How Farmers are using Weather Certificates to Manage Frost Risk

Jonathan Barratt

July 23, 2021

The late Autumn break for many growers means that in some areas we have an increased chance of frost occurring. Extreme temperatures are estimated to cost the broadacre industry $1.1billion annually, this figure could potentially increase given late sowing in many areas and, favourable growing conditions so far in the season. However, late sowing increases the potential for Frost, resulting in significantly reduced yields, if not, a complete wipeout. Here is how some farmers are mitigating their Frost risk with Weather Certificates.

Frost events, whether direct or indirect, cause significant yield loss for wheat producers. A stem frost is clearly visible; however, head frosts are not, and often is the case that the crop looks great in the paddock yet only reveals the damage at harvest through lost yield. In Australia, the annual yield loss due to frost is about 10%, which results in $120 and $700 million economic losses each year. More importantly, when we consider the estimated yield loss due to late sowing to avoid frosts, the estimated losses are more than double nationally. Frost is indiscriminate if you are in a Frost zone and growers should take some steps to insure against losses.

Managing frost is a “balancing act”, farmers if they sow early risk flowering in the frost window, whilst later risk yield loss due to heat stress. In the eastern grain regions yield loss attributable to direct frost and delayed sowing strategies was estimated as being as high as 38% for mid flowering cultivars. Farmers looking to sow in the optimal window tend to shy away from this window simply due to the 10 days of risks associated with frost after anthesis.

In some regions in the Wheatbelt sowing has been delayed by the late Autumn break which means that the crop’s flowering risk is significantly heightened. As can be seen by Stapper and Fischer’s phenological chart below.

Flowering Risk from Delayed Season start (Source: M Stapper & R Fisher, 1990)

Although, Frost damage is generally patchy and is influenced by many factors the losses can be managed via the use of an appropriately timed Weather Certificate. If you have sown late and planted a species that is susceptible to frost then you would be at risk of suffering frost damage and important yield loss.  In the following example, we look at a grower near Lake Bolac, Vic who finished sowing on the 10th of May.

Using the Agricultural Production Systems sIMulator (APSIM), we calculated that if the sowing was completed on 10th May, and then flowering would occur approximately 7th October, so maximum damage that frost would occur would be 10 days after. Given actual climatic data for the 40-year sample, the farmer could expect to yield 3.1t/ha. However, a modeled frost event and according to APSIM, this yield was drastically reduced to 1.3t/ha. Of the 40 years that where simulated significant drops in yield occurred in 1982, 2006, and 2013.

Conditions dictated that the crop would be more vulnerable to stem or head Frost. As such the grower near Lake Bolac would be wise to look at a Weather Certificate that covers yield loss caused by Frost. The modeled loss of 1.8t/ha at a price of $300 ton on 1000ha is as much as $540,000 which if a Frost event occurred would turn this season into a scratched year.

Why risk this when a simple Frost Protect Weather Certificate could assist in helping to offset this loss.

Leave a Reply

Your email address will not be published.