wofost_model {Rwofost}

WOFOST crop growth model

Description

Create a WOFOST crop growth model object. Trhough this interface, you first create a model object and then you run it. The advantage is that you can easily change single parameters of the model and run the model again.

Usage

wofost_model(crop, weather, soil, control)
run(x, ...)
crop(x) <- value
soil(x) <- value
control(x) <- value
weather(x) <- value
force(x) <- value

Arguments

crop

list. Crop parameters

weather

data.frame with weather data. See Details

soil

list. Soil parameters

control

list. Model control options

value

crop, weather, soil, or control data, as above; or a data.frame for "force"

x

WOFOST model

...

additiontal arguments. stopError(logica). If an error occurs and stopError is TRUE, and error message is given. Otherwise, a warning is given and some simulation data (up till when the error occurred) may be returned

Details

The weather data must be passed as a data.frame with the following variables and units.

	variable	description	class / unit
	date	"Date" class variable	-
	srad	Solar radiation	kJ m-2 day-1
	tmin	Minimum temperature	degrees C
	tmax	Maximum temperature	degrees C
	vapr	Vapor pressure	kPa
	wind	Wind speed	m s-1
	prec	Precipitation	mm day-1

Note that there should not be any time gaps between the days in the data.frame

Value

WofostModel object

References

Van Diepen, C.A., J. Wolf, and H van Keulen, 1989. WOFOST: a simulation model of crop production. Soil Use and Management, 5: 16-24

Van Keulen, H. and J. Wolf, 1986. Modelling of agricultural production : weather, soils and crops. http://edepot.wur.nl/168025

Examples

# weather data
f <- system.file("extdata/Netherlands_Swifterbant.csv", package="meteor")
w <- read.csv(f)
w$date <- as.Date(w$date)

crop <- wofost_crop("barley")
soil <- wofost_soil("ec1")
contr <- wofost_control()

contr$modelstart <- as.Date("1980-02-06")
contr$latitude=52.57
contr$elevation=50

# create model
m <- wofost_model(crop, w, soil, contr)

# run model
x <- run(m)
plot(x[,"date"], x[, "LAI"], cex=.5)

# make a change
m$control$modelstart = as.Date("1980-02-20")

# run model again
y <- run(m)
lines(y[,"date"], y[, "LAI"], col="red")

# change the crop 
crop(m) <- wofost_crop("potato_704") 
p <- run(m)
lines(p[,"date"], p[, "LAI"], col="blue")