Tips for better canola establishment in low and medium rainfall areas

Author: Melissa Williams | Date: 13 Mar 2014

Image of flowering canola in Western Australia's low rainfall region

Economically optimal plant density levels for different herbicide tolerance canola systems might be less than previously thought in WA’s low and medium rainfall areas.

This has been a finding from 2013 trials conducted as part of a new five-year GRDC-Department of Agriculture and Food WA (DAFWA) ‘Tactical break crop agronomy in Western Australia’ project.

It aims to fine tune tactics for profitable production of non-cereal break crops, especially in areas where these are not traditionally grown.

Project leader Mark Seymour, of DAFWA, said last year’s canola plant density trials showed that canola establishment can fluctuate very widely – from 30 to 80 per cent – with changes in soil moisture, soil temperature and variety.

Key results from these trials were outlined at the Agribusiness Crop Updates and will be also be presented at various Regional Crop Updates across the State. For information and registrations go to: www.giwa.org.au/2014-crop-updates

2013 canola plant density trial background

Twelve sites were set up in low and medium rainfall zones, from Mullewa to Salmon Gums, to assess plant density responses in the varieties:

  • Open pollinated (OP)  triazine tolerant (TT) CB Telfer (low rainfall zone) and ATR Stingray (medium rainfall zone)
  • Hybrid TT Hyola 450TT
  • OP RoundupReady (RR) GT Viper
  • Hybrid RR Hyola 404RR

Eight plant density levels were used, from five to 80 plants per square metre.

Establishment results

Average establishment rates across all varieties at all sites ranged from 30% at Miling to 43% at Cunderdin and 68-81% at Wongan Hills.

In general, Hyola 404RR had the highest average establishment rates across all trial sites at 54% and GT Viper had the lowest average establishment at 39%.

Across all varieties at all sites, low target plant densities of five and 10 plants/m2 achieved the best average establishment rate of 55%.

Mark said a density of 20-30 plants/m2 was adequate for most varieties at most trial sites to achieve good establishment, ensure robust weed competition and produce yields of about 0.8-2 tonnes/ha.

In general, he said using high target plant densities above 40 plants/m2 lowered average paddock establishment rates to 45% - and in some cases significantly reduced crop yields and returns.

Table 1: A summary of field establishment rates (%) of canola in a range of conditions 

Conditions

OP varieties  

Hybrid varieties

Normal – just enough moisture to get into it

50

65

Excellent (Wet, warm, targeting 40 plants/m²)

65

80

Dry sown, tough start

35

50

Dry sown but ok start

45

60

Optimal target plant density

Hybrids

On average, across all sites, the RR hybrid Hyola 404RR had the lowest average economically optimal plant density level of 20 plants/m2.

At a cost of about $31/kg for seed and relatively high yields at low plant densities, the yield and economic response from this variety plateaued at 20 plants/m2.

The average optimal yield response for the TT Hybrid, Hyola 450TT, across all sites peaked at 23 plants/m2 before flattening out.

OPs

The OP TT varieties CB Telfer – the most popular in WA’s lower rainfall areas – and ATR Stingray had higher optimum plant density levels than hybrids or RR canola at an average of 31 plants/m2. This was driven by lower seed costs to increase plant density.

The RR OP variety GT Viper had a lower optimum plant density on average than OP TT canola varieties at 24 plants/m2, but this tended to be marginally higher in medium rainfall areas.

Seeding rates

From the plant density responses observed across the trial sites, the project team has compiled an indicative guide to seeding rates to achieve optimal targets:

Hybrids

Hyola 404RR – 2.1kg/ha for 20 plants/m2
Hyola 450TT – 1.4kg/ha for 23 plants/m2 (this low seeding rate can be risky and requires calibration of machinery for low seeding rates).

OPs

CB Telfer– 2.4kg/ha (or higher with retained seed) for 31 plants/m2
ART Stingray – 2.1kg/ha (or higher with retained seed) to reach 31 plants/m2
GT Viper – 2.2kg/ha for 24 plants/m2

*NOTE: This guide is based on a single year of trial data from 2013. Seed size, germination and field establishment rates will also affect seeding rates.

The bottom line

The RR hybrid Hyola 404RR produced the highest, or equal highest, gross margins at 10 out of 11 trial sites in 2013.

The OP RR, GT Viper, consistently produced less profit per hectare than the hybrid RR Hyola 404RR.

The hybrid TT Hyola 450TT had higher gross margins than the OP TT canola at six trial sites, including two trials in the low rainfall zone - Salmon Gums and Holt Rock. Mark said the trials showed optimal plant density for canola in low and medium rainfall zones tended to vary with variety and herbicide tolerance production system.

This could require adjusting plant densities according to rainfall zone.

GRDC Project Code: DAW00277

More information:

Mark Seymour, DAFWA, 08 9083 1111, mark.seymour@agric.wa.gov.au

Useful resources:

2014 Agribusiness Crop Updates Papers: http://www.giwa.org.au/2014-crop-updates
GRDC Fact Sheet – Growing Hybrid Canola: www.grdc.com.au/Resources/Bookshop/2010/10/Canola-Growing-Hybrid-Canola-Fact-Sheet

Disclaimer

Any recommendations, suggestions or opinions contained in this publication do not necessarily represent the policy or views of the Grains Research and Development Corporation.

No person should act on the basis of the contents of this publication without first obtaining specific, independent, professional advice.

The Corporation and contributors to this publication may identify products by proprietary or trade names to help readers identify particular types of products.

We do not endorse or recommend the products of any manufacturer referred to. Other products may perform as well as or better than those specifically referred to.

The GRDC will not be liable for any loss, damage, cost or expense incurred or arising by reason of any person using or relying on the information in this publication.

CAUTION: RESEARCH ON UNREGISTERED PESTICIDE USE

Any research with unregistered pesticides or of unregistered products reported in this document does not constitute a recommendation for that particular use by the authors or the

authors’ organisations.

All pesticide applications must accord with the currently registered label for that particular pesticide, crop, pest and region.

GRDC Project Code DAW00277

Region West, North, South