LONG-TERM STUDY OF LITTER DECOMPOSITION ON A PENNINE NEAT BOG - WHICHREGRESSION

It is estimated that in the northern hemisphere one-third of the world pool of soil carbon is contained in peat resulting from an incomplete decomposition of plant remains. The time course for the decomposition of the predominant plant litters on a Pennine moorland in northern En gland is reported for a study extending over 23 years. Spatial variati on of the weight remaining of decomposing litters increased with time. This experimental study gave an age for the upper layers of the bog a nd a curve for long-term decay based on direct observation rather than inferred from profile samples or from short-term observations. It sho wed that short-term observations can give misleading results in the lo ng term, with a variety of litters with differing early decay rates ul timately making a similar contribution to accumulation. Spatial variat ion of the weight remaining of the decomposing litters increased with time, so that variation within micro-environments, or within apparantl y uniform substrates, may contribute significantly to organic matter a ccumulation. An asymptotic curve best described the long-term course o f decomposition leading to the accumulation of peat. The use of the mo del for the three litter types, Calluna vulgaris, Eriophorum vaginatum and Rubus chamaemorus, is described and the implication of the result s for modelling of organic matter accumulation are then discussed.