Can earlier sowing of slow maturing varieties increase whole-farm wheat yields in Western Australia?
CSIRO field experiments funded by the Grains Research and Development Corporation (GRDC) are taking place this year in a bid to answer this question, following promising preliminary research results.
CSIRO researcher James Hunt said crop simulation modelling suggested yield gains exceeding 0.5 tonnes per hectare were possible if slow maturing wheat varieties were sown early (from early April) in WA’s higher rainfall zones.
“The modelling work follows field trials in southern areas of Victoria and New South Wales which have demonstrated a significant yield benefit from applying this strategy,” he said.
“The eastern states trials showed that early sown wheat crops yield more because less water is lost to evaporation; roots grow deeper and use more water; water is converted to dry-matter more efficiently; and a longer stem elongation phase increases grain numbers.
“Adopting slower maturing varieties which allow for early sowing can also increase the frequency of planting opportunities and allow more crop to be sown and flower on time.
“We want to find out if yield increases can be achieved in the field in other environments including WA, where there are fewer early sowing opportunities and slow maturing varieties have not been specifically bred or evaluated.”
The WA trials will take place at Cunderdin, Kellerberrin, Wickepin and Kojonup, with assistance from Living Farm and Agrisearch.
Dr Hunt believes growers in some of the State’s medium and higher rainfall areas might be able to achieve significant yield gains from early sowing of slower maturing varieties.
“The modelling work, using the Agricultural Production Systems Simulator (APSIM), found that potential yield gains were highest in regions such as Esperance and Kojonup where there are more frequent early rainfall sowing opportunities and the yield potential is higher,” he said.
“However, the early sowing strategy actually decreased average farm yields in modelling for some locations including Mingenew.”
Dr Hunt said all growers should adhere to some general principles if they wanted to sow crops early.
“Early sown crops should be seeded into weed and disease-free paddocks,” he said.
“Growers also need to know their area’s optimal flowering period and how to achieve it with different sowing dates and a range of varieties.
“If planning to graze crops, higher seeding rates and up-front nitrogen application will maximise early dry-matter production.”
More information about early sowing can be found in the GRDC Time of Sowing Fact Sheet at www.grdc.com.au/GRDC-FS-TimeofSowingWest.
Information is also contained in GRDC GroundCover TV videos featuring interviews with Dr Hunt, available at www.grdc.com.au/GCTV13-EarlySownWheat.
Caption: CSIRO researcher James Hunt says growers wishing to sow early in 2014 need to be ready to take advantage of early sowing opportunities if they arise. Photo by Mark Peoples CSIRO.
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