Post on 24-Apr-2022
AquaCropA new model for crop predictionunder water deficit conditions
- Calibration for potato -
Gabriella IZZIgabriella.izzi@fao.org
Centro Internacional de la Papa (CIP)La Molina, Lima, Peru22 September, 2008
Objectives
• General framework
• Main issues related to AquaCropcalibration for potato
• AquaCrop performances
• Description of AquaCrop
• Discussion, feed-backs, & contacts
Background• Revision of the 1979 FAO I &
D Paper no.33,
“Yield Response to Water”
• Consultative process
• Separation herbaceous-crops and trees:AquaCrop &
Guidelines
Ya ETa
1 - = Ky 1 -
Ym ETc
Why another model?U
ncer
tain
tyU
ncer
tain
ty
ComplexityComplexity
structure
parameters
total
• AquaCrop is explicit and mostly intuitive, and maintains anoptimum balance between simplicity, accuracy and robustness
• AquaCrop differs from other models for its relatively small number of parameters
• AquaCrop is aimed at practical end-users: farmers and irrigation associations, extension services, governmental agencies, NGOs, planners, economists, as well as researchers and students.
AquaCrop main characteristics
• AquaCrop as unique crop response to water modelwith crop-specific parameters
Evolution from Paper 33
CanopyCanopyTranspirationTranspiration
BIOMASSBIOMASS
CropCropEvapotEvapotranspirationranspirationYIELDYIELD
EHI
Paper 33
{AquaCrop
long-term sums
daily time-steps
Ky
WP
Water-driven model
Atmosphere
Soil
AquaCrop Conceptual Framework
Crop
Man
agem
ent
Rain
AquaCrop Conceptual Framework | Atmosphere
CLIMATE
RS , T, RH, u
ETo
T (oC) CO2
Data needed for calibration | Atmosphere
Rainfall ETo Tmin & Tmax
Phenology Canopy CoverLeaf expansion gs
Senescence
Rooting depth
AquaCrop Conceptual Framework | Crop
CGC
CCx
start of canopy senescence
time to harvest
cano
py c
over
timetime to full canopy
CDC
CCo
Canopy Cover (CC) follows the exponential growth during the first halfof the full development (Eq. 1) and an exponential decay during the second half of the full development (Eq. 2)
tC GCoeCCCC ⋅= (1)
tCGCoxx e)CCCC(CCCC ⋅−⋅−−= (2)
AquaCrop Conceptual Framework | Crop
Data needed for calibration | Crop
PhenologyIn-season CCDensity
Es Ta
Phenology Canopy CoverLeaf expansion gs
SenescenceBiomass
WP
Rooting depth
AquaCrop Conceptual Framework | Crop
T (oC) ETo
(g m-2 mm-1)∑
=CT
BiomassWP(g m-2)
)2000(COO
C
*
2ETT
BiomassWP
⎥⎥⎥⎥⎥
⎦
⎤
⎢⎢⎢⎢⎢
⎣
⎡
⎟⎟⎠
⎞⎜⎜⎝
⎛=
∑
Σ ETc (mm x 1000)0.0 0.3 0.6 0.9
Bio
mas
s (k
g m
-2)
0
1
2
3
SorghumSunflowerChickpeaWheat
∑ CT Σ(ETc/ETo)0 40 80 120 160
Bio
mas
s (k
g m
-2)
0
1
2
3
SorghumSunflowerChickpeaWheat
∑ )ET/T( OC
AquaCrop Conceptual Framework | Crop
Data needed for calibration | Crop
In-season dry biomass
Es Ta
Phenology Canopy CoverLeaf expansion gs
SenescenceBiomass
WP
YieldHI
Rooting depth
AquaCrop Conceptual Framework | Crop
T (oC) ETo
Data needed for calibration | Crop
In-season yield
AquaCrop conceptual framework | Crop
Water stress coefficients
AquaCrop conceptual framework | Crop
Water stress coefficients
Data needed for calibration | Crop
Different water regimes
Soil water (&
salt) balanceInfiltration
Redistribution
Runoff
Rain
Ks
Es Ta
AquaCrop Conceptual Framework | Soil
deeppercolation
Texture 1
Texture 2
Texture …
Ksat
FC
PWP
Irrig.
Runoff
Data needed for calibration | Soil
FC, PWP, KsatSoil layers
Field Management
Water Management
• Fertility level (non-limiting; high; moderate; poor)
• Field-surface practices (mulching; soil bunds)
Rainfed
• User defined schedule (timing and depth)
• Model-generated schedule (fixed interval; fixed depth;% of RAW)
• Irrigation method (drip; sprinkler;surface » basin; border; furrow)
Irrigation
AquaCrop Conceptual Framework | Management
Data needed for calibration | Management
Irrigation depthIrrigation date
Data needed for calibration | Management
Fertility level
AquaCrop performances
Maize
TexasTexas
CaliforniaCaliforniaFloridaFlorida
SpainSpain QuzhouQuzhou
I treatment biomass
0
500
1000
1500
2000
2500
3000
0 20 40 60 80 100 120 140
DAP
cum
DM
(g/m
2)
DM
Biomass
I (Full IRR) treatment Ground Cover
0
20
40
60
80
100
0 20 40 60 80 100 120 140
DAP
GC
(%)
Calc GC
CC
Maize
Treatments:Full Irrigation (I)Rainfed (NI)Irrig. day 55 onward (I55)
NI treatment biomass
0
500
1000
1500
2000
2500
3000
0 20 40 60 80 100 120 140
DAP
cum
DM
(g/m
2)
DM
Biomass
California
NI (No IRR) treatment Ground Cover
0102030405060708090
100
0 20 40 60 80 100 120 140
DAP
GC
(%)
Calc GC
CC
I55 (IRR on Day55) treatment Ground Cover
0
20
40
60
80
100
0 20 40 60 80 100 120 140
DAP
GC
(%)
Calc GC
CC
I55 treatment biomass
0
500
1000
1500
2000
2500
3000
0 20 40 60 80 100 120 140
DAP
cum
DM
(g/m
2)
DM
Biomass
Biomass YieldMeasured Simulated Measured Simulated
24.3 22.7 11.4 10.816.8 16.8 5.2 6.221.2 22.4 10.3 10.6
Cotton
SpainSpainTexasTexas GreeceGreece
TurkeyTurkey
SyriaSyria
Cotton
0
2
4
6
8
10
12
14
0 2 4 6 8 10 12 14
Observed (t ha-1)
Sim
ulat
ed (t
ha
-1)
Yield
Biomass
1:1
Treatments:Full IrrigationDeficit Irrigation
Spain
Cotton
Treatments:Full IrrigationDeficit Irrigation
Syria
Wheat
TexasTexas
KansasKansas
SardiniaSardinia
QuzhouQuzhou
LuanchengLuancheng
FengquiFengqui
Wheat
Treatments:98-99 – Full Irr.99-00 – Full Irr.
ChinaYield
Measured Simulated
6.72 6.506.22 7.09
China Quzhou Wheat 98-99
0
5
10
15
20
25
30
35
40
0 50 100 150 200 250DAP
Bio
mas
s (t
/ha)
China Quzhou Wheat 98-99
-20
-10
0
10
20
30
40
0 50 100 150 200
DAP
Min
and
Max
Tem
pera
ture
(oC
)
China Quzhou Wheat 98-990
25
50
75
100
0 50 100 150 200 250DAP
Can
opy
Cov
er (%
)
0
25
50
75
100
0 50 100 150 200 250DAP
Can
opy
Cov
er (%
)
China Quzhou Wheat 99-000
5
10
15
20
25
30
35
40
0 50 100 150 200 250DAP
Bio
mas
s (t
/ha)
China Quzhou Wheat 99-00
China Quzhou Wheat 99-00
-20
-10
0
10
20
30
40
1 31 61 91 121 151 181 211
DAP
Min
and
Max
Tem
pera
ture
(oC
)
Quinoa
BoliviaBolivia
Quinoa
Treatments:Full IrrigationDeficit Irrigation
Bolivia
Conclusions
• AquaCrop calibration and validation need solid datasets, under a variety of agro-climatic, water and fertilization conditions
• AquaCrop needs to be calibrated for potato
• AquaCrop shows first encouraging results, under full, deficit and rainfed conditions
Thank You