B095-0014
Responses of Critical Zone Soil Processes to Climate: A Meta‐Analysis
Tuesday, 15 December 2020
Poster
Xi Zhang, Oregon State University, College of Earth, Ocean, and Atmospheric Sciences, Corvallis, United States, Sharon A Billings, Univ Kansas, Lawrence, KS, United States, Daniel Hirmas, University of California Riverside, Riverside, CA, United States, Attila Nemes, Norwegian Institute of Bioeconomy Research, Ås, Norway, Aaron N Koop, University of Kansas, Lawrence, KS, United States, Alejandro Cueva, University of California, Riverside, Riverside, CA, United States, Li Li, Pennsylvania State University Main Campus, Department of Civil and Environmental Engineering, University Park, PA, United States, Hang Wen, Pennsylvania State University, State College, PA, United States, Alejandro N Flores, Boise State University, Boise, ID, United States and Pamela Sullivan, Oregon State University, Corvallis, OR, United States
Abstract:
Soil, through which water and energy are exchanged between the Earth's spheres, is the heart of the critical zone. Pedogenic processes and the physical structure of soil and the surrounding pore space are mediated, in part, by climatological factors. Thus, a clear understanding of the feedbacks between soil processes and climate is essential for projecting future soil functioning via pedogenic and hydrologic modeling. Although the importance of climate in soil processes has long been recognized, its role in soil genesis and structure development is difficult to separate from other confounding factors. The recent emergence of large, broad-scale soil datasets provides an important opportunity to explore the influence of climate on pedogenic development and structural processes across different spatial scales. We examine the fundamental role of climate in the formation and associated structural properties of soil using continental-scale datasets with a focus on clay illuviation and pore-size distribution.
We selected soil data representing a wide range of climate regimes from the continental-scale Pedogenic and Environmental Dataset and Unsaturated Soil Hydraulic Database. The depth to the Bt horizon, depth to maximum clay content, and thickness of the argillic horizon were identified as soil morphological properties related to clay illuviation. All three response variables were correlated with climatological factors (i.e., mean annual precipitation, effective precipitation, ratio of evapotranspiration to precipitation, ratio of potential evapotranspiration to precipitation). We used soil water retention data to derive soil pore-size distribution and distinguish structural macropores from textural pores. The parameters of the fitted soil water retention curves, which describe pore-size distributions, were correlated with climatological factors such as precipitation. This work helps quantify the relationships between soil processes and climate, illuminates the linkage between pedogenic and structural processes, demonstrates that climate is an important predictor of soil formation and associated structural development, and provides a basis for better understanding the sensitivity of water fluxes, chemical weathering, and nutrient cycling in the soil to future climate scenarios.
