Agriculture Reference
In-Depth Information
3.2.2.2
Availability in time
Fresh litter inputs are normally seasonal, even in humid tropical forests (see, for
example, Spain, 1984) (Chapter IV.2.6). The general pattern of availability is a rapid
accumulation of fresh material during the dry or cold season followed by a progressive
decrease in the standing crop biomass up to the start of the next dry or cold season.
Where decomposition is rapid, as in some temperate mull systems and many lowland
tropical rainforests, most of the annual litter input may be decomposed or exported in as
little as six months. Under these circumstances, litter is defined as a rapidly-diminishing
resource,.according to Price (1984).
Conversely, in environments where decomposition is slow, the O horizon may
comprise several layers corresponding to the accumulated remains of successive yearly
inputs. Under such circumstances, litter is considered a regularly-renewed resource,
regardless of the chemical differences between successive layers. This situation is
illustrated in Figure I.42 (Garay
et al.,
1986a).
