Soil Organic Carbon Distribution in Aggregates and Primary Particle Fractions as Influenced by Erosion Phases and Landscape Position

The detrimental consequences of accelerated soil erosion from agricultural land leading to degradation of soil resources, reduced productivity, and adverse environmental impact have received much attention since the 1970s. Landscape position influences the nature and extent of erosion or deposition processes occurring at any given location in a field. The degree of past erosion affects the distribution of soil organic carbon (SOC) in the soil profile and among various aggregate and primary particle size-fractions. The chapter aims to identify principal mechanisms of C sequestration and to assess the relative importance of severity of erosion on partitioning of SOC contained in macroaggregates among smaller aggregate and primary particle size-fractions. Erosion is likely to lead to a gradual depletion of SOC by exposing the stable carbon pool in microaggregates of not only the surface layer but subsoil as well, to degradative processes by disrupting macroaggregates and removal of successive layers of soil.