As the southern cropping season draws to its close, farmers will be closely monitoring the state of their winter crops, particularly in relation to frost events in late August, which have induced widespread crop damage in conjunction with drought stress.
Speaking during the 2018 Henty Farm Machinery Field Days in the GRDC marquee, NSW Department of Primary Industries crop physiologist, Felicity Harris, based at the Wagga Wagga Agricultural Institute, said producers should monitor the extent of crop damage from these frost events which could impact on potential yields.
She encouraged growers to observe crop development at the timing of frost, as damage is generally seen seven to ten days after the event.
“Depending on the growth stage of the plant, it can be a bit hard to identify the damage so one of the first things we are suggesting is look at crop development and perhaps mark a couple of areas in the crop for future assessment,” Dr Harris said.
“The first sign of damage is that crop development does not progress, for example, plants in later stem elongation stages at the time of the frost events, may not push a head out. So by marking some plants and reviewing them in seven to 10 days will help identify stem frost damage”
“Look at your high risk paddocks, areas of the farm prone to frost first and look for damage in those areas, if identified then look further afield. It can be useful to rank paddocks in terms of production potential when making decisions”
Dr Harris emphasised how the timing of crop development will also have some bearing on its susceptibility to frost damage.
“More advanced barley crops that have been developed a little bit more ahead of the frost have escaped damage in some instances,” she said.
“We can see they are progressing quite well and filling grain, so they have a lot more potential.”
More advanced barley crops that have been developed a little bit more ahead of the frost have escaped damage in some instances
- Dr Felicity Harris
It is worth noting not all crops will be affected, nor indeed not all sections of a paddock, and it will be of benefit to consider options.
Timing of sowing might actually help crops
Across the plant and across the paddock is how NSW Department of Primary Industries crop physiologist, Felicity Harris, based at the Wagga Wagga Agricultural Institute, assesses the potential damage done to cereal crops by an untimely frost event.
“Anything that was in a vegetative stage is fairly safe, but crops that were in the early stem elongation phase all the way through to the reproductive stage, which is the bulk of our cereal crops, have all been susceptible given the extreme frost events” Dr Harris said.
She said the severity of the temperature on crops which are already seriously moisture-stressed, compounds the effect of a frost event as obviously plants which are already under some form of stress will be more sensitive to damage.
“The frost in August has taken a bit time to show because we have had cooler temperatures after the frost; whereas frost in early September should show up quite quickly because of the warm temperatures which followed,” Dr Harris said.
“There is no substitution for getting out and having a thorough look across paddocks, observing plants and estimating the damage will enable growers to make an informed decision moving forward when considering options for grain yield potential, fodder or grazing”.
She made the point when considering the relativity late planting of some crops due to the dry window of sowing opportunity, many crops might actually escape a lot of damage.
“Because we have had a varied establishment due to late sowing this year, there is quite a bit of variability within paddocks in terms of growth stage,” Dr Harris said.
She advised growers to look at the development of the crop as it is really important to monitor potential areas of damage.
