ucc opportunities for carbon sequestration in irish grasslands vesna jakši ć supervisors: g....
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UCCUCC
Opportunities for Carbon Sequestration in Irish
Grasslands
Vesna Jakšić
Supervisors: G. Kiely, University College Cork
O. Carton, D.Fay, Johnstown Castle
Dublin, 20/11/2003
UCCUCC
Why study atmosphere Carbon Dioxide ?
The Kyoto Protocol for Ireland requires that emissions of GHG must be no more than 13% above the 1990 levels
As of 2001, emissions are 31% greater than the 1990 levels (EPA)
By 2008 – 2012 the “business as usual” scenario forecast (produced in 2000 based on 1998 data) is that emissions may be more than 37% greater than the 1990 levels (NCCS)
Agricultural is responsible for about 27% (soils 5.5%) in 2001 of emission (EPA)
Opportunities for Carbon Sequestration in Irish Grasslands
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Question ?
Opportunities for Carbon Sequestration in Irish Grasslands
Are agricultural soils sources or sinks for carbon ?
Air
Soil
Source Sink
C sequestrationC sequestration
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Budget of Carbon for a farm
NEE – (A + B + C+…) = Csoil
NEE = Net Ecosystem exchange in T of C/ha
NEE = GPP – Rh – Ra
A, B, C… = carbon leaving the farm
(in milk, in meat, in enteric fermentation etc.)
CCsoil soil = the carbon fixed to the soil = the carbon fixed to the soil
or lost to the atmosphere?or lost to the atmosphere?
Opportunities for Carbon Sequestration in Irish Grasslands
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Objectives of project
Measure and model the CO2 flux at grasslands in
Dripsey (Cork) and Johnstown Castle (Wexford)
Investigate seasonal, annual and interannual
fluxes
Estimate the carbon budget at farm scale and so
determine if the soils are sinks or sources of
carbon
Opportunities for Carbon Sequestration in Irish Grasslands
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Sites
Wind Rose Downwind direction is SW
Cork grassland – Dripsey
Elevation ~ 190masl
Annual rainfall ~ 1450mm
Opportunities for Carbon Sequestration in Irish Grasslands
red dots ↔ site areas
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NEE – Eddy Covariance System
Opportunities for Carbon Sequestration in Irish Grasslands
Rain gauge
Temperature and relative humidity probes at 3m
Perimeter for soil moisture, soil temperature and soil heat flux probes
The automatic weather station– tower in full height
Sonic anemometerNetradiometer
LICOR H2O/CO2
sensor
LICOR electronics box
Top of the tower with instruments
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Eddy Covariance
Opportunities for Carbon Sequestration in Irish Grasslands
Hz(m/sec)@10
Hz10@(mol/m 2
speed windvertical of nfluctuatio the
CO of nfluctuatiodensity the
time averaging minute 30
offlux the
)3
w'
ρ'
ρ'w'- F
CO F
c
c c
2 c
Sonic anemometer
LI-7500 Open Path CO2/H2O gas analyser
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Footprint area
Opportunities for Carbon Sequestration in Irish Grasslands
Estimated footprint
N
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CO2 flux measurements
July 2001 to Jun 2003 (the results for 24 months)
Nitrogen in chemical fertilizer was applied at the
rate of 190kgN/ha and N in slurry approximately
90kgN/ha for the year 2002
The site is intensive cattle grassland (Livestock
density 2.2 LU/ha) with mix of grazing and silage
Opportunities for Carbon Sequestration in Irish Grasslands
UCCUCC
-40
-30
-20
-10
0
10
20
Flu
x o
f C
O2
[ m
ol/m
2 .sec
]
Measured
19/08 20/08 21/08
August 2002
Net Photosynthesis
Net Respiration
Raw CO2 flux data @ 30 minute intervals
Opportunities for Carbon Sequestration in Irish Grasslands
UCCUCC
CO2 flux and soil moisture
Opportunities for Carbon Sequestration in Irish Grasslands
SIN
K
S
OU
RC
E
Soil porosity48%
jul aug sep oct nov dec jan feb mar apr may jun jul aug sep oct nov dec jan feb mar apr may jun-400
-300
-200
-100
0
100
200
[g/m
2 ]
jul aug sep oct nov dec jan feb mar apr may jun jul aug sep oct nov dec jan feb mar apr may jun0.2
0.25
0.3
0.35
0.4
0.45
0.5
[m3 /m
3 ]
CO2 flux per month
soil moisture at root zone
2001 2002 2003
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jul augsepoct novdec jan febmar aprmayjun jul augsepoct novdec jan febmar aprmayjun-6
-5.5
-5
-4.5
-4
-3.5
-3
-2.5
-2
-1.5
-1
-0.5
0
0.5
[T o
f C
/ha]
-22
-20
-18
-16
-14
-12
-10
-8
-6
-4
-2
0
[T o
f C
O 2 /h
a]
2001 2002 2003
-3.7
1 2
-2.2
(13.6)
(8.1)
Cumulative uptake T Carbon/ha
Opportunities for Carbon Sequestration in Irish Grasslands
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Cumulative uptake T Carbon/ha
jan feb mar apr may jun jul aug sep oct nov dec-4
-3.5
-3
-2.5
-2
-1.5
-1
-0.5
0
0.5
[T o
f C
/ha]
-14
-12
-10
-8
-6
-4
-2
0
[T o
f C
O2/h
a]
9.2
Year 2002
Opportunities for Carbon Sequestration in Irish Grasslands
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Some NEE values
location Type of landNEE
[T of C/ha.yr]
1 Duke, US Loblolly pine forest 5.7 to 7.9
2 Mandan, US Native prairie 0.6 to 0.9
3 Woodward, US Plain prairie -0.2 to 1.8
4 Temple, US Mixed-grass prairie 2.2 to 7.7
5 Ottawa, Canada Bog peatland 0.5 to 0.9
6 Cork, Ireland Perennial ryegrass pasture 2.2 to 3.7
Opportunities for Carbon Sequestration in Irish Grasslands
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Carbon leaving the farm
Opportunities for Carbon Sequestration in Irish Grasslands
A. Carbon in milk [t.C/ha.yr.] average production 7500L/ha. density φ = 1.03kg/L carbon in milk = 4.5%
310100
5.403.17500 C
CA = 0.35 T.C/ha.
B. Carbon in meat [t.C/ha.yr.] ~18% of live weight 1LU = 520kg pasture dry matter per year Stocking Density for Dripsey = 2.2LU/ha Assume that 1/3 of animals leave farm for
the meat factory
CB ≈ 0.1 T.C/ha
31031
10018
5202.2 C
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Carbon leaving the farm
Opportunities for Carbon Sequestration in Irish Grasslands
C. Carbon in CH4 respired from animal and CH4 from manure for full year
100kg CH4 from animal 15kg CH4 from manure Stocking Density for Dripsey = 2.2LU/ha CC = 0.20T.C/ha.
D. Carbon as CO2 from respiring animal indoors for 4 months of year
Diet = 10kgDM/day/LU DM = 45%Carbon Assume 40% respire CD = 0.45 T.C/ha
3101612
2.2151 C
31010040
124
2.210045
36510 C
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Carbon BudgetCO2
Net Ecosystem ExchangeNEE
-2.5 T.C/ha/yr
AtmosphereAtmosphere
CanopyCanopy C as DOC/DIC in stream+0.1 T.C/ha/yr
C as CH4 from yard manure / slurry +0.1 T.C/ha/yr
C as CO2 from respiring animal indoors for 4 months of year
+0.45 T.C/ha/yrC in milk export+0.35 T.C/ha/yr
C in meat export+0.1 T.C/ha/yr
C as CH4 from animal +0.2 T.C/ha/yr
SoilSoilSoil Sequestration
-1.2 T.C/ha/yr
Opportunities for Carbon Sequestration in Irish Grasslands
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Conclusions
Opportunities for Carbon Sequestration in Irish Grasslands
For 8 months (Mar to Oct) the site is a sink of carbon
Interannual variability of NEE is significant
(2.2 to 3.7 T of C/ha.yr) – need long term measurements
Preliminary results – carbon sequestration for 2002
at Cork site is 1.21.2 T of C/ha.yr (forestry 3 to 6 T of C/ha)
Preliminary results suggest that there may be
opportunities for Carbon sequestration in grassland soils