Timing of nitrogen in low rainfall canola, Ogilvie 2014 trial report

Page last updated: Wednesday, 27 March 2019 - 10:37am

In general, as long as nitrogen is applied within eight weeks of sowing, there is no yield penalty.

How canola responds to nitrogen applied later than eight weeks has not been widely researched. Similarly how new generation canola such as Roundup ready (RR) hybrids respond to nitrogen has not been widely tested, particularly in low and medium rainfall areas.

Summary (key messages)

  • Pioneer 43Y23 (RR) had higher grain yield, oil yield (kg/ha) and gross margins, than Sturt (TT).
  • Grain yield responded to applied nitrogen up to approximately 40kg N/ha.
  • Both varieties responded similarly to applied nitrogen with no variety x N rate interaction for grain yield.
  • Oil yield and gross margins did not respond to applied nitrogen.
  • Timing of nitrogen application did not alter the response to nitrogen of both varieties for grain yield, oil percentage, oil yield or gross margin.

Aim

To investigate the response to changing the nitrogen rate and changing the time of application. Canola yield and oil will be measured and RR hybrids will be compared with open-pollinated TT types (OP TT).

Trial details

  • Property: Northern Agri Group site at Ogilvie
  • Growing season rainfall (GSR) (April to September): 263mm, long term average (LTA) (from 1974 onward): 275mm.
  • Soil type: yellow sandy earth (0.57% organic carbon), estimated to be 58kg N/ha available in paddock from soil and plant residues
  • Paddock rotation: wheat 2013, lupin 2012, wheat 2011
  • 22 treatments: two cultivars (Sturt TT [TT open-pollinated variety] and Pioneer 43Y23 RR [RR hybrid variety]) x 11 N treatments (kg N/ha) with timing spread between seeding, and up to 12 weeks after sowing (see Table 2)
  • Three replicates
  • Sowing date: 29 April
  • Seeding rate: target density 30 plants/m2 - Sturt TT 2.4kg/ha, Pioneer 43Y23 RR 1.5kg/ha
  • Basal fertiliser: 80kg/ha of BigPhos + Mn at seeding, 120kg MOP/ha + 400 Gypsum top-dressed over whole site on 3 June.
Table 1 Treatment details
Treatment Name Seeding 8WAS 12WAS Total N
1 Nil 0 0 0 0
2 10N Seeding 10 0 0 0
3 30N in 8 weeks 10 20 0 30
4 50N in 8 weeks 10 40 0 50
5 70N in 8 weeks 10 60 0 70
6 10N seeding and 20N 12WAS 10 0 20 30
7 10N seeding and 40N 12WAS 10 0 40 50
8 10N seeding and 60N 12WAS 10 0 60 70
9 30N in 8 weeks and 10N 12WAS 10 20 10 40
10 30N in 8 weeks and 20N 12WAS 10 20 20 50
11 30N in 8 weeks and 40N 12WAS 10 20 40 70

Assumptions used in gross margins

  • Oil bonus +/- 1.5% per unit of oil (%) either side of 42%, with no oil ceiling.
  • Additional costs such as seeding, harvest, insecticides assumed to be $229/ha.
  • Nitrogen costs $1.33/kg or $1.5/L, application costs $8/ha
  • RR costs – seed $76/ha, herbicides $47/ha, grain worth $513/t (five year decile price)
  • TT costs – seed $5/ha, herbicides $56/ha, grain worth $535/t

Results

Pioneer 43Y23 (RR) had higher grain yield, oil yield (kg/ha) and gross margins, than Sturt (TT). Both varieties produced similar oil percentages.

Table 2 Grain yield, oil %, oil yield and gross margin of two canola varieties at Ogilvie in 2014
  Pioneer 43Y23RR Sturt P LSD
Grain yeild (kg/ha) 1785 1127 <0.01 81
Oil % 43.4 44.6 0.098 1.8
Oil Yield (kg/ha) 778 502 <0.01 30
Gross Margin ($/ha) 550 253 <0.01

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Response to N

Grain yield responded to applied nitrogen up to approximately 40kg N/ha, attaining yields of 1512t/ha. Both varieties responded similarly to applied nitrogen with no variety x N rate interaction for grain yield.Maximum oil percentage was produced at 30kg N/ha.

Oil yield and gross margins did not respond to applied nitrogen.

Table 3 Grain yield, oil % and gross margin response to nitrogen at Ogilvie in 2014
N GY Oil GM
0 1392 44.6 433
10 1420 44.8 431
30 1387 45.0 391
40 1512 43.8 423
50 1480 43.6

400

70 1493 43.3 382
N - - -
P 0.017 0.015 0.244
LSD 91 1.2 ns
N x variety - - -
P 0.846 0.198 0.841

Timing of nitrogen

Nitrogen was applied at eight or 12 weeks or split between eight and 12 weeks. We found the timing of nitrogen application did not alter the response to nitrogen of both varieties for grain yield, oil percentage, oil yield or gross margin.

Conclusion

RR variety Pioneer 43Y23RR outperformed the TT variety Sturt at Ogilvie in 2014.

While canola growth and yield responded to applied N the scale of the response was insufficient to produce an economic response.

Acknowledgements

This trial (14CH27) is one of a series conducted throughout Western Australia as part of the GRDC/DPIRD co-funded project Tactical Break Crop Agronomy in Western Australia. Thanks to the local RSU for trial management. Stephanie Boyce and Jo Walker provided technical assistance to ensure all treatments and measurements occurred in a timely and accurate fashion.

Contact information

Martin Harries
+61 (0)8 9956 8553
Mark Seymour
+61 (0)8 9083 1143
Sally Sprigg
+61 (0)8 9081 3153