Options for frost affected crops
Your decision making around this challenging situation
Once a frost event (especially at or after flowering) has occurred, the first step is to inspect the affected crop and collect a (random) sample of heads to estimate the yield loss incurred. In the event of severe frost, monitoring needs to occur for up to two weeks after the event to detect all the damage. After the level of frost damage is estimated the next step is to consider options for the frost damaged crop.
This podcast on crop salvage options (from the landing page) could be a useful guide to assist your decision making.
Option 1: Take through to harvest
If the frost is prior to or around (growth stage) GS31 to GS32, most cereals can produce new tillers to compensate for damaged plants provided spring rainfall is adequate. Tillers already formed but lower in the canopy may become important and new tillers can grow after frost damage, depending on the location and severity of the damage. These compensatory tillers will have delayed maturity, but where soil moisture reserves are high, or it is early in the season, they may be able to contribute to grain yield. A later frost is more concerning, especially for crops such as wheat and barley, as there is less time for compensatory growth. The required grain yield to recover the costs of harvesting should be determined using gross margins.
Option 2: Cut and bale
This is an option when late frosts occur during flowering and through grain fill. Assess crops for hay quality within a few days of a frost event and be prepared to cut a larger area than originally intended pre-season. Producing hay can also be a good management strategy to reduce stubble, weed seed bank and disease loads for the coming season. This may allow more rotational options in the following season to recover financially from frost, for example to go back with cereal on cereal in paddocks cut early for hay. Hay can be an expensive exercise. Growers should have a clear path to market or a use for the hay on farm before committing.
The hay and silage fact sheet looks at how to make the most of a failed winter crop.
Option 3: Grazing, manuring and crop topping
Grazing is an option after a late frost, when there is little or no chance of plants recovering, or when hay is not an option. Spray topping for weed seed control may also be incorporated, especially if the paddock will be sown to crop the next year. Ploughing in the green crop is to return organic matter and nutrients to the soil, manage crop residues, weeds and improve soil fertility and structure. The economics need to be considered carefully.
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