BIOTURBATION BY BADGERS AND RODENTS IN PRODUCING POLYGENETIC AND POLYTEMPORAL DESERT SOIL BIOMANTLES: SOIL FORMATION, OR SOIL EVOLUTION?

Badgers are aggressive, powerful, deep-burrowing bioturbators that in western North America regularly penetrate and destroy calcic and petrocalcic horizons. They bioturbate for denning and predation purposes, with rodents being their dominant prey species. Their role in producing deep biomantles is confirmed by recent studies of soils and landscapes of the Tularosa Basin and adjacent mesa lands of south-central New Mexico. Here, owing to their deep and powerful burrowing propensities, Badgers regularly reset the pedogenic clocks of desert soils on both the large and small scale (from pedon to polypedon). In fact, few if any segments of this landscape have escaped their disturbance impacts, nor impacts of their rodent prey. Insofar as each burrowing episode is but a moment in geogenic-pedogenic time, the desert landscape is comprised of an almost infinite number of discrete geogenic-pedogenic disturbance time units. In other words, the soils and biomantles of this region –- and probably other desert regions -- are, in a literal sense, polygenetic and polytemporal. Our historic geogenetic-pedogenetic formation models -- for example the five factors (clorpt) model -- do not easily accommodate such highly variable genetic-temporal disturbance realities. But they cannot be ignored. Do we call such wholesale disturbance processes soil formation, or soil evolution? The answer -- soil evolution, and these realities, have broad implications for soil genesis theory, archaeological theory, and for landscape evolution theory.