News

Time to consider nitrogen top up for canola

Media release : 12 June 2008

The Department of Agriculture and Food says it’s time for canola growers to consider a top up of nitrogen to boost canola yields.

Canola Research Officer with Centre for Cropping Systems, DAFWA, Mohammad Amjad said growers who wanted to top up nitrogen should consider doing so early in the season, within a few months of seeding.

“The yield potential for canola is generally established during the stem elongation stage, four to eight weeks after sowing, when the entire nitrogen should be applied,” Dr Amjad said.

“The amount of nitrogen required depends on the paddock history, soil types, crop rotation, fertiliser history (soil tests), season and the environment,” he said.

Dr Amjad said DAFWA research on canola nutrition assisted in providing guidance on canola nitrogen timing and application decisions.

“In low rainfall areas (up to 330mm) with a yield potential between 0.8-1.2T/HA, the required nitrogen application for canola averaged 45kg N/HA following the cereal phase compared to 30 kg N/HA following the legume or pasture rotation,” Dr Amjad said.

“In medium rainfall areas (330-460mm) with a yield potential between 1.2-1.8 T/HA, the required nitrogen application for canola averaged 65kg N/HA following the cereal phase compared to40 kg N/HA following the legume or pasture rotation.

“Similarly in high rainfall areas (460-600 mm) with a yield potential between 1.8-2.5 T/HA, the required nitrogen application for canola averaged 95 kg N/HA following the cereal phase, as compared to 65 kg N/HA following the legume or pasture rotation,” he said.

Department crop nutritionist, Ross Brennan said it was very profitable to apply fertiliser nitrogen to canola crops if the season is favourable.

“Our research, jointly funded by DAFWA and GRDC, has shown for soils that are deficient in both Phosphorous and Nitrogen, large grain yield responses occurred when these two elements were sufficiently applied,” Mr Brennan said.

“Applications of increasing rates of nitrogen decrease oil and increase protein concentration in canola grain,” Dr Amjad said.

“Growers are advised to assess their canola establishment and yield potential, and top-up nitrogen, preferably within four to five weeks for early maturity varieties (like CB Tanami) and within six to eight weeks for mid to late maturity varieties (like ATR Bravo),” he said.

“Growers in areas where the seasonal outlook is not so promising could consider the option of not topping up any more nitrogen, particularly when yield potential is lower.

“Profitability and economic return for applying additional nitrogen should be the prime consideration in making decisions,” he said.

For further information, contact Dr Mohammad Amjad at Northam (9690 2249) and Ross Brennan at Albany (9892 8474).

Mr Sivyer said the department supplied insect traps and pheromone baits free to participants. Monitoring group members were requested to check the traps in their orchards on Mondays during summer and report in.

“After checking and collation, Orchard Alert is sent out to all subscribers on Wednesday. The aim is to provide an early warning on pest numbers before they get out of control,” Mr Sivyer said.

“We always recommend monitoring before spraying. Growers should try and get away from calendar spraying because the seasons vary considerably, and it can mean an expensive waste of chemicals and fuel, as well as a likely turn-off for some consumers.”

Mr Sivyer said about 180 subscribers receive Orchard Alert, mostly orchardists, rural suppliers, industry personnel and some chemical company representatives.

The service operates from October to late February with extra issues when required. One recent issue warned about the need for bud swell and leaf fall sprays and likely problems of resistance developing with repeated use of the same fungicides.

“Bacterial canker, bacterial spot and peach leaf curl can cause heavy losses, but are controlled by copper-based sprays,” Mark Sivyer said.

“These can be either copper oxychloride or Bordeaux mixture containing different proportions of copper sulphate and lime, depending on the time of year. For light infections, three sprays from autumn to spring should be sufficient, but for a heavily infected orchard six sprays might be needed over the season.”
Full details of recommendations against orchard insects and diseases can be found on the department’s website at www.agric.wa.gov.au.

Anyone interested in contributing or subscribing to Orchard Alert should contact Mark Sivyer on msivyer@agric.wa.gov.au or call 9368 3157.

Media Contacts

Katrina Bonser/Lisa Bertram, media liaison

9368 3937 / 9368 3325