Pouyat (1991) proposed that human influences necessitate the inclusion of a separate factor because humans, unlike other organisms, are purposeful manipulators of soils (Bidwell and Hole, 1965). Furthermore,human effects on soils occur on different spatio-temporal scales than those of other organisms,primarily because of the use of technology by humans. Technology has supported an exponential increase in human population growth and has increased the extent and magnitude of our disruption of the landscape (Ehrlich et al., 1976).
The conceptual model of soil-forming factors was described by Dokuchaev in 1879 and Hilgard in
1892 (Arnold, 1983). In 1941, Jenny proposed the factoral model of soil genesis as a athematical
expression in which each factor acted independently of the others such that the manipulation of one factor does not affect another. Likewise, the anthropogenic factor can act independently of the other factors. For example, if a human-induced catastrophic event occurs in which the soil profile is disrupted, the human impact on that soil occurred independently of the other soil forming factors. In this case, however, the temporal scale of the human modification is much shorter than the time frame in which most natural pedogenic processes operate. Here the natural profile (S in Equation 1) predating the ‘‘new’’ modified profile (S2) can be considered the ‘‘new’’ pm, so that
Pouyat (1991) proposed that human influences necessitate the inclusion of a separate factor because humans, unlike other organisms, are purposeful manipulators of soils (Bidwell and Hole, 1965). Furthermore,human effects on soils occur on different spatio-temporal scales than those of other organisms,primarily because of the use of technology by humans. Technology has supported an exponential increase in human population growth and has increased the extent and magnitude of our disruption of the landscape (Ehrlich et al., 1976).The conceptual model of soil-forming factors was described by Dokuchaev in 1879 and Hilgard in1892 (Arnold, 1983). In 1941, Jenny proposed the factoral model of soil genesis as a athematicalexpression in which each factor acted independently of the others such that the manipulation of one factor does not affect another. Likewise, the anthropogenic factor can act independently of the other factors. For example, if a human-induced catastrophic event occurs in which the soil profile is disrupted, the human impact on that soil occurred independently of the other soil forming factors. In this case, however, the temporal scale of the human modification is much shorter than the time frame in which most natural pedogenic processes operate. Here the natural profile (S in Equation 1) predating the ‘‘new’’ modified profile (S2) can be considered the ‘‘new’’ pm, so that
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