Ag Weather Forum

September was a harsh month for wheat growers in the southern Australia states of South Australia and Victoria. Rainfall was meager -- more than 6 inches less than last year. August and September totals in these two states are as much as 8 inches below a year ago. For the season so far, at least one grain industry official in southeastern Australia calls the lack of precipitation the driest so far this century.

And then came the frost events. During a two-week period in mid- to late-September, temperatures fell to minus 6.5 degrees Celsius (20.3 degrees Fahrenheit). A frost assessment article by Liz Wells of Lachstock Consulting describes the area covered by these hard freezing temperatures as extending from "southern New South Wales to southwest Victoria, and to South Australia's western Eyre Peninsula, making it the geographically biggest frost event to hit southeastern Australia since 2011."

The harsh cold was the result of a strong push of cold air from Antarctica that focused on the southern portion of Australia. Its impact was no doubt enhanced by the dry soils due to a lack of moisture to release heat and mitigate the cold damage. Environmental scientist Benjamin Brooks, writing on Forestry.com, noted: "Moist soil retains more heat than dry soil, releasing it overnight and keeping air temperatures around the plants slightly higher, thus reducing frost duration and intensity."

Lower crop production from the area hit by this combination of drought and frost is a given, as ruined wheat, barley and canola are now useful only for forage. USDA's Weekly Weather and Crop Bulletin noted that the extended dryness already affected the wheat crop prospects, even before the additional impact of frost events. "The persistent dryness in parts of the (Australia) southeast has slowly but steadily reduced crop conditions," stated the bulletin for the week ended Sept. 29.

Industry-related estimates for production show some large drops from the five-year average in South Australia and Victoria. In South Australia, the latest estimate from the state's Department of Primary Industries and Regions SA (PIRSA) calls for South Australia's wheat crop to total 3.2 million metric tons (mmt), which would be 36% below the state's five-year average. Crop losses of similar magnitude are also expected in Victoria and southern New South Wales.

The entire Australia wheat crop is likely to be less than recent estimates because of the drought and frost impact in the southeast regions. However, favorable weather elsewhere is expected to counter the weather damage in the southeast. The total Australia wheat crop, projected by subscription service Australia Crop Forecasters, is pegged at 30 mmt, down from 32 mmt in the September USDA World Agricultural Supply and Demand Estimates (WASDE) report. A new WASDE report is scheduled for Oct. 11.

Bryce Anderson can be reached at bryce.anderson@dtn.com

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