QUANTIFICATION OF FUNGAL MORPHOLOGY, GASEOUS TRANSPORT AND MICROBIAL DYNAMICS IN SOIL - AN INTEGRATED FRAMEWORK UTILIZING FRACTAL GEOMETRY

The consequences of heterogeneous structure for nutrient acquisition by soil fungi, microbial dynamics and transport in soil are studied. Fractal geometry provides the unifying theme and forms the basis of a theoretical framework for studying dynamics in heterogenous media. The interpretation of foraging strategies of soil fungi are presented which suggest that the processes governing branching and hyphal mass distribution are independent. Classical diffusion is shown to be inappropriate for the study of diffusion in heterogeneous soil and a new theory is proposed which incorporates heterogeneity and pore tortuosity. The consequences of structure for microbial spatial and temporal dynamics are examined and it is found that an understanding of these and related processes such as nutrient cycling must include the role of soil structure. While stressing the need to appreciate the relevance of the theory to any particular application, it is shown that quantitative fractal geometry can yield insights into the mechanism whereby spatial organisation influences the interaction between structure and biotic processes in the soil.