Browsing by Subject "GENESIS"

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Open Access
Game Changer in Soil Science. The Anthropocene in soil science and pedology.
(Journal of Plant Nutrition and Soil Science, 2020-02-01) Richter, DD
© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim The venerable science of pedology, initiated in the 19th century as the study of the natural factors of soil formation, is adapting to the demands of the Anthropocene, the geologic time during which planet Earth and its soils are transitioning from natural to human-natural systems. With vast areas of soils intensively managed, the future of pedology lies with a renewed science that can be called anthropedology that builds on the pedology of the past but proceeds from “human as outsider” to “human as insider.” In other words, the human in pedology must shift from being a soil-disturbing to soil-forming agent. Pedology is well prepared to respond to the challenges of the Anthropocene, given the decades of research on human-soil relations throughout human history and throughout the period of the Great Acceleration (Steffen et al., [76]). However, quantitative understanding of soil responses to the diversity of human forcings remains elementary and needs remedy.
Open Access
The Formation of Clay-Enriched Horizons by Lessivage
(Geophysical Research Letters, 2018-08-16) Calabrese, S; Richter, DD; Porporato, A
©2018. American Geophysical Union. All Rights Reserved. Soils with argillic horizons comprise more than 25% of the Earth's surface. Although their origin is still debated, lessivage is often invoked to explain them, but the long timescales involved hinder its direct experimental verification. We present a parsimonious model of clay transport, formulated for long timescales over which lessivage is modeled stochastically, complemented by detailed field observations. This probabilistic description allows us to predict the clay profile, the depth of the Bt horizon from the surface, and the mean clay residence time. The results are tested with field measurements at different locations in the Calhoun Critical Zone Observatory. Dimensional analysis unveils two dimensionless parameters governing lessivage dynamics, leading to a classification based on erosion rates and lessivage characteristics. We identify static and eluviated regimes, in which erosion or eluviation prevails, and an illuviated regime, in which the balance between lessivage and erosion brings about the formation of a Bt horizon.