ICBA-IAEA - Training on water management and use of crop simulation model- richard soppe, icba
Crop growth simulation models - University of California,...
Transcript of Crop growth simulation models - University of California,...
Crop growth simulation models
Camila Bonilla Cedrez
PhD candidate
University of California, Davis
Temperature
Radiation
Precipitation
Soil
Runoff
WHC
Evaporation
MicrobesNPK
SOM pH
NEVER ENDS !!!
Crop growth simulation: a tool of (Agro-) systems analysis
• System: limited part of reality that contains interrelated elements
• Model: a simplified representation of a system
Mechanistic models
Explaining the growth course from the underlying physiological processes in
relation to the environment
Types of crop simulation models
Crop growth simulation model: helps estimate crop yield as a function of weather conditions, soil conditions, and crop management practices
Statistical models
Describing the growth course with some empirical function
Why is crop growth simulation useful?
Source: van Ittersum et al. 2013
Production level (t/ha)
Pro
du
ctio
n s
itu
atio
n Yield Potential
Attainable
Actual
Defining factors
Limiting factors
Reducing factors
CO2Radiation
TemperatureCultivar features
WaterNutrients
WeedsPests and diseases
Pollutants
QUEFTS: Quantitative Evaluation of the Fertility of Tropical Soils
Smaling & Janssen, 1993. Sattari et al. 2014
Chemical soil properties Fertilizers * recovery
Potential supply of nutrients (N, P, K)
Actual uptakes
Possible yield ranges
Combining yield ranges to one Final yield
STEP 1
STEP 2
STEP 3
STEP 4
WOFOST: WOrld FOod STudies
• Is a dynamic explanatory model
State Variables Driving Variables Rate Variables
Quantitativei.e. biomass
External factors on the syst.
i.e. weather
Rate at which the state variables change at certain
moment
STATE (t + Δt) = State (t) + Rate (t) * Δt
RATE = State (t) * constant
WOFOST: WOrld FOod STudies
INPUT/OUTPUT: Crop, Soil and Weather
Daily weather data
INPUT
Soil data
Crop parameters
MODEL Yield level
OUTPUT
Spatial estimation of yield levels
Estimation of potential yield (g/m2) for 1 year for wheat for Tanzania
Known Daily Weather Station
A B
C
?
The problem
Daily weather station density is low
Sketch. No scales
How to estimate yield levels where there are no
weather stations?
How to estimate yield levels where there are no
weather stations?
Known Daily Weather Station
Possible methods:
1. Nearest neighbor2. Interpolate weather3. Interpolate yield with co-variables4. Daily weather simulator5. Metamodel
Sketch. No scales
A B
C
?
Nearest Neighbor
Known Daily Weather Station
Distance1 < Distance2 < Distance3
Sketch. No scales
d1d2
d3
AB
C
?
Nearest Neighbor
Known Daily Weather Station
A
B
C
?
Run crop model
Nearest neighbor
Distance1 < Distance2 < Distance3
x1, y1 x2, y2
x3, y3
?
Interpolate Weather
Known Daily Weather Station
30 (years) × 365 (days) × 5 (weather variables) = 54750 interpolations
A
C
B
?
Interpolate daily weather data
Run crop model
Fischer et al., 2002; Lobell & Field, 2007; Priya & Shibasaki, 2001
Interpolate Yield with co-variables
Known Daily Weather Station
AB
C
?
Run crop model
Interpolate with co-variables
De Wolf et al., 2002; Wu et al., 2006
Known Daily Weather Station
A B
C
?
The problem
Daily weather station density is low
Climate Data: High spatial resolution
How to estimate yield levels where there are no
weather stations?
Climate data
Daily weather simulator
Run crop model
Aggregate prediction
Run crop model Weather data
Metamodel
Andarzian et al., 2008; Deryng et al., 2011; Hijmans et al., 2000; Neumann et al., 2010; Nohebel, 1994; Perlman et al., 2014; Sparks et al., 2011; Van Bussel et al., 2011; Wilks & Wilby, 1999
Climate data
Prediction