has now put a question mark over final tonnage," the report said.
There are still areas in the southern regions that can recover grain yield potential if they receive 20mm of rain in the next two weeks.
"Without this, the total tonnage for the state could be closer to 15 million tonnes rather than 17 million tonnes as it stands now," the report predicted.
The current total estimate of 16.85 million tonnes consists of 9.3 million tonnes of wheat, 4.27 million tonnes of barley, 2.22 million tonnes of canola, 555,000 tonnes of oats, 440,000 tonnes of lupins and 73,000 tonnes of pulses.
Grain producers in WA are hoping for spring rains within the next fortnight. (Dean Lewins/AAP PHOTOS)
Grain yields had started to slide in many regions, with the large area of wheat the most affected.
WA is the nation's top wheat exporter and there are about 500,000 hectares more wheat planted than in 2023.
The crop report said it was difficult to finish off wheat with little or no spring rain "and it is the normally more reliable rainfall regions that are suffering the most".
The lack of finishing rains in September, combined with warm sunny days, has had crops digging deep for residual sub-soil moisture.
But moisture reserves are low due to below-average growing season rain for most regions.
"Without further rain in the next two weeks, the slide in tonnage will continue," the report said.
In better news, the large area of barley (1.8 million hectares) planted this season is in good shape.
"Barley, in general, has had a dream run this year with low levels of disease and the lack of waterlogging in the lower lying areas where barley is often targeted," the report said.
There has also been no frost and this has helped to keep barley tonnage estimates higher.
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