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.