Emission of greenhouse gases from manure

Sven G. Sommer

Dept. of Agricultural Engineering

Danish Institute of Agricultural Sciences

Change in temperature

GHG emission inventories

Greenhouse gas emission, mill. ton CO2

0 10 20 30 40 50 60 70 80

Denmark

Agriculture

Manure+ruminants

Ruminants

Manure

Livestock manure is a source of greenhouse gases

• Nitrous oxide (N2O) produced during nitrification and denitrification of nitrogen in manure

• Methane (CH4) produced during anaerobic break down of organic matter in manure

Global warming potential of N2O and CH4

• N2O:310 times higher climate warming potential than that of carbon dioxide

• CH4: 21 times higher potential than that of carbon dioxide

Methane production

Biomasse:Animal manureOrganic waste

Hydrolysis

Dissolved substrate

Acidogenesis

H2+CO2

Acetognesis

VFA>C2

CH4+H2O+ CO2

CH3-COOH

Methanogenesis

Hydrolysis is process rate controlling

VFA transformation reduced due to:

High NH3

Sudden changes in environment

Feedback:

High VFA conc. reduces hydrolysis

Transformation of N in animal manure

nitrogen Manure

Interface

Atmosphere

)(

)()(

)(

)(

)()(

)()()(

23

2

22

2

2

4,3

,34

,3

NNO

ON

NON

EmissionEmission

ON

ON

Emission

NOrg

NHNHTAN

HNHNH

NH

Emission

L

G

L

G

L

L

G

Methane emissionManure housing

kg CO2-C eqv. LU-1Y-1

0 1500 3000 4500 6000

Manure stores outside

kg CO2-C eqv. LU-1Y-1

0 1500 3000 4500 6000

Beef deep litter

Fatteners slurry

Pigs straw flow

Cattle slurry

Cattle solid manure

Pig slurry

Pig solid manure

Slurry - methaneSommer et al. 2005;P. Kai, P.J. Dahl & H.D. Poulsen, 2005.

Stored frozen

Days from start of slurry addition

0 10 20 30 40

Met

hane

em

issi

on, g

C h

-1kg

-1[V

S]

0.000

0.005

0.010

0.015

0.020

0.025

0.030 Without inoculum10% inoculum

Fresh manure

Days from start of slurry addition

0 5 10 15 20M

etha

ne e

mis

sion

, g C

h-1

kg-1

[VS]

0.000

0.005

0.010

0.015

0.020

0.025

0.030(0.08)

Nitrous oxide

Manure housing

kg CO2-C eqv. LU-1Y-1

0 2000 4000 6000

Manure stores outside

kg CO2-C eqv. LU-1Y-1

0 100 200 300

Pig slurry

Dairy cow solid manure

Pigs deep litter

Cattle slurry

Cattle deep litter

Pig deep litter

Housing

Deep litter cattle - little N2O emission (Henriksen et al. 2000)

Temperature, oC

0 10 20 30 40 50

Dep

th, c

m

-100

-80

-60

-40

-20

0

Oxygen, vol%

0 5 10 15 20 25

TemperatureOxygen

Ammonium, g N kg(DM)-1

0 1 2 3 4 5 6 7 8 9

Dyb

de, c

m

-100

-80

-60

-40

-20

0

Nitrate, g N kg(DM)-1

0,019 0,020 0,021 0,022

Nitrate Ammonium

Temperature gradients in manure heaps

• High temperatures near heap surface

• Low temperatures in the centre of the heap

Anaerobic part: CH4

Intermediate zone

Aerobic zone: N2O

Covering a heap of manure, oxygen

Uncovered Covered

Centre

Ambient

10 cm below surface

Solid manure store – methane (Hansen MN et al. 2005)

Uncovered

Covered

Un-covered heap Covered heap

10 cm below surface

Centre

Solid manure store – nitrous oxide(Hansen MN et al. 2005)

b

0

200

400

600

800

1000

0 30 60 90 120

Days after start of storage

Con

c. o

f N2O

, pp

m

a

0

200

400

600

800

1000

0 30 60 90 120Days after start of storage

Con

c. o

f N2O

, pp

m

0

200

400

600

800

1000

0 30 60 90 120

Uncovered

Covered

10 cm below surface

Centre

Un-covered heap Covered heap

Stored slurry nitrous oxide

Nitrous oxide

N2O

em

issi

on, 1

0-3

g N

m-2

h-1

0

5

10

15

20

25

30

No coverSurface crustLeca pebblesStraw cover

Temperature

Day of the year

180 200 220 240 260

Slur

ry te

mpe

ratu

re, o C

10

15

20

25

LECA

Straw

Surface crust

Conclusion

• Inhouse manure stores:

– Methane production,

– No nitrous oxide emission (except from pig deep litter ?)

• Outside stores:

– Methane from slurry and solid manure,

– Nitrous oxide from solid manure and traces from crust on slurry