September 5th, Höör, Sweden - SGC · • M&M and first Results ... 100 150 200 250 300 350 400 0 5 10 15 20 25 30 spec. spec. ... • Storage of all “mixtures”/samples for 32

Effects of spreading of fermentation residues on the soil physics and soil functions

September 5th, Höör, Sweden

M. Bölter, A. Hold, D. Holthusen, R. Horn, S. Ohl, A. Voelker, E. Hartung****Institute of Agricultural Engineering ‐ Kiel University

Agenda:• Motivation/Focus• Project Flow Chart• M&M and first Results• Conclusions

This joint research project is funded by:Central German coordinating institution in the field of renewable resources (R&D Funding programme for Renewable Resources)

Motivation/Focus

Substrate/Ensiling/Fermentation:• new substrates / mixture of substrates• ensiling losses• efficiency & kinetics of fermentation

Soil‐Microorganisms /‐nutrients/Microorganism activity:• “substrate enrichment” by fermentation• influence on microorganism activity/community• “fertiliser” threshold definition

Soil‐Properties/‐Structure/‐Characterisation:• decrease of pH (sludge) & acidification• alternation of soil sorption / surface properties • destabilisation & reduction of soil structure

substrates:• Inoculum• Cellulose• Maize‐Mono• Beet‐Mono• Maize/Beet

(80/20; 20/80)• Wheat‐Mono• Wheat/Beet

(80/20; 20/80)• (Gras‐Mono)• (Grass /x)

Project Flow Chart

freshfor HBT

before ensilingfor Batch

before ensilingfor CFT

ensiling (90d)for Batch/ CFT

fermentationin Batch (28d)

Batch test

HBT –Hohenheim fermentation test

CFT –Continuous fermentation test

fermentationin CFT (90d)

fermentationin HBT (28d)





fermentation residuesfrom HBT

fermentation residuesfrom Batch

fermentation residues from CFT

& soilhomogenised

& soilsmall lyis‐meter

& soilopen field

ILV• DM, oDM pH• Weender analysis• organ. acids

IPÖ• CO2‐ gas exchange • micro calorimetrie• number/biomass• org./anorg. substances

IBK• shear test:Rheometer

ILV• DM, oDM, pH• fermentation quality• organ. acids• alcohols

ILV• kinetics• spez. gas yield:

• biogas• methane

ILV• pH, FOS/TAC• organ. acids

IBK• Rheology

IBK• sorptivity, pH, • electric conductivity• dispersible clay

IPÖ• CO2‐ gas exchange • micro calorimetry• number/biomass• org./anorg. Substances



• shear test:shearing offdevice



• water content• soil‐moisture tension• infiltration

survey& analysis:

Project Flow Chartsubstrates:• Inoculum• Cellulose• Corn‐Mono• Beet‐Mono• Corn/Beet


(80/20; 20/80)• (Gras‐Mono)• (Grass /x)

freshfor HBT










& soilhomogenised


& soilopen field

ILV• DM, oDM pH• Weender analysis• organ. acids

ILV• DM, oDM, pH• fermentation quality• organ. acids• alcohols

ILV• kinetics• spez. gas yield:

• biogas• methane

ILV• pH, FOS/TAC• organ. acids

survey& analysis:

substrates:• Inoculum• Cellulose• Corn‐Mono• Beet‐Mono• Corn/Beet


(80/20; 20/80)• (Gras‐Mono)• (Grass /x)

freshfor HBT



Substrate/Ensiling/Fermentation:• new substrates / mixture of substrates• ensiling losses• efficiency & kinetics of fermentation [S. Ohl, E. Hartung]

M&M and first Results – ensiling / fermentation

• 15 fermenters• mesophilice conditions • every 14 days increase the loading rate• every day 2x gas analysis• every 14 days investigation of digestates• after 8 months test will be finished• Digestates/residues for microbiological

and soil researches

Continuous fermentation test

• ensiling in barrel, preserving jar or plastic bag

• Air tight• Storage for 90 days• 5 replications• Estimation dry matter losses• Silage quality

Silage trial

M&M and first Results – ensiling / fermentation

fresh dried and milled substrates – HBT‐tests

up to now, no co‐fermentation effects could be observed

M&M and first Results – HBT / Kinetics

050

100150200250300350400

0 5 10 15 20 25 30spec. M

etha

neProd

uctio

n[lN

/kgoDM]

Time[d]

100% Wheat

050

100150200250300350400

0 5 10 15 20 25 30

spec. M

etha

neProd

uctio

n[lN

/kgoDM]

Time [d]

100% Maize

0

50

100

150

200

250

300

350

400

0 5 10 15 20 25 30

spec. M

etha

neProd

uctio

n[lN

/kgoDM]

Time [d]

80% Maize + 20% Sugar Beet

0

50

100

150

200

250

300

350

400

0 5 10 15 20 25 30

spec. M

etha

neProd

uctio

n[lN

/kgoDM]

Time [d]

20% Maize + 80% Sugar Beet

324 lN/kgoTS 353 lN/kgoTS

345 lN/kgoTS 318 lN/kgoTS

M&M and first Results – HBT / Kinetics








& soilhomogenised


& soilopen field

IPÖ• CO2‐ gas exchange • micro calorimetrie• number/biomass• org./anorg. substances



survey& analysis:



(80/20; 20/80)• (Gras‐Mono)• (Grass /x)

freshfor HBT



Soil‐Microorganisms /‐nutrients/Microorganism activity:• “substrate enrichment” by fermentation• influence on microorganism activity/community• “fertiliser” threshold definition[A. Hold, M. Bölter, (E. Hartung)]

M&M and first Results – soil microorganisms

[A. Hold, M. Bölter]


• 2 types of soil• 4 types of mono‐fermented “residues” (maize, grass, sugar beet, wheat)• 6 types of co‐fermented “residues”

Each soil type is mixed with every “residue” in 4 quantities: (0µl/cm2; 125µl/cm2; 250µl/cm2; 500µl/cm2)

• Storage of all “mixtures”/samples for 32 days by 10° C• all samples are analysed on day 0, 4, 8, 16 and 32• Microbial activity is detected by: micro calorimetry, Co2‐Gas exchange, biochemical

oxygen demand (BOD), microscopy

[A. Hold, M. Bölter]


• Highest nitrate contents appeared on day 32 in all samples with the maximum quantity of applied “residue”

• quantity of nitrate increases during the process an with increasing quantities of applied “residue”

• in all samples dissolved carbohydrates were reduced during the process (lowest on day 32)

• Highest bacterial number and activity was detected in the samples with 125µl/cm2








& soilhomogenised


& soilopen field


IBK• Rheology

IBK• sorptivity, pH, • electric conductivity• dispersible clay





• water content• soil‐moisture tension• infiltration

survey& analysis:



(80/20; 20/80)• (Gras‐Mono)• (Grass /x)

freshfor HBT



Soil‐Properties/‐Structure/‐Characterisation:• decrease of pH (sludge) & acidification• alternation of soil sorption / surface properties • destabilisation & reduction of soil structure[A. Voelkner, D. Holthusen, R. Horn]

M&M and first Results – impact on soil

M&M and first Results – soil sample preparation [A. Voelkner, D. Holthusen, R. Horn]

homogenised

grading (< 2mm)

(pre) dehydration(‐60 hPa, 7 d)

application fer‐mentation residue

dehydration14 d

removing of applied fermen‐tation residue

soil layer separation influence of soil depth

1

23

4

56

M&M and first Results – soil surface properties[A. Voelkner, D. Holthusen, R. Horn]

Hydrophobic > 90° vs. Hydrophilic < 90°

Ellerbrock et al. (2005) Graber et al. (2005)

M&M and first Results – soil (surface) properties[A. Voelkner, D. Holthusen, R. Horn]

Contact angle ‐> Hydrophilic < 90° vs. Hydrophobic > 90°

Change of contact angle [°] at

different depths (1‐6 cm) in

clayey soil with respect to

different types of fermentation

residues

n = 10

90°

90°

90°

Maize MonoMaize Mono Wheat Mono Reference 1

Maize/Beet 80/20 Beet/Maize 80/20 Reference 2

M&M and first Results – soil (surface) properties[A. Voelkner, D. Holthusen, R. Horn]

Contact angle ‐> Hydrophilic < 90° vs. Hydrophobic > 90°

Change of contact angle [°] at

different depths (1‐6 cm) in sandy

soil with respect to different

types of fermentation residues

Change to smaller amounts of

applied residues (in more relation

to on‐farm application amounts)

Maize 100 %Beet 100%Beet 80% Maize 20%Maize 80% Beet 20%Wheat 80% Beet 20%Reference

Contact A

ngle [°]

Depth [cm]

Maize 100 %Beet 100%Beet 80% Maize 20%Maize 80% Beet 20%Wheat 80% Beet 20% Reference

Beet 100%

Beet 80% Maize 20%

Maize 100%

Conclusions

• joint project still within the first year• interdisciplinary approach • focus along process‐/production chain• comments & advice especially with respect to project approach

are welcome• starting point for additional international projects

• CH4‐yields fit to literature• no co‐fermentation effects up to now• differences in fermentation kinetics & efficiency• dissolved carbohydrate decrease in all samples after “mixture”• number & activity of bacterial “depended” on “mixture”‐rate• no short term acidification process due to residue application• residues introduce change to hydrophobic soil surface properties• differences between residues with respect to their change to

“hydrophobic properties”

Documents

September 5th, Höör, Sweden - SGC · • M&M and first Results ... 100 150 200 250 300 350 400 0 5 10 15 20 25 30 spec. spec. ... • Storage of all “mixtures”/samples for 32