Main plots were pasture composition (BFT, BFT+TF, RBFT and RBFT+TF).
Condensed tannin concentrations of birdsfoot trefoil differed greatly among in pasture composition types (P < 0.05), an exception being the similarity between RBFT in pure stands and mixtures.
Assuming the optimum condensed tannin concentration for ruminant livestock occurs between 20 and 40 g CE [kg.sup.-1] DM, as proposed by Barry and Manley, 1986; Aerts et al., 1999, neither BFT nor RBFT appeared to have a comparative nutritional advantage.
Condensed Tannin in BFT and RBFT from Monocultures vs.
Condensed tannin concentration of RBFT was not affected by growing in a tall fescue mixture, possibly because concentrations were already very high in RBFT (Fig.
The fact that tall fescue affected BFT tannins but not RBFT tannins was not likely related to differences in legume proportion.
In 1995, both non-clipped RBFT and non-clipped BFT had more root mass than their clipped counterparts did on 12 and 26 September and 10 October, but by 24 October, all four treatments were again equal (avg.
Both RBFT and BFT showed little change in taproot TNC concentration from early-July through August of either year (Fig.
In 1994, non-clipped RBFT went from 117 g [kg.sup.-1] on 14 September to over 220 g [kg.sup.-1] by 26 October.
In 1995, non-clipped RBFT went from 158 g [kg.sup.-1] on 12 September, to 249 g [kg.sup.-1] by 24 October; non-clipped BFT went from 75 to 191 g [kg.sup.-1] over the same period.
The elevated levels of TNC in RBFT taproots combined with its lower shoot mass, suggests that RBFT partitions relatively more photosynthate to belowground organs, either for storage or to support rhizome growth.
In mid-September of both years, RBFT plants began to form new rhizomes.