christensenetal2003 {drc}R Documentation

Potency of two herbicides

Description

Data are from an experiment, comparing the potency of the two herbicides glyphosate and bentazone in Sinapis alba.

Usage

data(christensenetal2003)

Format

A data frame with 68 observations on the following 3 variables.

Dose
a numeric vector giving the dose in g/ha
Herbicide
a factor with levels Bentazone Glyphosate
DryMatter
a numeric vector containing the response

Details

The lower and upper limits for the two herbicides can be assumed identical, whereas slopes and ED50 values are different (in the log-logistic model).

Source

The dataset is analysed in Christensen et al (2003).

References

Christensen, M. G. and Teicher, H. B. and Streibig, J. C. (2003) Linking fluorescence induction curve and biomass in herbicide screening, Pest Management Science, 59, 1303–1310.

Examples


## Fitting a log-logistic model with
##  common lower and upper limits
model1<-multdrc(DryMatter~Dose, Herbicide, data=christensenetal2003,
collapse=data.frame(Herbicide,1,1,Herbicide), boxcox=TRUE) 

## Plotting fitted curve and data
plot(model1)

rm(model1)

[Package drc version 0.9-0 Index]