Figure 3.

The total dry weight of mature plants after the application of two pre‐emergence herbicides on soil with varying levels of organic matter: (a) low, (b) medium and (c) high. Points indicate the response of each sample (flufenacet in blue; pendimethalin in red) and the fitted model is shown by a solid black line. (The fit of the model was significantly improved by allowing separate lines to be fitted to each soil type, yet there was no significant difference between the two active ingredients, so a single line was fitted across both herbicides.) Dose is given as a proportion of recommended field rate.