WITH shorter seasons and increasing dry springs seemingly more common, hitting the optimal flowering period is more important than ever to achieve maximum yields, according to PhD student Bonnie Flohr.
Hailing from Lameroo, Ms Flohr is based at the CSIRO in Canberra, working with highly-regarded senior scientists John Kirkegaard and James Hunt to better define the optimal flowering period and develop strategies for cropping programs to better maximise the OFP.
Ms Flohr gave some preliminary research findings at recent grower events in the Mallee. “With autumn rainfall declining and OFPs coinciding with that marked rainfall decline, there is less flexibility in time of sowing with fast-maturing wheats to achieve the OFP,” she said.
Ms Flohr described the OFP as the time when risk of damage from frost, heat and drought were all equal. “This is the time that maximum yield is achievable,” she said.
But from research so far, Ms Flohr believes there are inconsistencies with today’s OFP guidelines.
“We believe past studies have overlooked water supply and demand,” she said.
Ms Flohr said they were using computer software APSIM – a highly-advanced simulator of agricultural systems – to better define the OFP, because it combined weather records, including water availability, plant phenology and temperature.
“It is a new approach, but it enables us to use 50 years of climate data and cross reference it with time of sowing of a mid to fast maturity wheat,” she said.
“We entered sowing dates at weekly intervals from April 1 to July 15 at a number of sites and soil types in south eastern Australia. We also applied yield reductions for potential frost events.
“We also applied fertiliser and a small amount of irrigation at sowing to ensure the crop established – which was important to see the true interaction between time of establishment and the environment.”
Ms Flohr said results from the project showed drought was having an increasing role in defining the OFP.
“With increasing extreme spring weather events, the data showed the crop is better off to flower a bit earlier,” she said.
She used Lameroo as an example, where the OFP was once September 4 to 19.
“But in the past 17 years, we have suffered some hard springs,” she said. “Today, the OFP is more like between August 25 and September 8.”
Ms Flohr said when they compared their data to the National Variety Trial guide on sowing date recommendations for fast maturity spring wheats (most commonly grown), the results did not match.
“The sowing window the NVT recommends starts at the right time, but the end dates are too long if you are wanting to hit the OFP,” she said.
Ms Flohr advised growers to consider timing cultivars to their environment to achieve the OFPs, such as combining slow-developing varieties with short maturing varieties.
“Farmers would have to consider growing more than one variety of wheat,” she said.
- Details: Follow Ms Flohr on Twitter @BonnieFlohr
