The Office of the Vice President for Research and Innovation recognizes Ryan Stewart, an assistant professor of crop and soil environmental sciences in the College of Agriculture and Life Sciences, who works at the “critical zone” between water, soil, and plant communities.
His program at the Critical Zone Research Lab fosters collaboration across disciplines, with diverse researchers working on topics that span ecology, engineering, agriculture, and urban systems. The effort involves field work, laboratory analysis, and development of modeling frameworks to focus on quantifying and scaling interactions between water, soil, and plant communities.
Stewart is involved in a variety of research projects. Among them, he is interested in the effects of land-use changes on the movement, distribution, and quality of water, especially in areas where forests are being established or re-established.
Another research interest includes study of soil-water interactions in shrink-swell clay soils, including the changing hydraulic conductivity of soil matrix due to swelling and shrinking, the time-dependence of swelling, threshold behaviors in runoff and infiltration, and scaling of hydrologic processes.
In other areas, Stewart characterizes structural pathways caused by plants and soil aggregation by describing nutrient transport and preferential flow using parsimonious models, development of new soil parameters to use in infiltration and runoff modeling, and numerical modeling to better understand processes.
His lab also works to develop novel instruments and methods, including a new “resonating” rain gauge, instruments to monitor soil crack swelling dynamics, a new device to measure plot-scale runoff, and accelerometers to monitor environmental processes.
Stewart received his doctoral and master’s degrees in water resources engineering from Oregon State University and a bachelor’s degree in mechanical engineering from Cal Poly. Previously Stewart served in the Peace Corps as a basic sanitation volunteer in Huacareta, Bolivia.