Research has shown early wheat sowing opportunities vary greatly between locations, prompting the WA Department of Primary Industries and Regional Development to remind producers to research their seeding decisions thoroughly.
The department has urged growers to consider historical rainfall data in association with current stored moisture levels and variety selection when contemplating whether to sow before the traditional break of the season.
Department scientists analysed climate data from 1975 to 2017 alongside wheat variety responses to sowing times at Mullewa, Merredin, Katanning and Esperance.
Research officer Meredith Guthrie said while historical data gave an indication of likely rainfall, it provided no guarantee.
“The results showed there was a 30 per cent chance of seeding opportunities in April at Mullewa and Merredin, while at Katanning and Esperance there was a 50 per cent chance,” Dr Guthrie said.
“The data from past years provides a useful means of assessing the chances of early season rainfall events, in contrast to three month climate forecasts produced in March and April which have a low predictive skill level.”
Dr Guthrie advised growers to consult the department’s weather station summaries on its website to assess past years information about April rainfall.
Despite widespread rainfall early in 2018, current stored soil moisture now varies greatly across the Grainbelt, with levels particularly low in the north and eastern areas.
“Heavy rainfall that fell from ex-tropical cyclones Joyce, in January 2018, and Kelvin, in February 2018, is no longer present in the top soil, so growers would be wise to check current stored moisture levels for their property when making early sowing decisions,” Dr Guthrie said.
Variety selection is another major consideration when sowing early to manage the risk of frost and heat stress.
Department research officer Brenda Shackley said if growers chose to sow early, they would be wise to sow a long season variety.
Ms Shackley said growers should match the maturity of a variety with the sowing date to maximise their wheat crop’s yield potential.
“Department early sowing trials, with co-investment from the Grains Research and Development Corporation, planted in April have shown mid-long maturing varieties typically yield best – except at frost-affected sites, where very long, winter maturing wheats produce the highest yields,” she said.
“In frost prone areas, delaying sowing into May is one of the best ways to maximise yields, to avoid the risk of flowering during a frost event.
“In areas that are not at risk of frost, department trials show sowing in April offers no yield advantage compared with sowing in early May.”
The department’s Flower Power tool can help growers to choose a variety’s sowing time to minimise the risk to frost exposure and maximise yield potential.
The online tool can be used to predict wheat flowering times of up to three different varieties at various sowing times and the risk of frost or heat stress in a selected location.
More information on this research is available on the department’s website by searching for ‘stored moisture’ and ‘early sowing’.
Source: WA DPIRD