Silicon fertilization experiments in Vietnam
Anika Marxen, Thimo Klotzbücher, Doris Vetterlein, Reinhold Jahn, Nguyen
Manh, Nguyen Van Sinh, Le Thi Dieu Xuan, Le Quoc Cuong, Ho Van Chien
Questions
Effects of Si fertilization on:
• Si uptake?
• resistance against pests?
• rice growth?
• cycling of other nutrients?
• Strategies of fertilization
Methods
Plot experiment in Vinh Phuc (Jan – May 2013):
• Si uptake by plants
• Biomass production and yield
• Uptake of other essential nutrient
Si fertilizer
Laboratory experiment
(Jan 2014 – present):
• Effects of straw recycling on Si supply
• Strategy of fertilization?
Crop
residues
Plantavailable Si
Decomposition
Methods
Plot experiment in Tien Giang
(Nov 2013 – Feb 2014, Feb 2014 - …)
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•
•
•
•
Si uptake by plants
Biomass production and yield
Uptake of other essential nutrient
Effects on pests and diseases
Long-term study
Fertilization with silica gel
•
•
•
•
•
•
Readily dissolvable
No effect on soil pH
No nutrition with other nutrients
No toxic elements
produced for industrial use
expensive (30,000 VND per kg)
Silica gel: amorphous SiO2 * nH2O
Fertilization experiment in Vinh Phuc (VN_2)
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•
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•
3 Treatments
5 Replicates
5 paddy fields
Plot size: 2m x 2m
Paddy
0t
Si ha-1
0.4 t
Si ha-1
FControlContol
January 24th, 2013
May 17th, 2013
17.3 t
Si ha-1
Results – Si uptake by plants
Si in straw
14
6
critical
value a
b
12
Si (% of DM)
10
8
14
c
12
Si (% of DM)
Si in full sight (grains and hulls)
10
8
6
4
4
2
2
0
0
Control
0.4 t Si/ha 17.3 t Si/ha
a
Control
a
b
0.4 t Si/ha 17.3 t Si/ha
Results - Straw production and yield
8
Straw production
Grain yield
8
4
ab
a
b
2
Grains (t ha-1 DM)
6
-1
Straw (t ha DM)
b
6
a
a
4
2
0
0
Control
0.4 t Si/ha 17.3 t Si/ha
Control
0.4 t Si/ha 17.3 t Si/ha
 Grain yield increase by 50% (17.3 t Si ha-1)
Results – Nutrient concentration in straw normalized to C
a
P
12
a
a
10
mg P g-1 C -1
a
20
80
a
a
a
K
a
a
60
8
6
4
10
40
20
2
0
0
0.4 t Si/ha 17.3 t Si/ha
0.4 t Si/ha 17.3 t Si/ha
Mg
10
8
0
Control
a
6
20
18
ab
Control
ab
16
b
4
2
mg Ca g-1 C -1
Control
mg Mg g-1 C -1
mg N g-1 C -1
30
N
mg K g-1 C -1
40
Ca
a
b
14
12
10
8
6
4
2
0
0
Control
0.4 t Si/ha 17.3 t Si/ha
Control
0.4 t Si/ha 17.3 t Si/ha
0.4 t Si/ha 17.3 t Si/ha
Results – Nutrient concentration in full sight normalized to C
N
a
a
a
10
mg P g-1 C -1
a
30
20
10
P
a
0
a
4
6
4
a
a
8
6
2
0
0.4 t S/ha 17.3 t Si/ha
a
1,0
mg Ca g-1 C -1
2
Control
Ca
1,2
3
a
a
a
0,8
0,6
0,4
1
0,2
0,0
0
Control
a
4
Control
Mg
a
10
8
0.4 t S/ha 17.3 t Si/ha
a
12
0
Control
K
14
2
mg Mg g-1 C-1
mg N g-1 C -1
40
12
mg K g-1 C -1
50
0.4 t S/ha 17.3 t Si/ha
Control
0.4 t S/ha 17.3 t Si/ha
0.4 t S/ha 17.3 t Si/ha
Straw decomposition experiment
Straw with
different Si
levels
Decomposition
(+/-fauna)
(Anja Schmidt &
Martin Schädler)
Release of Si
and other
nutrients
Plant nutrient
uptake and
rice growth
Fertilization experiment in Tien Giang (VN_4)
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•
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

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4 Treatments: 0 t Si ha-1, 0.1 t Si ha-1 , 0.4 t Si ha-1, 1.5 t Si ha-1
5 Replicates
Plot size: 8m x 8m
plots with bunds within one paddy (randomized block design)
Long-term effect of Si fertilization
Assessment of pests and diseases
Baitplant experiment  Christina Sann
Effects on aquatic invertebrate decomposers  Stefan Hotes
November 30th, 2013
December 4th, 2013
Harvest
Conclusions and outlook
• In Vietnam, Si fertilization increases Si uptake and crop yields
Before large-scale Si fertilization…
• Further studies on the uptake of other nutrients than Si are
necessary
• Results concerning decomposition must be considered
• Fertilization strategy must be developed from the long-term
study
• Economical feasibility must be tested
Thanks
• All field workers
• All farmers
• Alexandra Boritzki
• Susanne Horka
• Alexey Prays
• Thomas Redtmann
• Josef Settele
• BMBF
…and for your attention!