High nitrogen supply alleviates reduced sugarbeet growth caused by hydrochar application

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), 29.07.-01.08.2012.

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. Introduction | Material and Methods | Results and Discussion | Summary and Outlook • F. Bergius (1913) – HydroThermalCarbonization • Biomass → hydrochar + process water + gas + heat • Processing conditions:aqueoussolution (acidic), 180 - 250 °C, 4 - 12 h • Carbon conversion efficiency ~ 90% • Hydrochar (HTC-biochar) • Lignite alike product • Energy production • Large specific surface area • Nutrient storage and buffering? • Porous structureWater storage? • Decomposition stability Carbon sequestration? HTC Hydrochar nanoparticles

4. Introduction | Material and Methods | Results and Discussion | Summary and Outlook The aim of this study was to investigate the effect of hydrochar on sugar beet growth and mineral N (Nmin) availabilityon typical German arable soils. • Hydrochar productionconditions: 12 h, 190 °C

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) Introduction| Material and Methods | Results and Discussion | Summary and Outlook Site Goettingen, 2010

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

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

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

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

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 Introduction| Material and Methods| Results and Discussion| Summary and Outlook IfZ Goettingen, 2011 4 weeks of growing,20 °C, 40-80 % WHCmax

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

12. 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 hydrocharfrom 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. 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?

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 Qualdoi:10.2134/jeq2011.0237.