S.alba {drc} | R Documentation |
Data are from an experiment, comparing the potency of the two herbicides glyphosate and bentazone in Sinapis alba.
data(S.alba)
A data frame with 68 observations on the following 3 variables.
Dose
Herbicide
Bentazone
Glyphosate
DryMatter
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).
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.
See the examples in the examples sections in multdrc
and SI
.
## Fitting a log-logistic model with ## common lower and upper limits model1 <- drm(DryMatter~Dose, Herbicide, data=S.alba, fct = LL.4(), pmodels=data.frame(Herbicide,1,1,Herbicide), adjust="bc1") ## Plotting fitted curve and data plot(model1)