A trial looking for solutions to water repellent sandy soils has given growers new reasons to consider ameliorating soil options to alter the properties of the crop canopy and reduce frost severity.
One observation from the claying, spading and mouldboard ploughing trials for the sandy soils in Western Australia was that frost appeared to have less impact on crops grown in spaded or inverted ameliorated sandy soils, with or without addition of subsoil clay.
However, growers should interpret these observations with caution, as important questions regarding potential effects of soil amelioration on frost damage are yet to be answered.
While claying has long been considered an option that may reduce frost damage in sandy surfaced soils, these findings that related to spading and soil inversion are an interesting discovery for researchers and support past work in the National Frost Initiative.
Lawson Grains 'Walyoo' property manager Mark Drake, who is hosting the GRDC-invested trials on behalf of the Department of Primary Industries and Regional Development (DPIRD), says 2016 was an unusual year in terms of number and severity of frost events in the West Midlands region.
For his business, Mark says, the trials are demonstrating the importance of improving soil structure to combat a range of constraints, most importantly soil water repellence.
DPIRD soils research scientist Dr Giacomo Betti, who is managing the trials, says while the effect of frost on crop yield and floret sterility is not yet clear, the finding of less floret damage in the 2016 trial barley could be significant in the long-term search for solutions to combat its damaging effects in many areas of WA.
Dr Betti says the results from the spading treatments weren't just a one-off.
He says data from the 2017 and 2018 trials show similar trends to those seen in 2016.
After the 2016 results, Dr Betti set up canopy air temperature loggers to see if the benefits could be measured in subsequent lupin and wheat crops.
For each season, the data confirmed that canopy air temperatures were consistently higher in the spaded treatments during frost events compared to the untreated control treatments.
"When it comes to canopy air temperatures, it doesn't appear that the effects from the spading are crop specific," he says.
Canopy air temperature benefits have also been measured at several other sites across the southern and central wheatbelt, across several seasons.
Results have been gathered across multiple sites over a three-year period.
DPIRD frost research team leader Dr Ben Biddulph says researchers don't yet fully understand the reasons behind these findings and more data from well-instrumented trials are required.
"This is currently being worked on with frost and soil research teams," Dr Biddulph says.
More information: Dr Giacomo Betti, 08 9956 8554, Giacomo.Betti@dpird.wa.gov.au