Published online by Cambridge University Press: 10 December 2009
Introduction
Fundamentally, biogeochemical cycling involves the transformation of compounds between various forms, and a movement of such compounds within and between compartments of the biosphere and geosphere. These processes operate across a wide range of spatial and temporal scales, from micrometres to kilometres, from seconds to centuries. In terrestrial systems, transformations and movement of materials below-ground are governed by the spatial organization of the soil system, and particularly the architecture of the pore network. This ‘inner space’ provides the physical framework in and through which the majority of soil-based processes occur. The labyrinthine nature of the pore network, and the exchange properties of associated surfaces, strongly modulates the transport of materials through the soil matrix. From a physicochemical perspective soil structure generally retards transport processes for two main reasons: the complex geometry of the pore network increases path lengths, both for diffusive and bulk-flow movement; and charged mineral and organic constituents in the soil act as exchange surfaces which bind transportable compounds to varying degrees. Transport processes may also be accelerated by structural properties, for example if solutes or particulates are carried via preferential and bypass-flow channels of water through macropores.
Soil organisms play a key role in driving terrestrial nutrient cycling, and play both direct and indirect roles in effecting and affecting transport processes. Fungi contribute a particularly wide range of functions relating to nutrient cycling.
To save this book to your Kindle, first ensure [email protected] is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.