1. 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),

2. 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)

3. Hydrochar nanoparticles
Introduction | Material and Methods | Results and Discussion | Summary and Outlook
F. Bergius (1913) – HydroThermal Carbonization
Biomass → hydrochar + process water + gas + heat
Processing conditions: aqueous solution (acidic), °C, h
Carbon conversion efficiency ~ 90%
Hydrochar (HTC-biochar)
Lignite alike product
Energy production
Large specific surface area
Nutrient storage and buffering?
Porous structure Water storage?
Decomposition stability Carbon sequestration?
HTC
Hydrothermal carbonization (HTC): biomass conversion in aqueous solution (dilute acid) under moderate temperatures and resulting pressures for several hours. The resulting matter reportedly captures 100% of the carbon in a "biocoal" powder that could provide feedsource for soil amendment (similar to biochar) and further studies in economic nanomaterial production.
Lignite, often referred to as brown coal, is a soft brown fuel with characteristics that put it somewhere between coal and peat. It is considered the lowest rank of coal;
Hydrochar nanoparticles

4. Introduction | Material and Methods | Results and Discussion | Summary and Outlook
Hydrochar production conditions: 12 h, 190 °C
Hydrochar
made 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**
1.0
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.

5. Introduction | Material and Methods | Results and Discussion | Summary and Outlook
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

6. Hydrochar effect on seedling emergence and growth
Introduction | Material and Methods | Results and Discussion | Summary and Outlook
May:
Hydrochar effect on seedling emergence and growth
Growth stage:
DC 14
4-6 leaves
DC 12
2-4 leaves
DC 10
cotyledon
Beet pulp / N0
Hydrochar

7. Hydrochar effect on sugar beet yield and N content
Introduction | Material and Methods | Results and Discussion | Summary and Outlook
June harvest:
Hydrochar effect on sugar beet yield and N content
Hydrochar

8. Hydrochar effect on Soil Nmin (N-NO3 + N-NH4) and Leaf Area Index
Introduction | Material and Methods | Results and Discussion | Summary and Outlook
Hydrochar effect on
Soil Nmin (N-NO3 + N-NH4)
and Leaf Area Index

9. October harvest: Hydrochar effect on Beet N Uptake
Introduction | Material and Methods | Results and Discussion | Summary and Outlook
October harvest: Hydrochar effect on Beet N Uptake
and White Sugar Yield
Hydrochar
Hydrochar

10. Greenhouse trial Cambisol (100 mg N kg-1), 1 kg soil pot-1
Introduction | Material and Methods | Results and Discussion | Summary and Outlook
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
IfZ Goettingen, 2011
4 weeks of growing, 20 °C, % WHCmax

11. Hydrochar effect on single plant yield and N content
Introduction | Material and Methods | Results and Discussion | Summary and Outlook
Hydrochar effect on single plant yield and N content
Beet pulp
Beer draff
Draff
Control
Whole plants harvested after 4 weeks of growing
Hydrochar

12. Hydrochar effects (10-30 Mg ha-1) on
Introduction | Material and Methods | Results and Discussion | Summary and Outlook
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
N immobi- lization
→ Re-mineralization of N

13. Hydrochar (30 Mg ha-1) effects on soil properties: pH and CEC
Introduction | Material and Methods | Results and Discussion | Summary and Outlook
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?
Application, utilization

14. 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: /jeq