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.
Introduction | Material and Methods | Results and Discussion | Summary and Outlook
2
 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)
Introduction | Material and Methods | Results and Discussion | Summary and Outlook
3
 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
HTC
Hydrochar nanoparticles
 Large specific surface area
Nutrient storage and
buffering?
 Porous structure
Water storage?
 Decomposition stability
Carbon sequestration?
Introduction | Material and Methods | Results and Discussion | Summary and Outlook
4
Hydrochar production conditions: 12 h, 190 °C
Plant available nutrients
Hydrochar
N
made from
NO3, NH4
P
CAL
K
CAL
Mg
CaCl2
[g kg-1]
-------- Other properties ----Ct
Nt
C:N
pH
EC
[%]
[%]
[]
[]
[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
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
5
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)
Site Goettingen, 2010
Introduction | Material and Methods | Results and Discussion | Summary and Outlook
6
May:
Hydrochar effect on seedling emergence and growth
H ns | N ns | HxN ns
DC 10
DC 12
DC 14
Growth stage:
DC 14
4-6 leaves
80
60
DC 12
2-4 leaves
40
20
DC 10
cotyledon
Control
Beet pulp
50
10
0
0
50
10
0
0
-1
kg N ha :
50
10
0
0
0
Seedling emergence [%]
100
Draff
----------Hydrochar----------
Beet pulp / N0
Introduction | Material and Methods | Results and Discussion | Summary and Outlook
7
June harvest:
Hydrochar effect on sugar beet yield and N content
Yield H ** | N ** | HxN **
N content H ns | N ** | HxN ns
10
d
800
8
cd
600
bc
b
400
bc bc
b
6
a
200
4
Control
Beet pulp
0
50
10
0
0
0
50
10
0
0 -1
kg N ha :
Draff
----------Hydrochar----------
N content [% in dm]
d
0
50
10
0
Single plant yield [mg, dm]
1000
Introduction | Material and Methods | Results and Discussion | Summary and Outlook
8
Hydrochar effect on
Soil Nmin (N-NO3 + N-NH4)
and
4
150
b
100
a
a
50
-2
200
3
2
Control
Beet pulp
Draff
Nmin 0-30 cm
Leaf Area Index [m m ]
-1
Nmin 0-90 cm [kg N ha ]
250
0
Sampling: 05. May
ns
Leaf Area Index
2
1
Control
Beet pulp
Draff
0
09. Jun
ns
07. Jul
***
30. Sep
ns
.
28
n
Ju
l
12
u
.J
26
u
.J
l
g
09
u
.A
g
24
u
.A
06
e
.S
p
Introduction | Material and Methods | Results and Discussion | Summary and Outlook
9
October harvest: Hydrochar effect on
Beet N Uptake
and
White Sugar Yield
13
H ** | N ** | HxN ns
H ** | N ns | HxN **
50
0-1
kg N ha :
B
A
B
0 50 00 50
1 1
Control
0 50 00 50
1 1
Beet pulp
0 50 00 50
1 1
Draff
--------Hydrochar--------
11
c c c c
b
b b
10
0
kg N ha-1
Control
c c
b b b
a a
Beet pulp
c c c c
b b b b
a a
0
50
10
150
0
75
12
0
50
10
150
0
100
0
50
10
150
0
-1
Beet N uptake [kg ha ]
-1
Adjusted sugar yield [Mg ha ]
125
Draff
-------Hydrochar--------
Introduction | Material and Methods | Results and Discussion | Summary and Outlook
10
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
4 weeks of growing,
20 °C, 40-80 % WHCmax
IfZ Goettingen, 2011
Introduction | Material and Methods | Results and Discussion | Summary and Outlook
11
Hydrochar effect on single plant yield and N content
Control
Whole plants harvested after 4 weeks of growing
Yield: H ** | N ** | HxN **
N content: H ** | N ** | HxN *
e
800
10
e
e
e
de
600
400
200
6
cd
c
e
e
d
c
ab
0
0 0
-1 0
mg N kg : 10 20
Control
8
b
a
b
c
b
2
Beet
Beetpulp
pulp
Draff
Beer draff
a
0 00 00
1 2
Beet pulp
4
N content [% in dm]
Single plant yield [mg, dm]
1000
0 00 00
1 2
Draff
--------Hydrochar--------
0
Introduction | Material and Methods | Results and Discussion | Summary and Outlook
12
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)
N
immobilization
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
→ Re-mineralization of N
Introduction | Material and Methods | Results and Discussion | Summary and Outlook
13
 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?
Thanks for Your attention!
14
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.