High nitrogen supply alleviates reduced sugarbeet growth caused by
hydrochar application
Heinz-Josef Koch & Ana Gajić
Institute of Sugar Beet Research, Goettingen, Germany
2012 US Biochar Conference – Sonoma (CA), 29.07.-01.08.2012.
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Introduction | Material and Methods | Results and Discussion | Summary and Outlook
In Germany, increasing cultivation of energy crops and use of crop residues for energy production has considerably reduced the amount of crop residue left on arable fields
The German Federal Soil Protection Act stipulates that "the site-specific soil humus content must be preserved by the agricultural practices applied, in particular by an adequate supply of organic matter ...“
To prevent humus depletion of arable fields, alternative practices and concepts must be developed (e.g. biochar, hydrochar)
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F. Bergius (1913) – HydroThermal Carbonization Biomass → hydrochar + process water + gas + heat Processing conditions:
aqueous solution (acidic), 180 - 250 °C, 4 - 12 h Carbon conversion efficiency ~ 90%
Hydrochar (HTC-biochar) Lignite alike product
Energy production
Large specific surface areaNutrient storage and buffering?
Porous structureWater storage?
Decomposition stability Carbon sequestration?
HTC
Hydrochar nanoparticles
Introduction | Material and Methods | Results and Discussion | Summary and Outlook
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The aim of this study was to investigate the effect of hydrochar on sugar beet growth and mineral N (Nmin) availability
on typical German arable soils.
Introduction | Material and Methods | Results and Discussion | Summary and Outlook
Hydrocharmade from
Plant available nutrients -------- Other properties -----NNO3, NH4 PCAL KCAL MgCaCl2
Ct Nt C:N pH EC
[g kg-1] [%] [%] [ ] [ ] [mS cm-1]
Beet pulp 0.3 0.5 0.4 0.2 50.1 1.3 38.3 5.9 2.8
Draff** 0.4 1.0 0.3 0.5 54.4 3.5 15.5 5.3 2.3
* VDLUFA - horticultural substrates **Spent grains
Hydrochar production conditions: 12 h, 190 °C
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Introduction | Material and Methods | Results and Discussion | Summary and Outlook
Site Goettingen, 2010
Field trial (51 N, 10 E)
Luvisol (loessial), temperate climate (620 mm, ~9 °C)
2 factorial (split-plot, 4 replicates)
1. Hydrochar (H)
Control, Beet pulp, Draff
2. Nitrogen fertilization (N)
0, 50, 100, 150 kg N ha-1
Hydrochar 10 Mg ha-1 (dm)
Test crop: Sugar beet
(April – October)
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Beet pulp / N0
DC 10cotyledon
DC 122-4 leaves
DC 144-6 leaves
Introduction | Material and Methods | Results and Discussion | Summary and OutlookS
eedl
ing
emer
genc
e [%
]
0
20
40
60
80
100
Control Beet pulp Draffkg N ha-1:
DC 10 DC 12 DC 14
H ns | N ns | HxN ns
May:Hydrochar effect on seedling emergence and growth
Growth stage:
----------Hydrochar----------
7June harvest:
Hydrochar effect on sugar beet yield and N content
Introduction | Material and Methods | Results and Discussion | Summary and Outlook
Sin
gle
plan
t yi
eld
[mg,
dm
]
0
200
400
600
800
1000
N c
onte
nt [
% in
dm
]
0
4
6
8
10 Yield H ** | N ** | HxN **N content H ns | N ** | HxN ns
kg N ha-1:
Control Beet pulp Draff
cd
dd
a
b
bc bc bcb
----------Hydrochar----------
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Hydrochar effect on
Soil Nmin (N-NO3 + N-NH4)
Introduction | Material and Methods | Results and Discussion | Summary and Outlook
05. May 09. Jun 07. Jul 30. Sep
Nm
in 0
-90
cm [
kg N
ha-1
]
0
50
100
150
200
250
aa
b
ns ns *** nsSampling:
ControlBeet pulpDraff
Nmin 0-30 cm
28. Jun
12. Jul
26. Jul
09. Aug
24. Aug
06. Sep
Leaf
Are
a In
dex
[m2 m
-2]
0
1
2
3
4
ControlBeet pulpDraff
and Leaf Area Index
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October harvest: Hydrochar effect on
Beet N Uptake
Introduction | Material and Methods | Results and Discussion | Summary and Outlook
Adj
uste
d su
gar
yiel
d [M
g ha
-1]
0
10
11
12
13
Control Beet pulp Draffkg N ha-1
H ** | N ns | HxN **
aba
cb
cb
cb
cb
cb
c cb
cb
cba
cba
0 50100
150 0 50100
150 0 50100
150
Bee
t N
upt
ake
[kg
ha-1
]
0
50
75
100
125H ** | N ** | HxN ns
kg N ha-1:
Control Beet pulp Draff
B A B
--------Hydrochar-------- -------Hydrochar--------
and White Sugar Yield
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IfZ Goettingen, 2011
Greenhouse trial
Cambisol (100 mg N kg-1), 1 kg soil pot-1
Block design (4 replicates)
1. Hydrochar (H)
Control, Beet pulp, Draff
2. Nitrogen fertilization (N)
0, 100, 200 mg N kg-1 soil
Hydrochar 30 Mg ha-1 (dm)
Test crop: Sugar beet
Introduction | Material and Methods | Results and Discussion | Summary and Outlook
4 weeks of growing,20 °C, 40-80 % WHCmax
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Beet pulp
Beer draff
Beet pulp
Draff
ControlWhole plants harvested after 4 weeks of growing
Sin
gle
plan
t yi
eld
[mg,
dm
]
0
200
400
600
800
1000
N c
onte
nt [
% in
dm
]
0
2
4
6
8
10
c
e e
a
cd
de
b
e
e
Control Beet pulp Draff
mg N kg-1:
Yield: H ** | N ** | HxN **
ab
c
e
b
d
b
c
e
N content: H ** | N ** | HxN *
a
Hydrochar effect on single plant yield and N content
Introduction | Material and Methods | Results and Discussion | Summary and Outlook
--------Hydrochar--------
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Hydrochar effects (10-30 Mg ha-1) on
Early sugar beet growth: Seedling emergence and establishment was not affected Seedling growth was significantly reduced at low N supply Increased N supply partly (field) or completely (greenhouse)
compensated for stunted early growth (toxic compounds?) Early growth reduction was more severe with hydrochar
from beet pulp (C/N 38) compared to draff (C/N 16)
Final sugar beet yield and quality: No yield decrease due to hydrochar, when N supply was adequate Beet pulp hydrochar (but not draff) reduced yield at low N supply Draff hydrochar slightly increased N uptake at low N supply
Introduction | Material and Methods | Results and Discussion | Summary and Outlook
N immobi-lization
→ Re-mineralization of N
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Mean residence time (microcosm study):
Wheat straw (1 y) < Hydrochar (5-8 y) <<< Biochar (4x1012 y)
Hydrochar (30 Mg ha-1) effects on soil properties:
pH and CEC
Aggregate stability
Water holding capacity
Open questions
Optimum HTC conditions: feedstock, temperature, time?
Optimum crop and time of application?
Phytotoxicity?
C balance, energy balance, GHG emission?
Introduction | Material and Methods | Results and Discussion | Summary and Outlook
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Thanks for Your attention!
Gajić, A. & Koch H.-J. (2012): Sugar Beet (Beta vulgaris L.) Growth Reduction Caused by Hydrochar Is Related to Nitrogen Supply. J Environ Qual doi:10.2134/jeq2011.0237.