Canola 4R nutrient management lessons from Australia

Rob Norton http://anz.ipni.net @ANZIPNI

Be#er  Crops,  Be#er  Environment  …  through  Science  US Canola Association Research Conference, Long Beach CA, October 02, 2014.

Spring types grown over winter •  WA – leached

acid sands,1.25 Mha

•  SA – hypercalcic alkaline 0.3 Mha

•  Vic & NSW– verto(i)sols, chromosols,1.0 Mha

40 kHa in 1990

Development – time & photothermal time.

May June July/ Aug Sep Oct Nov

“Standard” fertilizer practice

•  Common strategies –  P applied as MAP/DAP – banded at seeding –  N applied as split dressings as urea/UAN/AmS

•  Regional strategies –  K applied at seeding as MOP – banded (WA) –  S applied in a range of strategies (light soils)

•  as gypsum (+/- lime) pre-seeding •  S supplemented MAP at seeding •  AmS topdressed at stem elongation •  UAN/AmS fluids applied at stem elongation

•  Specific micronutrient issues (soil type/year) –  B on light soils in wet years. –  Mn, Mo on acid sands, Mn in high carbonate soils.

+P -P

Determine the right rate – 2 approaches

•  Soil test – Colwell P (Bicarb. extr.) (0-10cm) + PBI –  Canola critical soil test range – 16-19 mg/kg –  Wheat CSTR a little higher

•  Wheat P strategy adopted –  Replacement + Soil “Demand” –  P: 5672 ±1125 mg/kg (0%MC)

2.5 t/ha canola = 14 kg P + 1-4 kg P = 75 kg MAP/DAP

Lesson 1: Safe cereal AP rates are not safe for canola.

Seed damage – Using DAP/Urea

Safe rates

20 cm 30 cm

DAP MAP DAP MAP 125 mm Share 85 140 60 90

Spear Point 30 45 20 31

Row Spacing

Fertilizer Spread

SBU = %FS/RS

http://anz.ipni.net/articles/ANZ0042-EN Based on RH Gelderman SDSU Decision Aid

Lesson 2 – Get N right

N Rate (kg/ha)

Seed Yield (t/ha)

Total DM (t/ha)

Water Use (mm)

WUE (kg/ha/mm)

Soil Evapn (mm)

0 1.62 5.24 307 5.3 128 70 2.47 8.83 349 7.1 112

140 2.50 8.67 344 7.3 91 210 2.82 9.52 335 8.4 87

lsd (p<0.05) 0.56 1.66 36 - -

N Rate (kg/ha)

Seed Yield (t/ha)

Total DM (t/ha)

Oil % Oil Yield $/ha*

0 1.62 5.24 46.3 0.75 513 70 2.47 8.83 45.4 1.01 720

140 2.50 8.67 42.1 1.05 770 210 2.82 9.52 41.0 1.15 855

lsd (p<0.05) 0.56 1.66 2.1 - -

•  N increases yield •  N increases WUE •  N decreases oil%

* $300/t ±1.5% oil bonus 42%

Lesson 2: Right rate & time Plan, review & reassess N •  N budget – Yield * 40 * 2 - supplies

–  N @ sowing + Mineralisation.

•  What is the yield potential now? –  Modelled/estimates/seasonal

•  25 mm of rain –  0.3 t/ha canola –  0.45 t/ha wheat

•  To meet that extra yield = 18-20 kg N. •  Is N limiting Lake Bolac – September Yield Prophet® estimate.

Lesson 3: For us – there is little penalty of delaying N?

Rate Timing

All predrilled

Split early*

Split late*

TD early

TD late Nil N LSD

(5%) High (90 kg N) 2.11 2.10 2.16 2.30 1.92

1.36 0.33 Moderate (50 kg N) 1.80 2.03 1.69 2.11 1.63

Wallup Ag Group, 2011

Source

Time Place

Rate

Growth, Variety and N uptake/demand canola, 4-5 leaf

50 kg N/ha (soil+fert) adequate to get crops through to 4-5 leaf stage

Lesson 4: Sulfur - be alert but not alarmed

•  First seen in NSW on red-brown earths.

•  Soils naturally low in S (and OM).

•  Reduced use of single super.

•  S removal by canoa –  ~4 kg S/t (cf 10)

•  Organic S mineralisation –  N:S ~8:1 –  50 kg N ~ 6 kg S

•  Reviewing S responses T Jensen IPNI

A Good, Incitec Pivot

Right place & right time for sulfur

•  Like N – synchronize S supply with plant demand •  Canola has good ability to recover from early S stress •  Transient/Real S deficiency on light soils

–  500 kg/ha gypsum (mined/pit) –  Top dressed with AmS common – blended with urea.

S applied Kg/ha

Sowing 5-6 Leaf

Buds Visible

Stem Elongati

on 10 1.73 1.62 1.56 1.41 LSD

0.43 40 2.15 2.26 2.11 2.19 Hocking et al., 1996

Balance N & S – ratio more like 10:1 rather than 7:1

Question S requirements & balancing S with N

Lesson 5: Canola nutrition and the oil of snakes

•  Canola relatively more efficient than wheat at accessing soil Zn (Brennan and Bolland 2002)

•  No confirmed Cu deficiency for canola reported – probably able to access Cu efficiently as well.

B Holloway SARDI

•  Mo responses seen in sandy acidified gravel soils in Western Australia. Liming or sodium molybdate?

Boron Deficiency/Toxicity

P Parker NSW DPI

Toxic

Deficient

Canola B *6

Wheat B

Manganese

•  Manganese toxicity –  pH < 5.5 & water logging

•  Mn deficiency –  pH.8.5 (>60% CaCO3) –  Highly leached sands

•  No impaired Mn in RR types

D McCaffery NSW DPI

Seed Mn mg/kg

Covn 36.2 Imi Tol 40.8

RR 36.4 TT 37.0

LSD (p<0.05) 1.7

Canola Nutrition

•  P largely as for cereals •  Seedbed damage potential •  N to match unfolding yield •  Little penalty from early N stress •  S more important than for cereals but maybe overstated •  B and Mo – show regional responses •  Cu, Mn and Zn are regional issues but canola more able

to access soil supplies than cereals •  Tissue testing best strategy for potential micronutrient

response.

International Plant Nutrition Institute •  http://www.ipni.net

•  http://anz.ipni.net