The role played by microorganisms in the biogenesis of soil cracks: Importance of substrate quantity and quality

The development of cracks in soils has a significant effect on important soil processes such as gaseous diffusion, water flow and root development. It is the heterogeneity and tortuosity of the resulting cracks which are important as they influence and control such processes. The microbial contribution to crack formation was therefore assessed by quantifying the heterogeneity and connectivity of cracks which developed following the addition of substrates differing in quantity and quality to a sandy loam soil. The heterogeneity and connectivity of the cracks was assessed using probability and Monte Carlo techniques respectively, which provided an estimate of how the occurrence of cracks varied with sample area and the nature of the route taken by a random walker in such a space. Increasing the amount of glucose added resulted in significantly (P