Inoculation Technologies to Improve the Nodulation of ... - Lupins.org

DEPARTMENT OF
PRIMARY INDUSTRIES
Inoculation Technologies to Improve the
Nodulation of Lupins and other Grain
Legumes in South-eastern Australia
Dr Matthew Denton
Department of Primary Industries,
Rutherglen

DEPARTMENT OF
PRIMARY INDUSTRIES
Outline
• The importance of legumes to farming systems
• Inoculant types in the Australian system
• Efficacy of liquid and granular inoculants
• Potential advantages of soil-applied inoculants
2

DEPARTMENT OF
PRIMARY INDUSTRIES
Australian agriculture is highly
reliant on nitrogen inputs
Nitrogen fertilisers - the
single most energy
expensive input in
agriculture
accounts for 35-68% of
total on-farm energy
use
Chen et al. 2008 Aust J Soil Res 46, 289-301

DEPARTMENT OF
PRIMARY INDUSTRIES
Energy Efficiency of Fertiliser vs Legume N
Energy intensive
30 GJ t - 1 NH 3
4 kg CO 2 emitted / kg
N produced
Photosynthetically-
driven N fertiliser
Effectively no CO 2
emission

DEPARTMENT OF
PRIMARY INDUSTRIES
N provided by lupins
Crop type
Mean N
balance
(kg N/ha)
Range
(kg N/ha)
Ref
Lupin 88 70-107 Evans 2001
Lupin 78 (-29) -247 Evans 1987,
1989
Lupin 97 174-177 Rochester
1998
Lupin 65 32 - 96 Unkovich
1994
• In addition, 30% of Total plant N is BG at harvest
McNeill et al. 2008 Plant & Soil, 302:297-

DEPARTMENT OF
PRIMARY INDUSTRIES
Peat Inoculants
• Industry standard
for Australia
• High quality
• >10 9 cells g -1 peat
• Applied as a slurry
or a liquid

DEPARTMENT OF
PRIMARY INDUSTRIES
Granular Inoculants
Granular inoculants
• Introduced into the Australian market for ~5 years
• Carriers: peat, or clays (usually bentonite, attapulgite
• Non-sterile formulations (unlike peat slurries)

DEPARTMENT OF
PRIMARY INDUSTRIES
Freeze-dried inoculants
Applied as:
1) slurry to
seed, or
2) liquid into
furrows

DEPARTMENT OF
PRIMARY INDUSTRIES
How do granular and liquid
inoculants differ to peat slurries?
• Peat slurry inoculants are applied to SEED
• Granules and liquid inoculants are applied to SOIL
• Soil inoculation:
1. Avoids incompatibility with seed toxins (fungicides, insecticides)
2. Avoids the need to inoculate seed
3. No time dependency when unfavourable conditions disrupt
sowing
4. Potential for dry sowing conditions
9

DEPARTMENT OF
PRIMARY INDUSTRIES
Seed inoculation Soil inoculation
Peat inoculant
on the seed
Granular
inoculant in
the seed row
Few large nodules
close to the crown
Several medium
nodules on
crown and
lateral roots
Slide courtesy of Newton Lupwayi

DEPARTMENT OF
PRIMARY INDUSTRIES
Chickpeas (Kyei-Boahen et al., 2001)
Treatment
Nodule dry weight (mg/plant)
Crown Lateral Total
Control 0.0 3.0 3.0
Liquid 9.5 16.0 25.5
Peat 193.3 70.8 264.0
Granular 80.3 163.0 243.3
Slide courtesy of Newton Lupwayi

DEPARTMENT OF
PRIMARY INDUSTRIES
Chickpeas (Kyei-Boahen et al., 2001)
Treatment %Ndfa Grain yield
(t/ha)
Control 17.2 1.22
Liquid 19.9 1.52
Peat 49.1 1.81
Granular 56.9 1.81
Slide courtesy of Newton Lupwayi

DEPARTMENT OF
PRIMARY INDUSTRIES
What is the efficacy of granular and
liquid inoculants in Australia?
•37 experiments over 5 years in Vic, SA and
southern NSW
•Efficacy of granular and liquid inoculants tested
•Lupins, faba beans, peas, chickpeas and lentils
13

DEPARTMENT OF
PRIMARY INDUSTRIES
Site distribution

DEPARTMENT OF
PRIMARY INDUSTRIES
What difference does soil
inoculation make?
15

DEPARTMENT OF
PRIMARY INDUSTRIES
Crown nodulation,
typical of peat slurry
inoculants
Crown and Deep
nodules from effective
granular and liquid
inoculants
10 mm
Chickpeas, Inverleigh, 2007

17
Liquid inoculant seed
Liquid injection
DEPARTMENT OF
PRIMARY INDUSTRIES
Nodule number
18
15
12
9
6
3
Nodule number (plant -1 )
Uninoculated
Peat inoculant
Granules B 5
Granules B 10
Granules B 10 Undersown
Granules A 5
Granules A 10
Granules A 10 Undersown
0
Lupins, Inverleigh 2006
Denton, Pearce et al. in prep.

WU425 peat slurry
WU425 water inject
DEPARTMENT OF
PRIMARY INDUSTRIES
Poorly responsive sites
700
600
500
400
300
200
100
Nodule mass (mg per plant)
0
uninoculated
bentonite granules
attapulgite granules
attapulgite granules at 50 mm
Freeze dried on seed
Freeze dried in furrow
80 units N / ha
WSM4024 water inject
WSM4024 peat slurry

DEPARTMENT OF
PRIMARY INDUSTRIES
Response of Inoculants
Log
nodulation
(treatments)
Log background nodulation
(nodulation by uninoculated

DEPARTMENT OF
PRIMARY INDUSTRIES
Chickpea Faba bean Lentil Lupin Field pea
Peat slurry
Peat
granules
Attapulgite
granules
Bentonite
granules

DEPARTMENT OF
PRIMARY INDUSTRIES
% Plant nodulation
Data from 37
field trials
separated by
soil rhizobial
population;
black columns
small soil
populations;
white columns
large
populations
100
80
60
40
20
% Plants nodulated
Uninoculated
Bentonite 10 kg / ha
Bentonite 5 kg / ha
Attapulgite 10 kg / ha
Attapulgite 5 kg / ha
Peat granules 10 kg / ha
0
Peat granules 5 kg / ha
Peat slurry on seed

DEPARTMENT OF
PRIMARY INDUSTRIES
Results
(a)
White
symbols –
bentonite
Grey
symbols –
attapulgite
granules
Black
symbols –
peat
granules
% Plant nodulation
100
80
60
40
20
0
10 3 10 4 10 5 10 6 10 7 10 8 10 9 10 10
Rhizobial concentration in granules (number of rhizobia g -1 granule)
Denton, Pearce, Ballard, Mutch, Norng, Hannah, Slattery,
unpublished data

DEPARTMENT OF
PRIMARY INDUSTRIES
Results
White
symbols –
bentonite
Grey
symbols –
attapulgite
granules
Black
symbols –
peat
granules
% Plant nodulation
100
80
60
40
20
0
10 3 10 4 10 5 10 6 10 7 10 8 10 9 10 10
Rhizobial concentration in granules (number of rhizobia g -1 granule)
(b)
Denton, Pearce, Ballard, Mutch, Norng, Hannah Slattery, unpublished
data

DEPARTMENT OF
PRIMARY INDUSTRIES
Inoculant potential
• Peat inoculant with 10 9 rhizobia applied at
250g / 100 kg seed and sown at 100 kg seed
/ ha = 2.5 x 10 11 rhizobia / ha
• Granular inoculant with 10 7 rhizobia applied
at 10 kg / ha = 1 x 10 11 rhizobia / ha

DEPARTMENT OF
PRIMARY INDUSTRIES
Field Response
Granular
inoculant
Peat
inoculant
Nil
Faba beans, Yalla-Y-Pora, 2005

DEPARTMENT OF
PRIMARY INDUSTRIES Grain yield
3
2
1
Grain yield (tonnes ha -1 )
Uninoculated
Peat inoculant
Granules B 5
Granules B 10
Granules B 10 Undersown
Granules A 5
0
Granules A 10
Granules A 10 Undersown
Faba beans, Ararat 2005

DEPARTMENT OF
PRIMARY INDUSTRIES
Grain N
250
Grain nitrogen (kg N ha -1 )
200
150
100
50
0
0 1 2 3 4
Nodule score (plant -1 )
Faba beans, Ararat 2005

DEPARTMENT OF
PRIMARY INDUSTRIES
Conclusions
• Soil inoculants provide an option for inoculation
when seeds contain fungicides / pesticides
• Granular inoculants provide an option for inoculation
in dry soil environments
• Liquid inoculants are as effective as peat slurry
inoculants
• Granular inoculants can be as effective as peat
slurry inoculants, but require >10 7 cells g -1 inoculant

DEPARTMENT OF
PRIMARY INDUSTRIES
Acknowledgments
•The Grains Research and Development Corporation
and DPI for funding this work through the National
Rhizobium Program
•Bernadette Carmody and David Pearce - technical
assistance
•Ross Ballard, Lesley Mutch and Jo Slattery -
collaborators
•Murray Hannah and Sorn Norng - statistical assistance
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