WithTheGrain: Sowing date gives farmers power over barley outcomes

Author: | Date: 04 Apr 2018

Kenton Porker presenting at the recent GRDC Updates in Adelaide.

Five years of barley research in the southern region is coming to a close having equipped farmers with detailed knowledge of how to manage a range of barley cultivars on offer.

South Australian Research and Development Institute* (SARDI) research scientist Kenton Porker says the Southern Barley Agronomy project, a GRDC investment managed by New South Wales Department of Primary Industries, has shown sowing date is the biggest agronomic lever that growers have in getting the most out of a variety.

Mr Porker says optimising yield is best achieved by matching variety phenology to sowing time and environment to ensure flowering occurs at the right time to minimise exposure to frost, head and moisture stress.

The research has also expanded understanding of the varietal differences that achieve yield such as plant type and tillering ability which enables further fine tuning of yield and quality using other management strategies such as plant growth regulators, nitrogen, grazing and seeding rate.

“Out of all of the work we’ve done looking at nitrogen, seeding rate and other management tools, as long as you get the target yield environment right for a given variety, then sowing date is still king,” Mr Porker says.

“If growers get that right they are 80 percent of the way to achieving maximise yield and grain quality performance.”

The 2017 trials run in South Australia had sowing dates of 28 April and 18 May at Kingsford and 20 April and 8 May at Loxton and results were consistent with long term trends. Frost, heat and moisture stress at flowering time had some effect on trial results, with frost damage occurring in Loxton (figure 1) and some significant heat events were experienced at Kingsford (figure 2).

While faster developing varieties such as Compass, Rosalind, Hindmarsh, Spartacus CL and LaTrobe are well adapted to the low to mid rainfall zones of SA, Mr Porker says it was clear in 2017 there should be caution with these varieties in frost-prone areas and pre-May sowing.

Scattergram depicting the flowering date and grain yield relationship of commercial barley varieties sown at Loxton on 20 April and 8 May 2017
Figure 1: Relationship between flowering date and grain yield of commercial varieties sown 20 April and 8 May at Loxton in 2017.
Scattergram depicting the flowering date and grain yield relationship of commercial barley varieties sown at Kingsford on 28 April and 18 May 2017
Figure 2: Relationship between flowering date and grain yield of commercial varieties sown 28 April and 18 May at Kingsford in 2017.

Mr Porker says the European variety RGT Planet is suited to mid to higher rainfall environments where Commander is currently grown, presenting higher yielding results in trials. In terms of Clearfield® varieties, he says Spartacus CL outperformed Scope CL and offers a grain size improvement

“The one thing to think about is RGT Planet is still not a malting variety just yet, at the moment it’s only for feed, so for now growers would be targeting yield rather than quality,” he says.

“It has passed the first stage of malt accreditation and we should know this time next year if it is classed for malting grades.”

Mr Porker identifies RGT Planet as a medium variety in comparison to Australia’s fast developing varieties, with a sowing date of early May. He says it is still not suited to sowing in early April. In 2017 trials, RGT Planet yielded higher than Westminster and Commander despite the three varieties having similar flowering windows at both the Kingsford and Loxton sites (figure 3).

He advises RGT Planet be sown in high-rainfall areas with a yield potential beyond four tonnes per hectare.

Scatter plot graph showing the yield performance of RGT Planet, Rosalind, Compass and Spartacus CL across 2017 trials in South Australia
Figure 3: A Finlay and Wilkinson plot of yield for RGT Planet, Rosalind, Compass and Spartacus CL across 2017 NVT trials in SA (n=13). The fitted lines for linear regressions are shown.

“Being a slightly later maturing variety, RGT Planet is less suited to later sowing and the lower rainfall environments with target yields of under 4t/ha,” he says.

“The test weight of RGT Planet is low compared the other varieties so it may be more prone to quality downgrading and if there is heat or drought at flowering time or during grain fill it does tend to show a high tendency for small grain.”

Trial results also showed Spartacus CL and RGT Planet to consistently produce higher grain numbers than Compass, however this does coincide with reduced grain weight in these two varieties of up to 15 percent and 10 percent respectively. RGT Planet achieves this via the number of grains per spike and consistently achieves high numbers per spike while Spartacus produces more spikes per square metre and less grains per spike.

These tendencies can affect variety choice decision-making according to Mr Porker, as these traits will occur regardless of sowing date in a variety such as RGT Planet, whereas as Compass will have lower grain number from early sowing.

In the low-rainfall zone (LRZ) or later break scenarios, Mr Porker says farmers should look to Compass or Spartacus CL, which have recently received malting status.

“In a low-rainfall environment, with yield potential of between 1-4t/ha, Compass is the best suited,” he says.

Compass has grain size stability so it is more likely to get malt quality even if the season turns badly and there is drought or heat,” he says.

“In higher-yielding areas, Compass shouldn’t be sown too early as it will lodge and the research from the Southern Barley Agronomy program has shown there is no yield advantage from sowing it early. “

*SARDI is a division of Primary Industries and Regions SA

GRDC research code: DAN00173

More information

Kenton Porker kenton.porker@sa.gov.au, 0403 617 501

Useful resources

2018 SA Sowing Guide

2018 Victorian Winter Crop Summary

GRDC GrowNotes™ - Barley (southern region)