Phytometric estimation of fertility of waterlogged rich-fen peats usingEpilobium hirsutum L.

Summary The above-ground net production of herbaceous vegetation in 16 stands of waterlogged rich fen in Broadland, Norfolk UK, has been compared with the growth ofEpilobium hirsutum seedlings (in controlled environment) on replicate peat samples from each site and with the chemical composition of extracts from sub-samples of each peat (Ca, Mg, Na, K, Fe, Mn, inorganic P, inorganic N). There were no consistent or significant relationships between measured concentrations of major nutrients (K, N, P) in peat samples and netin situ production of the vegetation or with growth ofE. hirsutum seedlings on each peat. There was a strong, significant (p<0.001) relationship between above ground productionin situ and growth ofE. hirsutum seedlings. Seedling growth thus provided a simple, sensitive phytometric measure of fertility of the waterlogged peats (pH range 6.0–7.0). One possible limitation is the apparent sensitivity ofE. hirsutum seedlings to high manganese concentrations.