Ryan Stewart

Assistant Professor


Ph.D. Water Resources Engineering, Oregon State University, Corvallis, OR, 2013

M.S. Water Resources Engineering, Oregon State University, Corvallis, OR, 2010

B.S. Mechanical Engineering, Cal Poly, San Luis Obispo, CA, 2002


2013-Present Assistant Professor, Crop & Soil Environmental Science, Virginia Tech

2013 Post-Doctoral Research Scholar, Oregon State University, Corvallis, OR

2008-2013 Graduate Research Assistant, Oregon State University, Corvallis, OR

2006-2008 Peace Corps Volunteer – Basic Sanitation, Bolivia

2004-2006 Specialist – Oak Lodge Sanitary District, Milwaukee, OR

Link to curriculum vita

Courses Taught

I teach several upper-division and graduate courses focused on environmental, hydrological and soil processes.  These courses include:
ENSC 3614 (CSES 3164): Soil Physical and Hydrological Properties
Soil physical and mechanical properties and the physical processes controlling soil water retention and flow in agronomic and natural settings. Grain size distribution, weight-volume relationships, specific surface, electrical charge density, consistency, stress, compaction, rainfall runoff, water retention, steady/non-steady water flow in saturated/unsaturated soil, infiltration, bare soil evaporation, and soil water balance.
ENSC 3634 (CSES 3634): Physics of Pollution
Physical processes that control the fate of pollutants in our land, air, and water resources. Types and sources of pollutants, physical processes in the soil-water-atmosphere continuum controlling the dispersion and deposition of pollutants, the movement of pollutants, including radionuclides, by surface and subsurface water flow in soils, and physics of disturbed soils.
FREC 5144: Hillslope and Watershed Hydrology (Co-Instructor)
Physical concepts of hydrological processes that affect age, origin, and flowpaths of water from hillslope to watershed scales. Analysis of current and historical research methods. Hydrological science as an interdisciplinary topic. Pre: Graduate standing (3H, 3C)

Program Focus

The Critical Zone Lab at Virginia Tech focuses on understanding and quantifying interactions between water, soil, and plant communities. This includes a combination of field work, laboratory analysis, and development of modeling frameworks. We foster active collaboration across disciplines, working on topics which span ecology, engineering, agriculture, and urban systems.
Current and Future Research
Management Effects on Soil Health
•    Generating quantitative data focused on the effects of tillage practices and inclusion of multi-species cover crop mixtures on:
•    physical properties (e.g., water holding capacity, hydraulic conductivity)
•    biological indicators (e.g., microbial biomass),
•    nutrient and water cycling
Environmental fate and transport of solutes, including
•    Emerging contaminants, such as neonicotinoid pesticides and antibiotics
•    Nutrients
•    Stable water isotopes
•    Consideration of preferential flow processes
Fire effects on soil and water quality
•    Changes in soil condition (e.g., water repellency, erosion) post-wildfire
•    Prescribed fire effects on water quality and quantity
Incidence and prediction of dynamic soil hydraulic properties, including
•    Infiltration studies
•    Post-mining soil reclamation and recovery
•    Shrink-swell clay soils
•    Urban hydrology and soils
•    Effects on greenhouse gas emissions/exchange

Role of Graduate Students
Graduate school is a time to develop skills which will enable students to achieve future success.  In addition to the knowledge gained from coursework and research, students will improve their abilities in critical thinking, scientific reasoning, reading comprehension, and effective writing and presenting.  As an advisor, I strive to maintain a positive scholastic environment, and work to promote each individual student’s growth and success.
Graduate students are vital contributors to the overall direction and vigor of the Critical Zone Research group.  I am always looking for motivated and hard-working graduate students to join the research group and help advance the understanding of critical zone processes. I accept graduate students at both the M.S. and Ph.D. levels, and do my best to work with students in finding the best match between their individual interests and the activities and direction of the overall research group.

Undergraduate Research Opportunities
Active participation in a research group is one of the most rewarding experiences a student can have during their undergraduate education. Performing undergraduate research allows students the chance to apply their classroom knowledge and to develop new and exciting skills and connections.  Undergraduate students with research experience generally are more competitive applicants for positions in both grad school and in industry.  Therefore, I am always developing research opportunities for undergraduate students that are interesting and worthwhile.   Please contact me to discuss undergraduate research opportunities in greater detail.


Ryan Stewart