Early sowing still a good idea despite frosty 2014
Time of sowing trials in New South Wales in 2014 showed that despite widespread frost damage, early-sown crops in most cases were still able to match main season crop yields.
CSIRO research team leader James Hunt said the results confirm that early sowing has a place in modern farming systems.
“The 2014 season was unprecedented in terms of stem frost damage, with the Junee trial site experiencing 18 stem frost events and 75 frosts in total, and while the early-sown crops did not out-perform main-season wheats, the results were not too bad, and it was the first season in a very long time where early sowing was not by far the most profitable thing to do,” Dr Hunt said.
Trial sites at Rankins Springs run by AgGrow Agronomy and CWFS and at Junee run by CSIRO and FarmLink research monitored the performance of crops sown in mid-April or mid-May.
The Rankins Springs site had an 18-month fallow and highest yielding treatments were winter wheats including EGA Wedgetail and Osprey sown in mid-April, with 5.7t/ha achieved from both cultivars. The best performing spring wheat, Gregory, achieved 4.7t/ha when sown in mid-May.
At Junee, winter wheats sown on April 7 yielded lower than spring wheats sown on May 21, with Gregory achieving 3t/ha compared to 2.5t/ha from Wedgetail. However the highest overall performers were winter wheats Wylah (3.7 t/ha) and Whistler (3.6 t/ha) sown on April 24.
“The winter wheats sown in early April were affected heavily by stem frost and Barley Yellow Dwarf Virus. The April 24 sowings were still hit by BYDV but avoided stem frost, so were able to perform far better,” Dr Hunt said.
While 2014 was a particularly difficult year for early-sown crops, Dr Hunt says that is no reason to think it will not happen again.
“We have to learn from what we can from 2014 in order to manage these risks in future. Learnings that growers can take away are that if sowing before April 20, winter wheats are at lower risk of frost damage because they are slower to move from vegetative to reproductive growth and have higher frost tolerance than spring wheats when in the vegetative stage,” he said.
“A lot of the crops severely damaged by frost were spring cultivars sown much earlier than their optimal sowing date, so if growers can plan their sowing program so that spring wheats are kept within five to seven days of their optimal sowing date, frost risk will be reduced.
“Finally, it can be a good idea on early-sown wheats to follow up seed dressings with foliar insecticides if aphids are a concern, to reduce the risk of BYDV damage.”
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