Balanced nutrition in Brassica

napus production with emphasis

on S fertilizer requirements

Better Crops, Better Environment … through Science

Rob Norton.

Regional Director ANZ

Thomas Jensen, IPNI Northern Great Plains

Vladimir Nosov, IPNI Southern & Eastern Russia

ARAB 17, Wagga Wagga, August 2011

Why S and why now?

• Less use of high S fuels so less S from atmosphere.

• Use of high analysis fertilizers containing little incidental S

• Increased crop yields creating a higher S offtake.

• Slower organic matter turnover with conservation tillage

• Fewer S-containing pesticides

McNeill et al, 2005, Soil Use & Managementt/km2

S deficiency in Australia

• History of S deficiency in

pastures.

• Deficiencies in canola first seen

in NSW at Lockhart.

• Soils naturally low in S & OM.

• Since 1990, reduced use of

single super – clear trend to

AP’s

• High demand for S by canola.

• Sulphate is mobile – leachable.

S removals and S balances

Crop N P K S S %

Canola 2 t/ha 60 10 14 10 0.50

Wheat 3 t/ha 63 9 11 4 0.14

• Current fertilizer rates would indicate input of 1-5 kg S

per ha

• Offtakes differ among crops (Reuter & Robinson)

Crop S content Cv% Data

Canola 0.37 13% Khan et al., IPL Dahlen

Wheat 0.17 12% NVT SE Aust.

Grain Nitrogen to Sulphur Ratios – a

retrospective for balanced nutrition

Randell et al, 1981, AJAR, 32, 203-212.

S RESPONSIVE

S UNRESPONSIVE

Inadequate N

N & S CO-LIMITED –

ADDED N OR S WILL

CORRECT TO 17:1

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

0.000 0.050 0.100 0.150 0.200 0.250 0.300 0.350 0.400

N %

S %

Slope ~7:1

Soil S levels – ANRA Audit 2001

• Nationally

11% < 5 mg/kg

• New South Wales

25% < 5 mg/kg

• Victoria

3% < 5 mg/kg

Draws on data from mid-1990’s

Requires revision and review – current IPNI ANZ project

KCl-40

(mg/kg)

Crop Pasture

<8 52% 43%

8-12 20% 30%

>12 28% 27%

2010 Soil S test values (top 10 cm) for Victoria, South

Australia, New South Wales (~1200 tests)

Soil S levels KCl40 – 2010 (Pre-sowing ie before May 2010)

Location and Soil Type

KCl 40 Wheat

(mg/kg)

KCl 40 Canola

(mg/kg)

<3 3 to 5 >5 <12 >12

Harden Red & Brown Loams 11% 33% 56% 80% 20%

Horsham Grey & Brown Clay Loams 23% 18% 59% 68% 32%

Maryborough Red & Brown Clay Loams 0% 8% 92% 74% 26%

Cummins Red & Brown Sandy Loams 12% 44% 44% 74% 26%

Moree Gray &Brown Clay/Clay Loams 17% 20% 63%

Dalby Gray &Brown Clay/Clay Loams 15% 23% 62%

Emerald Gray &Brown Clay Loams 27% 19% 54%

Gunnedah Gray &Brown Clay Loams 10% 26% 63%

Soil depth 0-10 – mobility of S in profiles, maybe need a deeper soil

test as routine – when request nitrate, also request sulphate.

Role of organic sulphur – should the budget include mineralised S.

Improving S nutrition

To apply 20 kg S/ha

• Gypsum (~200 kg/ha)

• Surface applied

• Variable quality

• Cheap (?)

• Ammonium sulphate (100 kg/ha)

• Fertilizer damage to seedlings (machinery)

• See http://anz.ipni.net/anz0042-en

Opener type and row spacing (cm)

Inverted T or similar narrow point/opener (2.5 cm spread)

Share or similar mixing point(7.5 cm spread)

15 22.5 30 15 22.5 30

Light (sandy loam) texture 40 20 10 175 90 75

Medium (loam/clay loam) texture 75 55 40 245 150 125

Heavy (clay) texture 125 95 80 325 210 180

R Gelderman, SDSU

J Laycock, IPL

C Dowling, Backpaddock P/L

Strategies for S

• Spread out the need through the whole rotation

– Higher S rates in the cereal phase (more tolerant of seed placed

fertilizer)

– Canola/Wheat/Barley – use 10/15/15 to meet total demand.

– Depends on soil type/S mobility

– Use high rates up front (eg gypsum)

– Elemental S

• +Bentonite

Banding fertilizer away from seedrow

• Particularly important for N and S

• (includes MAP)

• Band fertilizer away from seed

– Band 2-3 cm away

– Side or Side & Below

– Mid-row band

• P/K source in seed row.

Topdress S in-crop

• ammonium sulphate, potassium sulphate, ATS

• Where the plant can get it –

– Root zone – control release rates to avoid leaching

• In synchrony with plant demand – canola can recover

from nutrient stress – eg Canola

S

applied

Kg/ha

Sowing 5-6

Leaf

Buds

Visible

Stem

Elongati

on

10 1.73 1.62 1.56 1.41 LSD

40 2.15 2.26 2.11 2.19 0.43

Hocking et al., 1996

Alternative sources of SParticle Size µ % S oxidised

2 weeks 4 weeks

<75 80 82

75-125 61 81

125-175 36 68

175-400 15 36

400-840 5 14

840-2000 2 5

2000-4000 1 2

• S0 oxidation rapid with fine

particles

– Good for sulphate release

– Bad for handling

• Two new processes that

incorporate S0 into existing

products at manufacture

12:18:0:10

N:P:K:S

Up to 14% S

50:50 S0:SO4

Summary

• Care with S and N in-furrow with canola – especially light

soils, dry conditions, wide rows.

• Compared to cereal crops, canola requires a greater

supply of S – N:S 7:1 canola; 15:1 wheat

• Applying all the required S in the seed-row for canola is

difficult because of excess N coming from the ammonium

phosphate and ammonium sulphate portion of a possible

seed-row blend.

• There are alternative ways to supply sufficient S and

avoid excess N in the seed-row.