inleiding na “aquacrop”
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Food and Agriculture Organization Land and Water Division. Training modules. Inleiding na “AquaCrop”. February 2010 prepared by Dirk Raes. Simulasie as “tool” om riglynne te maak. - PowerPoint PPT PresentationTRANSCRIPT
1.Inleiding na “AquaCrop”
Training modules
Food and Agriculture OrganizationLand and Water Division
February 2010 prepared by Dirk Raes
Simulasie is deur ‘n wiskunde model gedoen
Simulasie as “tool” om riglynne te maak
Eenvoudige voorstel van ‘n presies sistem
Deel van die realitiet dat die ingenieur will hê
Sistem: grond-plant-atmofeer kontinuum (SPAC)
atmosfeer
plant
grond
irrigationrainfall
capillaryrise
deeppercolation
evapo-transpiration
runoff
kan vinnig bestuur van lande beplan toets goeie strategie in ander plekke / gewasse formuleer gids
Verduideliking van model (SPAC)
Kalibrasie/Validasie
Veldproewe
Kalibrasie/Validasie van model
Om opbrengs teen water te evalueer
irrigation (I)rainfall (P)
capillaryrise deep
percolation
sto
r ed
so
il w
at e
r (m
m)
field capacity
threshold
wilting point
evapo-transpiration
(ET)
(CR)
(DP)0.0
Om opbrengs teen oor water te meetVoor goeie voorstelle kan gemaak word, proewe moet oor aantal jare (met verskillende klimaat); ‘n reeks plant datuums; verkillende omgewingtoestande ens gedoen word.
Soek ‘n model wat kan: is gebaseer op akuraat plantphisiologiese & grondwater balans & prosese
AquaCrop maak gebruik van ‘n relatiewe klien hoeveelheid parameters (explicit and mostly intuitive) en probeer om balans tussen eenvoudigheid, akuraatheid en ‘robustness’ te vind.
model om gewas opbrengs reaksie met water te skat
benoodig net beskikbare insette (klimaat, grond, gewas & velddata)
is maklik om te gebruik
kan maklike geverifikeer word (eenvoudig veld meetings simulasie resultate)
is toepaslike oor bree veld met aanvaarbaar akuratheid
tyd
1. Gewas Ontwikkeling
Blaardak groei
maksimum blaardak bedekking blaardak
verouderingbogrond
ondergrondopervlakte
Wortelzoon toeneem
maksimum “effektiewe” worteldiepte is bereik
In plaas van BlaarAreaIndeks (Leaf Area Index) (LAI)
AquaCrop gebruik groenblaardakbedekking (green canopy cover) (CC)
CC = Grond oppervlakte bedek deur groenblaardak
eenheid grond oppervlakte area
Reeks van 0 (skoon grond opervlakte) na 1 (volle blaardakbedekking)
0 % 100 %
eenheid grond oppervlakte area
Grond oppervlakte bedek deur
groenblaardak
Canopy Cover / Blaardak meeting ?
Neem oorhoofse
foto
Meet CC van af foto (sagtewaarde)
groenblaardakbedekking(CC)
3 %19 %
75 %
90 %
Winterkoring (Walshoutem, Belgium)
20 Oktober 2008
16 Maart 2009
14 April 2009
12 Mei 2009
Blaardak ontwikkeling (geen stremming nie)
Gewas karakteries (insette)
maksimum blaardak
veroudering
logisties vergelyking
Groei siklus (dae) plant Volwasse gewas
irrigation (I)rainfall (P)
capillaryrise deep
percolation
sto
red
so
il w
at e
r (m
m)
field capacity
threshold
wilting point
evapo-transpiration
(ET)
(CR)
(DP)0.0
Water stremming(bo) drumpel
1
3
Blaar groei
Blaardak veroudering
FC
PWP
irrigation (I)rainfall (P)
capillaryrise deep
percolation
sto
red
so
il w
at e
r (m
m)
field capacity
threshold
wilting point
evapo-transpiration
(ET)
(CR)
(DP)0.0
Blaar groei
Blaardak veroudering
CCBlaardak ontwikkeling
Wortel ontwikkeling
Zr
tyd
tyd
Grond water balans
irrigation (I)rainfall (P)
capillaryrise deep
percolation
sto
red
so
il w
at e
r (m
m)
field capacity
threshold
wilting point
evapo-transpiration
(ET)
(CR)
(DP)0.0
Blaar groei
Blaardak veroudering
CCBlaardak ontwikkeling
Wortel ontwikkeling
Zr
tyd
tyd
Grond water balans
Blaardak ontwikkeling(geen waterstreming)
Blaardak ontwikkeling(werklike grondwater toestande)
Groen Blaardak Bedekking
time
1
24
5
simulationGrondwater balans
reggestel blaardak bedekking vir waterstreming
3CC
Tyd
irrigation (I)rainfall (P)
capillaryrise deep
percolation
sto
red
so
il w
at e
r (m
m)
field capacity
threshold
wilting point
evapo-transpiration
(ET)
(CR)
(DP)0.0
Blaar groei
Blaardak veroudering
CCBlaardak ontwikkeling
Wortel ontwikkeling
Zr
tyd
tyd
Grond water balans
2. Gewas Transpirasietranspirasie
1. Gewas Ontwikkeling
Transpirasie = Kcb x ETo
geen waterstremming nie
Verwysings-evapotranspirasie
gewaskoeficient
weer toestande
Karakter van transpiring gewas
Verdampings krag van atmosfeer
gewas karakteries (integrasie van efekte van karakter waar gewas verskil van verwysingsgras)
groenblaardakbedekking = CC
irrigation (I)rainfall (P)
capillaryrise deep
percolation
sto
red
so
il w
at e
r (m
m)
field capacity
threshold
wilting point
evapo-transpiration
(ET)
(CR)
(DP)0.0
Blaar groei
Blaardak veroudering
CCBlaardak ontwikkeling
Wortel ontwikkeling
Zr
tyd
tyd
Grond water balans
Tr = Kcb ETo
CC
irrigation (I)rainfall (P)
capillaryrise deep
percolation
sto
red
so
il w
at e
r (m
m)
field capacity
threshold
wilting point
evapo-transpiration
(ET)
(CR)
(DP)0.0
Water stremming(bo) drumpelpunt
1
3
Blaar groei
Blaardak veroudering
FC
PWP
stomata sluiting2
irrigation (I)rainfall (P)
capillaryrise deep
percolation
sto
red
so
il w
at e
r (m
m)
field capacity
threshold
wilting point
evapo-transpiration
(ET)
(CR)
(DP)0.0
Blaar groei
Blaardak veroudering
CCBlaardak ontwikkeling
Wortel ontwikkeling
Zr
tyd
tyd
Grond water balans
CC
stomata sluiting
Tr = Ks Kcb ETo
H O2
CO2
2. Gewas Transpirasie3. Biomassa produksie
Plantblare absorbeer CO2 van uit atmosfeer deur gaatjies genoem stomata / huidmondtjies en, selfde tyd, water verdamp van blare in proses genoem transpirasie. Fotosintesis verander die geabsorbeerde CO2 na koelhidrate wat bousteen van die plant biomassa is.
1. Gewas Ontwikkeling
Daar is ‘n stabel & konserwetiewe verhouding tussen
B:
bo
gro
nd
bio
mas
sa (
kg/m
2)
Σ(Tr) : kumulatiewe gewas transpirasie (mm water)
WP
Biomassa (B) & kumulatiewe transpirasie ( Σ(Tr) )
biomassa waterproduktiewiteit
kg(biomass) / m2.mm(water)
ETc (mm x 1000)0.0 0.3 0.6 0.9
Bio
ma
ss
(kg
m-2
)
0
1
2
3
SorghumSunflowerChickpeaWheat
Σ(Tr) mm x 1000
Verdeel Tr deur EToWP is genormaliseer vir klimaat
WP WP*
(T/ETo)
0 40 80 120 160
Ab
ove
-gro
un
d b
iom
ass (
g m
-2)
0
1000
2000
3000
Sunflower N0
WheatChickpea
Sunflower N1
Sorghum N0
Sorghum N1
Data from Steduto & Albrizio, 2005, Agric. & For. Meteor. Σ(Tr/ETo)
WP
WP*
WP*
Gewasgroepe met dieselfde WP*
C3: WP* = 15 - 2
0 g/m2
C4: W
P* = 3
0 - 3
5 g/
m2
For spesiefiek klimaat toestande
WP* vir mielies
Data from ICASA, IAEA & UniMelb
0
5000
10000
15000
20000
25000
30000
35000
0 20 40 60 80 100 120
Bio
mas
sa (k
g/h
a)
(ETa/ETo)
China99Ghana01Hawaii83Hungary 0NHungary 175 kgN/haGainesville irrigated 400NSpain96Full irrigationSpain96 50%irriC4 29kg/ha.mm line
Mielies
Σ(Tr/ETo)
irrigation (I)rainfall (P)
capillaryrise deep
percolation
sto
red
so
il w
at e
r (m
m)
field capacity
threshold
wilting point
evapo-transpiration
(ET)
(CR)
(DP)0.0
Blaar groei
Blaardak veroudering
CCBlaardak ontwikkeling
Wortel ontwikkeling
Zr
tyd
tyd
Grond water balans
CC
stomata sluiting
Water Produktiewetiet
B = WP* x Σ ( )
WP*
TrETo
Tr = Ks Kcb ETo
Biomassa
1. Gewas ontwikkeling
2. Gewas Transpirasie3. Biomassa produsie
4. Opbrengs formulasie
irrigation (I)rainfall (P)
capillaryrise deep
percolation
sto
red
so
il w
at e
r (m
m)
field capacity
threshold
wilting point
evapo-transpiration
(ET)
(CR)
(DP)0.0
Blaar groei
Blaardak veroudering
CCBlaardak ontwikkeling
Wortel ontwikkeling
Zr
tyd
tyd
Grond water balans
CC
stomata sluiting
Water Productivity
B = WP* x Σ ( )
WP*
TrETo
Tr = Ks Kcb ETo
Biomassa
Biomassa
B = totaal bogrond biomassa stam, blare, blomme, graan, …
Harvest Index (HI) = (oesindeks)fraksie van B wat die oesbare produk is
Opbrengs
Y
irrigation (I)rainfall (P)
capillaryrise deep
percolation
sto
red
so
il w
at e
r (m
m)
field capacity
threshold
wilting point
evapo-transpiration
(ET)
(CR)
(DP)0.0
B = WP* x Σ ( )
Canopy development
Root development
BiomassaZr
time
soil water balanceWP* Water
Productivity
leaf expansion
canopy senescence
root zone exapansion
Y
Harvest Index
Opbrengs
Tr = Ks Kcb ETo
TrETo
time
CC
CC
HI
stomatal closure
1. Gewas ontwikkeling
2. Gewas transpirasie3. Biomassa produksie
4. Opbrengs formalasie
5. Insetdata
ETo (reference evapotranspiration)
grass reference surface(well watered, optimal growing)
ETo calculatorETo computed from meteorological datawith the FAO Penman Monteith equation
ETo (reference evapotranspiration)
Rainfall
Air temperature (Tmin and Tmax)
ETo (reference evapotranspiration)
Rainfall
Air temperature (Tmin and Tmax)
[CO2] (for future climates)
1990 2000 2010 2020 2030 2040 2050 20600
100
200
300
400
500
600
year
CO2 concentration (ppm)
Affects:- Crop development- Crop transpiration- Biomass production- Harvest Index
Crop characteristicsCanopy development (non-limiting conditions)
WP*
Crop characteristics
Cotton, Maize, Paddy Rice, Potato, Quinoa, Soybean, Tomato, Sunflower, Sugarbeet, Wheat
Calibrated crops
Canopy development (non-limiting conditions)
local callibration (variety, sowing density)
adjust
Soil characteristicsirrigation (I)
rainfall (P)
capillaryrise deep
percolation
sto
red
so
il w
at e
r (m
m)
field capacity
threshold
wilting point
evapo-transpiration
(ET)
(CR)
(DP)0.0
saturationfield capacity
wilting point
saturated hydraulic conductivity
Indicative valueshttp://hydrolab.arsusda.gov/soilwater/Index.htm
Irrigation schedule• when• how much
Irrigation management
Irrigation method
Generate irrigation schedule• when = time criterion• how much = depth criterion
Field management
Field surface practices
Field management
Field surface practices Mulches
Field management
Field surface practices
Level of soil fertility
Mulches
– non limiting– near optimal– moderate– poor
Automatic adjustment of crop development
The model is useful to develop irrigation strategies under water deficit conditions to study the effect of location, soil type, sowing date, … to study the effect of various land management techniques, to predict climate change impacts on crop production, etc.
rainfed irrigation
conditions
1. Gewas ontwikkeling
2. Gewas transpirasie3. Biomassa produksie
4. Opbrengs formalasie
5. Insetdata
6. Beperkende faktore
6. Beperkende faktoreirrigation (I)
rainfall (P)
capillaryrise deep
percolation
sto
red
so
il w
at e
r (m
m)
field capacity
threshold
wilting point
evapo-transpiration
(ET)
(CR)
(DP)0.0
waterkwaliteit
uniformheid van landerye jaarlikse gewasse