Knowing when frost strikes is key to avoiding total crop losses.
In-paddock temperature measurement could assist grain growers in determining whether their crops have been subjected to frost, therefore enabling them to quickly activate strategies to salvage a return from affected crops.
Temperature monitoring within a paddock in frost-prone areas is seen as an important tool, yet very few growers measure temperature at the susceptible parts of their property, according to Agrilink Agricultural Consultants principal consultant Mick Faulkner.
Mr Faulkner, who is part of the Grains Research and Development Corporation’s National Frost Initiative project ‘‘Spatial temperature measurement and mapping tools to assist growers, advisors and extension specialists manage frost risk at farm scale’’, says growers should consider using temperature loggers to more accurately identify when low temperatures occur.
‘‘Until now, frost identification has often been registered by the presence of ice at or after dawn, at ground level near the farm residence,’’ Mr Faulkner said. ‘‘But this may not reflect the actual temperatures at the susceptible parts of a paddock where crops are being grown.
‘‘Often frosts that have occurred earlier in the night but have cleared by dawn are missed, and frosts that caused ice on lawns are assumed to have had a similar effect in paddocks but that may not necessarily be the case.’’
Temperature monitoring equipment, such as Tiny Tags, iButtons and weather stations, are currently commercially available. These tools can help inform frost mitigation strategies and enable growers to accumulate data over numerous seasons to develop farm frost incidence and severity maps.
Such equipment is recommended as part of an integrated management plan to enable growers to build their knowledge base of their properties to mitigate the impacts of frost, a central focus of the GRDC’s NFI, of which the spatial temperature measurement and mapping tools project being led by Steven Crimp from CSIRO is a major contributor.
Mr Faulkner said temperature loggers should be situated at or just above the canopy height and raised every week or so during the growing season to account for crop development, particularly when the head is emerging (booting to milk development or Growth Stage 40-80).
‘‘As this is the most sensitive stage for the plant, accurately measuring temperature experienced by the head is most critical at this stage.’’
Mr Faulkner said the time from frost damage occurring to identification was critical.
‘‘Identification of frost damage is important because it enables a grower or adviser to understand the impact of frost on yield and extent of the area of damage. Assessment provides information on financial exposure and immediate mitigation options which include cutting for hay or silage, and grazing a standing crop.’’
Mr Faulkner said the parts of crops that should be inspected regularly included:
■Cereals — juvenile damage in high stubble loads; all internodes during stem elongation and the reproductive period; the soft tissue above each node; the stem where the flag leaf attaches; whole heads during and after booting; anthers, stigmas, embryos and grain.
■Pulses — juvenile damage in high stubble loads; leaf death of lentils, stems of faba beans and lupins; bacterial blight of some pea cultivars; flower abortion; developing pulse pods; and grain inside pods.
■Canola — leaf damage in juvenile plants; stem splitting; flower abortion; developing pods; and grain in pods.
■More information on frost management can be found in the GRDC Tips and Tactics publication, www.grdc.com.au/ManagingFrostRisk