Agriculture Reference
In-Depth Information
3.2.2
SURFACE LITTER
3.2.2.1
Quality
The dead leaves, wood and reproductive structures which form the major part of
the surface litter differ strongly in quality both within and between species. Quality also
depends on soil nutrient status and changes markedly with time, as decomposition proceeds.
Composition of fresh litter
Leaf litter may be broadly classified as being of low to moderate accessibility. Its quality
is positively related to its concentrations of soluble carbohydrates, hemicellulose, nitrogen
and other nutrient elements and negatively to its concentrations of lignin, cellulose and
secondary plant compounds, including polyphenols and other toxic modifiers
Fresh leaf materials usually possess high concentrations of soluble carbohydrates,
mainly reducing sugars,
e.g.,
15 to 18 % in savanna grasses (Lavelle
et al.,
1983a), 7.2 %
in oak leaves (Waksman, 1952) and 29.6-33.8 % in the leaves of three
Salix
species
(Slapokas, 1991). However, concentrations of these substances may decrease sharply
