Variable Herbicide Perfomance

Appendix A.  List of parameters included in statistical analysisa.

Observed factors Observed covariates Interpolated covariates
Crop planting date Temperature at spraying Max. temp. on spray date
Spray date Wind speed Min. temp. on spray date
Date of evaluation Relative humidy at spraying Rainfall on spray date
Spray additive used Days from spraying to evaluation Evaporation on spray date
Location in Australia Herbicide dose Temp. sum for 30 days prior to applic.
  Wheat growth stage Temp. sum from sowing to spraying
  Wheat density Days prior to applic. since last rainfall
  Wild oat growth stage Min. temp. sum for 7 days prior to app.
  Wild oat density Min. temp sum for 7 days after app.
  Spray volume Min. temp. sum for 7 days before and after app.
  Wheat yield Soil moisture deficit at app.
    Soil moisture deficit 10 days prior to app.
    Soil moisture deficit 10 days following app.

aR. W. Medd et al.  2001. Determination of envirnoment-specific dose-response relationships for clodinafop-propargyl on Avena spp.  Weed Res. 41:351-368.