Collaborative Research: Detecting Spatial Patterns of Dust Effects on Soils: Testing New Methodology in the Central Great Plains

University Of Wisconsin-Whitewater, Whitewater WI

Investigators

Abstract

This project will investigate the role of atmospheric dust deposition in creating regional spatial patterns of soil variation, using a study area in the central Great Plains. On the Great Plains, as in many other arid to subhumid landscapes, there is both geologic evidence and modern documentation of recurrent regional dust transport and deposition. During the Holocene, dust deposition at high rates produced distinct loess deposits in scattered localities in this region. More slowly deposited dust may have been incorporated into developing soil profiles over much larger areas. The key new element in this project is the focus on detecting regional spatial patterns indicative of dust transport, using a network of sampling sites across the central Great Plains. Dust deposition rate, grain size, and mineralogy vary systematically with distance from the source. These trends should be reflected in regional spatial patterns of soil morphology and mineralogy corresponding to "plumes" of Holocene dust dispersal from major sources. Multiple soil profiles will be sampled at each site to quantify local variability. From the regional sampling network, the investigators will select representative soils to use in more detailed investigations of the mineralogical and geochemical evidence for dust addition during soil development. This project will test methodology that can be much more broadly applied to a basic problem of soil science, in landscapes affected by recurrent dust production and deposition. Dust deposition is widely recognized as an important process in soil formation, but most previous studies have not focused on broad regional patterns of dust effects on soils. These spatial patterns are the key to incorporating dust effects into our understanding of important soil-related environmental issues. For example, the potential of soils to store organic carbon is an important issue in efforts to predict and mitigate human-induced changes in the global carbon cycle. Dust deposition may affect regional patterns of soil carbon storage potential because the added dust can change soil properties that strongly influence carbon storage. Because this project will sample a regional network of soils, the results will be directly applicable to mapping soil carbon storage potential over a large region. Results of this project will also help interpret buried soils that are important indicators of past climate change.