Many terrestrial, freshwater and coastal environments receive abundant plant litter as an important source of carbon, nitrogen and phosphorus for microorganisms and detritivores. Therefore, the dynamics of these elemental pools in litter provide important ecological information on carbon and nutrient cycling. This chapter describes methods for quantifying carbon, nitrogen and phosphorus in decomposing plant litter. The collected material is first ground to a fine powder, which is used to analyse all three elements. The subsequent phosphorus analysis involves an acid or alkaline digestion to transform all phosphorus compounds to ortho-phosphate, which is then quantified spectrophotometrically by the ascorbic acid method. The analysis of total nitrogen starts with an acid digestion of the litter and reduction of all oxidized nitrogen species to ammonia, which is also quantified spectrophotometrically. A simple approach to estimate the total carbon content of plant litter consists in combusting ground samples at 500 °C and measuring the mass loss on ignition (LOI), where 50% of the loss is assumed to be carbon. Alternatively, carbon and nitrogen are determined on a CHN elemental analyser. Major advantages of that approach are that the analyses require very little plant material and that both elements are quantified in the same sample.
|Title of host publication||Methods to Study Litter Decomposition : A Practical Guide|
|Editors||Felix Bärlocher, Mark O. Gessner, Manuel A.S. Graça|
|Publication status||Published - 2020|