Unreliable rainfall during April to May in the Wimmera and Mallee may lead to poor or late crop establishment in spring wheat crops, which may void their optimal sowing window.
Research being conducted as part of the Grains Research Development Corporation (GRDC) ‘Development of crop management packages for early sown, slow developing wheats in the southern region’ project, is aiming to identify well adapted wheat varieties for that early, opportunistic break.
Three wheat varieties in 2017 and again in 2018 have had three irrigation rates, 10, 25 and 50mm applied to simulate an autumn break. These varieties have been sown at four different times of sowing (TOS). A further nine varieties are receiving 10mm of irrigation over the four TOS.
Trials at Curyo and Longerenong by mid-July 2017 had received 145mm and 135mm growing season rainfall respectfully on top of these irrigation rates. This is a stark contrast to the 2018 season where trials at Narraport and Rupanyup (where the trials have been established in 2018) have only received 76mm and 82mm growing season rainfall, respectively (to 18 July).
TOS had an impact on performance in 2017 with low establishment from the very early time of sowing, which was believed to be a result of high soil temperatures. High temperatures can result in the shortening of the coleoptile of the wheat seedling.
Results from 2017 were reasonably contrasting between the two sites (Longerenong and Curyo). Winter wheat lines achieved yields that were not significantly different to the spring wheat lines of Trojan and Scepter when sown at the optimal timing at Longerenong. Compared to Curyo, where Trojan and Scepter flowering mid-September produced the highest yields.
Given the significantly drier start in 2018, seedlings have found the conditions difficult. Varieties sown on the 20 March (time of sowing one) at the Narraport site received either a 10, 25 or 50mm irrigation, but then only received 4mm of rainfall for the next 44 days.
The stress placed on the plants at this early stage will influence final yield. The question will be how well the varieties recover to produce grain?
La Trobe University researcher Dr. James Hunt will be present at this year’s BCG Main Field Day to be held on Wednesday 12 September at Narraport, 18km north-west of Birchip.
Dr Hunt has done extensive research on spring wheat performance in the Wimmera and Mallee region and will explain the influence different seasonal conditions have had on early wheat performance.
Additionally, Dr Hunt will provide results from 2017 which showed that early sowing may present opportunities to increase overall farm profitability by spreading the sowing window without excessive risk of frost and heat.
The BCG Main Field Day is on September 12 at the BCG main research site at Narraport, on the Nullawil-Birchip Rd. For more information about the event visit www.bcg.org.au/events or phone 03 5492 2787.
This article was published in the Stock and Land, 26 July 2018.
