Pedodiversity is the variation of soil properties (usually characterised by soil classes) within an area. Pedodiversity studies were first started by analyzing soil series–area relationships (Beckett and Bie, 1978). According to Guo et al. (2003) the term pedodiversity was developed by McBratney (1992) who discussed landscape preservation strategies based on pedodiversity. Recently, examinations of pedodiversity using indices commonly used to characterize bio-diversity have been made
Ibáñez et al. (1995) first introduced ecological diversity indices as measures of pedodiversity. They include Species richness, , and Shannon index. Richness is the number of different soil types, which is the number of soil classes at particular level in a taxonomic system. Abundance is defined as the distribution of the number of soil individuals.
Just as biologists and ecologists talk about biodiversity, geologists on geodiversity, soil scientists can talk about pedodiversity. Pedodiversity has some overlap with biodiversity as soil contains organisms. Pedodiversity is a measure of soil variation, and pedodiversity is a function of soil formation.
Pedodiversity can be thought as a way to preserve, or even reconstruct, the soil cover. Just as biologists argue that organisms need to be maintained, soil scientists can argue that preserving soil will maintain organisms as well as other unique soil materials equally crucial in insuring our future wellbeing. In areas which have been degraded it will become important to reconstruct the variation. A quantitative knowledge of natural pedodiversity will ease the task of the person who attempts to rebuild quasi-natural soil systems.
Soil scientists have pragmatically adapted the concept of biodiversity and used diversity index such as Shannon index using taxa from well-accepted international soil classification systems.
Jonathan Phillips showed that in eastern North Carolina intrinsic variability within homogeneous landscape units is more important in determining the total pedodiversity of the study area than is the extrinsic variability associated with measurable differences in topography, parent material, and vegetation/land use. In another study, they found that soils in Ouachita Mountains of Arkansas vary considerably within small more-or-less homogeneous areas, and richness–area analysis shows that the overall pattern of pedodiversity is dominated by local, intrinsic (within-plot) variability as opposed to between-plot variability. This is consistent with variation controlled mainly by individual trees and local lithological variations. Given the criteria used to distinguish among soil types, biomechanical as opposed to chemical and hydrological effects of trees are indicated. Results also suggest divergent evolution whereby the pedologic effects of trees are large and long-lived relative to the magnitude of the initial effects and lifespan of the plants.