Models that Describe Litter Decomposition

Abstract

The graphs for accumulated litter mass loss vs time form different patterns, which may be described using a few simple mathematical functions. Generally we may state that litter may decompose completely or leave a stabilized residue, which may decompose very slowly. Complete decomposition may be described using the single exponential, with a constant rate, the same function as for radioactive decay. In another approach the complete decomposition may be described in two steps using a two-factorial ‘double exponential’ with part of the litter decomposing at a high and part at a lower rate. A flexible, decreasing rate and a calculable stabilized residue are described using an asymptotic function. The decreasing decomposition rate allows the calculation of a limit value, often between 50 and 100% accumulated mass loss, using the decomposition rate of zero. Although this estimated rate gives an extremely slowly decomposing ‘stable’ fraction there are few studies on the stability of this residue. Possibly a raised nitrogen concentration may be stabilizing.