Wider rows offer yield potential

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Photo of Ben Cripps

Ben Cripps (pictured) farms with wife Angela and parents Terry and Ros at Ogilvie and Binnu, WA. GRDC-funded trials on their property in 2014 found that using low seeding rates of 1.5 kilograms per hectare at 60-centimetre spacing produced marginally higher yields – about 80kg/ha – than using seeding rates of 3kg/ha at 30cm spacings. As a result, the Cripps family planted this year’s 730ha hybrid Roundup Ready® and open-pollinated triazine-tolerant canola on 60cm spacings.

PHOTO: Martin Harries

Growers in northern WA are bucking the trend and trialling wider rows to chase canola yield and reduce input costs

Many agronomy studies recommend sowing canola and lupins in narrow row spacing to maximise yield, yet growers in the northern region of Western Australia are going against this to reduce costs. Trials in this region proved lupins can be grown using row spacings of more than 50 centimetres with good results, so growers put canola to the test in 2014 to measure yield response. The results showed that wide rows are a viable option for growers who want to reduce seeding (and potentially fertiliser) costs without losing yield.

As part of the GRDC-funded Tactical Break Crop Agronomy project, the Department of Agriculture and Food, WA (DAFWA) and the Northern Agri Group planted three grower-sown trials and three small plot trials.

Grower tip

Keep seeding rates in wide rows above
1 to 1.5kg/ha to avoid poor crop emergence.

These trials were paired within the same three paddocks and given common treatments. Five of the trials were replicated. It was found that:

  • yield was greater in wide rows at one trial, statistically the same in three trials and lower in one;
  • lifting the seeding rate suppressed yields in the narrow and wide rows, but more so in narrow rows;
  • at three of the five replicated sites, wide row spacing combined with a low seed rate was the highest yielding row spacing/seed rate combination (Figure 1 reflects one of the trial sites, where grower Ben Cripps planted four varieties at different widths and seeding rates – low seeding rates and wide row spacing produced the highest yields);
  • by the early to mid-vegetative growth stage (72 days after sowing), the crop sown in wide rows produced a similar amount of biomass to the narrow rows and plants had filled in the gap between the rows;
  • at maximum biomass, biomass was not significantly different between wide and narrow spacings, apart from one site where more biomass was produced in wide rows compared with narrow; and
  • wider rows conserve moisture until later in the growing season and can help to drought-proof crops and reduce overall risks.

The message to growers from all the trials is that shifting from 30 to 60cm spacings for canola in the northern region has potential to reduce seed, fertiliser and fuel costs at seeding and make stubble handling easier.

Graphic showing yield of narrow versus wide rows for hybrid and open-pollinated plant types at two seeding rates

Figure 1 Yield of narrow versus wide rows for hybrid and open-pollinated plant types at two seeding rates at Ben Cripps's farm.

Placing fertiliser only in the wide rows increases the concentration around seedlings, so growers may be able to drop compound fertiliser rates and reduce upfront costs. Another potential advantage is better airflow and fungicide efficacy when dealing with diseases such as sclerotinia.

These trials open the way to refine agronomic packages for wide rows and investigate the potential for reduced upfront costs by refining fertiliser and seed-rate recommendations.

This is important for the region as half of the Geraldton Port Zone canola was a Roundup Ready® hybrid in 2014 to control Group A and Group C resistant weeds. Keeping seed rates and costs down in low-yielding environments is important for maintaining production in these areas.

Growers involved in these trials also considered aspects other than yield to be an important factor in deciding to use wide rows. Reduced fuel costs at seeding (about 30 per cent), better stubble handling and improved crop safety of incorporated-by-sowing herbicides were all reasons given.

Future research will consider the use of wider row spacing in areas further south. 

More information:

Martin Harries, DAFWA,
08 9956 8553,
martin.harries@agric.wa.gov.au

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GRDC Project Code DAW00227

Region West