Agricultural drainage-induced Albeluvisol evolution: A source of deterministic chaos

Abstract

It is currently widely accepted that soil formation is not only deterministic, obeying the well-known soil-forming factor theory, but also chaotic, being highly sensitive to small variations in the initial conditions that persist and grow over time. However, the origins as well as the specific time-scales of such chaotic evolutions still need to be explored. In this paper, the morphological degradation in Albeluvisols after 18years of agricultural subsurface drainage was quantified using image analysis in combination with mass balance calculations on a high-spatial-resolution soil sequence sampled perpendicularly to a drain line. Soil changes were found to i) vary as a result of complex interactions between the human-induced perturbations of the soil system and the prevailing environmental factors such as local topography and ii) result from a positive feedback loop between the soil moisture, soil water flows and mass transport. Human-induced perturbations of soil system are highly sensitive to the initial conditions and induce divergent soil changes over time and may be a non-negligible source of deterministic chaos. Finally, the significant material losses quantified on time scales as short as two decades suggested that human-induced perturbations of the soil system may be an interesting way to study the time-scales for such chaotic evolutions.