Earlier this week (August 30 and 31) the mercury fell with temperatures dropping below zero for prolonged periods (2.5 to 5 hours) at Swan Hill (min -1.1°C), Hopetoun (min -0.7°C), Jil Jil (min -2.8°C) and Horsham (min -2.0°C).
Research has suggested that frost has become one of the most significant risks to broadacre grain production in Australia with recent estimates putting the economic cost (for wheat and barley) up to $63million (Fellowes 2006).
BCG research officer Kelly Angel said there are several factors that have made modern cropping systems more prone to frost including earlier sowing dates and the uptake of mid-season varieties more likely to flower during the most frost prone months.
Drier spring conditions, which have been a more common occurrence over the past decade, also have an associated increased frequency of frost, with an average of five more days of frost in September 2000-2010, compared to the previous 10 years in the Western region (Steve Crippers.comm).
Monitoring crops after a frost – particularly from late booting until maturity when they are most susceptible – will ensure any damage is identified early and management decisions can be made accordingly.
While a late frost can have a severe impact on the yield and quality of the crop, past experience has shown that a crop that experiences a frost at flowering can still be cut for hay and some income can be recouped.
Earlier frosts, such as those that occur prior to GS30, may slow crop growth but generally the plant can recover.
BCG is involved in a GRDC initiative examining how frost impacts grain production and management strategies that can reduce crop losses.
This year BCG is running large scale (1ha) research trials at Rupanyup and Hopetoun to investigate how stubble load (slashed/mulched and burnt/removed) and architecture (standing and horizontal), as well as crop architecture (eg. skip row seeding), influence frost intensity and duration. The trials were sown with standard farm scale equipment, taking advantage of yield mapping technology.
Last season BCG produced a special technical bulletin to help growers identify frost damage. Members can download this resource here.
Other useful resources include: ‘Risk-based approach for best frost management’, Pulse and canola frost identification: the back pocket guide, and Cereal frost identification: the back pocket guide.
For more information about BCG’s frost management research, phone Kelly Angel on (03) 5492 2782.
