A simple method for calculating decomposition and accumulation of ‘young’ soil organic matter

In previous simple models describing decomposition of organic matter, the rate of decomposition was usually assumed to be constant. Experimental evidence has shown this is not true. The objective of this study was therefore to find a relationship between decomposition rate and time. This resulted in an equation (Eqn 5), that can be used for many types of organic materials, provided their ‘apparent initial age’ is known. This age is related to the humification coefficient and varies from 1 year for green matter to 14 years for some peats. Formulas to calculate accumulation and decomposition of ‘young’ soil organic matter were also derived.