Transcript Document

DAYCENT Model Overview,
Testing and Application to
Agroecosystems
S.J. DEL GROSSO, W.J. PARTON, D.S.
OJIMA, A.R. MOSIER and C. KEOUGH
DAYCENT MODEL
S=soil type
V=veg type
L=land use
CH4
Uptake
N GAS
0-1 cm
1-4 cm
4-15 cm
15-30 cm
etc.
S,Rh
V
NPP
H2Osoil
Tsoil
CO2
PLANT
COMPONENTS
LEAVES
NO3-
0-1 cm
1-4 cm
4-15 cm
15-30 cm
etc.
NH4+
0-1 cm
1-4 cm 0-15 cm
4-15 cm
15-30 cm
etc.
FINE ROOTS
PPT,V,L
S
C:N
BRANCHES
LARGE WOOD
SOM
LARGE
ROOTS
DEAD PLANT Decomp
MATERIAL
Rh S
STRUCTURAL
C:N
METABOLIC
CO2
C:N
Rh
ACTIVE
0.5-1 yr
SLOW
10-50 yr
PASSIVE
1000-5000 yr
Parton et al. 1998
Kelly et al. 2000
Del Grosso et al. 2001
S
S
CO2
Improved NPP Submodel
Potential Growth
(CO2,T,H2O)
Nutrients
Shading
Crop
H2O
GRAIN
C,N,P,S
SHOOT
C,N,P,S
Tillage
Temp
H2O
NPP
Phenology
Nutrient/H2O stress
SURFACE
LITTER
ROOT
C,N,P,S
Temp
H2O
SOIL
LITTER
PG = Gpot*F(light)*F(LAI)*F(Temp)*F(H2O)
Del Grosso et al. in prep.
WATER FLOW SUBMODEL
ATMOS
PRECIP
ATMOS
Tair
Evap
PET
ROOT
PET
PET
SNOW
BIOMASS
INTERCEPTION
PET
Sublimation
Tair
Melting
Infiltration
KSAT
KSAT
H2O 0-1 cm
KSAT
hpot
H2O 1-4 cm
KSAT
OUTFLOW
hpot
H2O 4-15 cm
KSAT
hpot
H2O 15-30 cm
KSAT
hpot
KSAT
H2O 145-160 cm
Parton et al. 2001
Parton et al. 2001
coarse
fine
Del Grosso et al. 2000
Recent Model Improvements
•Variable effective plant rooting depth
•PET = F(Lat, DOY, Tavg, Tmax – Tmin)
•Weekly scheduling of management events
•Germination = F(Tsurface)
•Harvest/Senescence = F(GDD, Tsurface)
•Canopy absorption of NOx emitted from soil
400
KBS corn/soy/wheat conv till
350
gC m-2 yr-1
300
grain sim
grain obs
250
200
150
100
50
0
1989
1991
1993
16
1995
1997
1999
N grain sim
14
N grain obs
-1
8
gN m yr
10
-2
12
6
4
2
0
1989
1991
1993
1995
1997
1999
KBS DF
15
sim
obs
-1
N2O gN ha d
-1
20
10
5
0
50
KBS Plow High Fert
-1
N2O gN ha d
-1
40
30
sim
obs
20
10
0
1/1/96
7/1/96
12/30/96
6/30/97
12/29/97
350
Corn - CT Irr Fert
300
gN ha-1 d-1
250
N2O sim
N2O obs
200
150
100
50
0
03/15/02 04/14/02 05/14/02 06/13/02 07/13/02 08/12/02 09/11/02
120
Corn - NT Irr Fert
gN ha-1 d-1
100
N2O sim
80
N2O obs
60
40
20
0
03/15/02 04/14/02 05/14/02 06/13/02 07/13/02 08/12/02 09/11/02
N2O gN/ha/d
1500
Soy-Fallow Fert
1000
obs N2O
sim N2O
500
0
0
25
50
days after fert
75
100
IPCC Emission Factor Calculations
Direct N2O emissions
Ncult = 0.1 gN m-2 yr-1
Nom = Nsludge + Nmanure
N2Odirect = 1.25%*(Nstuble + Nfert + Nom) + Ncult
Indirect N2O emissions
NH3 + NOx = 0.1Nfert
Nleach = 0.3Nfert
N2Oindirect = 0.01(NH3 + NOx) + 0.025Nleach
mean N2O
1
gN m-2 yr-1
observed
0.8
DAYCENT
0.6
Emission Factor
0.4
0.2
w
llo
so
y/
fa
co
rn
TN
co
rn
CO
CO
IA
25
mean N leached
20
gN m-2 yr-1
ba
rle
y
he
at
CO
w
co
rn
O
tta
wa
wh
ea
t
NE
KB
S
KB
S
al
fa
ro
ta
t io
n
lfa
0
obs
15
DC
10
EF
5
n
po
ta
to
no
co
rn
hi
g
rn
co
co
r
N
N
h
N
gh
hi
ea
n
oy
b
n/
s
co
r
oy
b
co
co
rn
/s
rn
/s
oy
b
ea
n
ea
n
m
lo
ed
w
N
N
0
500
mean grain/hay yields
gC m-2 yr-1
400
obs
300
DC
200
100
0
KBS alfalfa
KBS
rotation
NE wheat
Ottawa
corn
corn/soy
corn
corn/potato
a)
2
modeled N2O gN m-2 yr-1
1.5
y = 0.76x + 0.05
R2 = 0.72
EF
DAYCENT
1
Linear (EF)
Linear (DAYCENT)
y = 0.34x + 0.26
R2 = 0.63
0.5
0
0
0.5
1
1.5
-2
2
-1
observed N2O gN m yr
modeled NO3 leached gN m -2 yr-1
b)
25
y = 0.97x - 0.13
20
R2 = 0.96
EF
15
DAYCENT
Linear (EF)
Linear (DAYCENT)
10
y = 0.47x + 0.95
2
R = 0.74
5
0
0
5
10
15
20
-2
-1
observed NO3 leached gN m yr
Fig4
25
National GHG Inventory
•Bruce McCarl’s 63 regions
•EPIC soils and daily climate data
•Simulated dominant rotations for each region
•Rain fed and irrigated
•N fertilizer but no manure additions
•Converted model output in gN2O-N m-2 to regional
totals for the dominant crop rotations using state
level planted acres reported by NASS
25
Major Crop Areas
corn
20
millin ha
soy
hay
15
wheat
cotton
10
5
0
CEN
NE
NW
SE
SW
Regional Level Validations
State Level Grain/Hay Yield Validations
600
sim gC m -2 yr -1
500
400
300
200
R2 = 0.65
100
0
0
100
100
200
300
400
obs gC m-2 yr-1
500
600
Grain and Hay Yields
90
80
yield obs
annual Tg C
70
yield sim
60
50
40
30
20
10
0
CEN
NE
NW
SE
SW
Simulated Regional N2O Emissions
25
Direct N2O
annual Tg C
20
15
EF
DC
10
5
0
CEN
NE
9
NW
SE
SW
Indirect N2O
8
annual Tg C
7
6
EF
5
DC
4
3
2
1
0
CEN
NE
30
NW
SE
SW
Total N2O
annual Tg C
25
20
EF
15
DC
10
5
0
CEN
NE
NW
SE
SW
N2O by Crop
16
Direct N2O
14
12
annual Tg C
EF
10
DC
8
6
4
2
0
corn
5
cotton
alfalfa
soy
wheat
Indirect N2O
4
annual Tg C
EF
3
DC
2
1
0
corn
18
cotton
alfalfa
soy
wheat
Total N2O
annual Tg C
15
EF
12
DC
9
6
3
0
corn
cotton
alfalfa
soy
wheat
National N2O and GHGnet
60
N2 O
annual Tg CO2-C
50
40
EF
30
DC
20
10
0
direct
Indirect
20
total
GHGnet
CO2
CH4
annual Tg CO2-C
15
N2O
Nfert
GHGnet
10
5
0
CEN
NE
NW
SE
SW
Nfert
GHGnet
-5
GHGnet
40
35
annual Tg CO2-C
30
25
20
15
10
5
0
-5
-10
CO2
CH4
N2O
Area normalized N2O
25
N2O Direct
annual gC m
-2
20
15
10
5
0
annual gC m
-2
CEN
NE
NW
20
N2O indirect
18
16
14
12
recent modern cropping
SE
SW
SE
SW
SE
SW
pre 1940 management
native vegetation
10
8
6
4
2
0
CEN
NE
40
NW
N2O total
35
annual gC m-2
30
25
20
15
10
5
0
CEN
NE
NW
Area normalized GHGnet
GHGnet
40
annual gC m-2
30
20
recent modern cropping
pre 1940 management
native vegetation
10
0
-10
-20
CO2
CH4
N2O
Nfert
GHGnet
EPA vs. DAYCENT N Inputs
12
N inputs
Tg N yr
-1
10
8
EPA
6
DC
4
2
0
N fert
manure
sludge
N fix
resudue N
5000
Major Crop Areas
wheat
hay
4000
corn
soy
cotton
ha
3000
2000
1000
0
CO
KS
40
MT
ND
NE
NM
OK
SD
TX
WY
Mean GHG fluxes per unit area
-1
10
g CO2-C m yr
20
-2
30
BAU
IM
0
-10
-20
-30
-40
10000
del C soil
N2O dir
N2O ind
Mean GHG fluxes
CH4
Cnet
ton CO2-C yr
-1
5000
0
-5000
BAU
IM
-10000
-15000
-20000
del C soil
N2O dir
N2O ind
CH4
Cnet
gCO2-C m-2 yr-1
Mean GHG fluxes per unit area
30
25
20
15
10
5
0
-5
-10
-15
-20
-25
wheat/fallow
wheat/corn/fallow
del C soil
N2O dir
N2O ind
CH4
Cnet
Mean GHG fluxes per unit area
60
40
gCO2-C m-2 yr-1
20
0
-20
wheat continuous
-40
corn/soy/wheat
-60
-80
-100
del C soil
N2O dir
N2O ind
CH4
Cnet
Mean GHG fluxes per unit area
80
-2
gCO2-C m yr
-1
60
40
20
0
irr corn ct
-20
irr corn nt
-40
-60
del C soil
N2O dir
N2O ind
CH4
Cnet