Measurement and modelling of soil organic matter decomposition using biochemical indicators

Abstract

One problem with many mechanistic models of soil organic matter decomposition and nitrogen MIT is that the conceptual pools used to represent fractions of material which decompose at different rates are not easy to measure directly. A range of biochemical techniques for fractionating soil organic matter and the microbial biomass are presented in this paper and their potential for inclusion in models of carbon and nitrogen turnover discussed. These techniques include analysis of lignin de-polymerisation, a quantification of total and labile carbohydrate and a fractionation of the microbial biomass between fungi and bacteria using phospholipid and ergosterol analysis. Preliminary comparisons between the biochemical signatures of different soil types under different land uses are discussed in relation to the physical and biological factors affecting decomposition rates.