DECOMPOSITION AND NUTRIENT DYNAMICS OF HARDWOOD LEAF-LITTER IN THE FERNOW WHOLE-WATERSHED ACIDIFICATION EXPERIMENT

Two watersheds are part of an on-going long-term artificial acidificat ion experiment: the treatment watershed (WS3) has received 60.5 kg S h a(-1) year(-1) and 54 kg N ha(-1) year(-1) via aerial applications of ammonium sulfate fertilizer since 1989. After 3 years of treatment, fr eshly fallen leaves of four hardwood tree species (Liriodendron tulipi fera, Prunus serotina, Acer saccharum, and Berula lenta) were collecte d and placed in litter bags, which were placed in stands in the treatm ent and control watersheds. Decay rates differed for L. tulipifera, Pr unus serotina, and B. lenta between the two watersheds, with litter fr om WS3 decaying more slowly over the 2 year study period than litter f rom the control watershed. Initial concentrations of N, Ca, and K diff ered between treatment and control watersheds, but these differences d isappeared after 2 years. Nutrient loss rates did not vary with treatm ent.