Figure 1.

Mean aboveground productivity of (A) plots for individual mixtures averaged over the 3 years of the trial and (B) plots based on perennial ryegrass (Lolium perenne, RG) or tall fescue (Festuca arundinacea, TF) either with or without the forbs plantain (Plantago lanceolata) and chicory (Chicorium intybus) in each year of the trial. Error bars show the standard error. Letters assigned to mixtures indicate significant differences using Tukey's honest significant difference, with mixtures not sharing any letters being significantly different from each other. Sown species composition of each mixture code is given in Table 1.