Presenters-0720
From CSDMS
CSDMS 2026: Modeling Landscapes in Motion
Feedback between Soil Biogeochemistry and Landscape Evolution: Opportunities for the Two Mature Fields to Address Pressing Earth Surface Science Issues
Abstract
In soil-covered landscapes, the genesis, weathering, and erosion of soils are an integral part of both biogeochemical cycles and landscapes’ morphologic evolution. However, the intimate feedback between landscape biogeochemistry and morphology through soils has not been frequently described and predicted through mathematical models. Nonetheless, a growing number of critical earth science questions, which are central to understanding climate change, ecosystem dynamics, and agricultural sustainability, hinge on integrating the two aspects of soil-covered landscapes. Here, we present three studies that explicitly, quantitatively, and mechanistically consider the connections. The first case demonstrates how the modeling of soil erosion and soil production can contribute to re-interpreting radiocarbon data. Once physical movements of soil constituents – a topic of soil geomorphology – is incorporated into interpreting radiocarbon age – a topic of soil carbon - a new insight on the biological sensitivity of soil carbon decomposition is gained. The second ongoing study zooms into the feedback between soil carbon, bulk density, and soil faunal activities, illustrating their co-impacts on landscape morphology and hydrology. This example utilizes the data from the earthworm invasion transects in Minnesota sugar maple forests. Lastly, the significance of explicitly incorporating agricultural activities in geomorphic modeling of rugged but soil-mantled landscapes is acknowledged. Using our mapping exercise from the Upper Mississippi Valley, where its steep slopes and deep valleys sharply contrast with the surrounding landscapes in Minnesota, Wisconsin, Iowa, and Illinois and where smallholder farmers are concentrated, we show how agricultural land uses reflect geomorphic process domains determined by landscape morphology and associated soil properties. These examples stress that disciplines of soil biogeochemistry and geomorphology are mature enough to be quantitatively and mechanistically integrated and that such integration can help us better understand the pressing issues related to climate change and water resources and improve the relevance of earth surface science to the broader groups around the world.
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