Research

Fundamental questions on soil genesis

Soils move. Energy transports through soils. The physical movement of soil materials through erosion and disturbance and heat transport through soils contribute to shaping soil biogeochemistry. We develop physics-based hypotheses and models and empirically test them so that we can learn more about how soils are formed in the real world.

Soil formation in the Anthropocene

Humans have been reshaping soils on a global scale, both knowingly and unknowingly. We are particularly concerned about biological invasions and the effects they have on soils. For example, we seek to understand how human-assisted transport and the introduction of earthworms quickly change the flow of materials and energy through soils, which has huge effects on biodiversity and the functioning of ecosystems.

Critical Zone Science for mountain smallholder farmers

Smallholder farmers produce the majority of food in developing countries, accounting for 20-34% of the global food supply. Many of them overlap with the 1.1 billion people who live on steep hills and mountains. We are working to advance our fundamental understanding of the mountain critical zone, a vertical zone of the earth between the tree canopy and groundwater, as a basis for the livelihoods of the world's smallholders.

New interdisciplinarity of environmental science

In the time of climate change and the Anthropocene, environmental scientists bear a great deal of responsibility. We want to collaborate with filmmakers, storytellers, artists, humanities scholars, and theologians who share a sense of urgency about their own responsibilities.

Teaching

Professor Yoo's mission as an instructor is to present the relevant materials as a body of evolving knowledge as holistically as possible. He is currently teaching three classes: a graduate course on soil formation (LAAS 5515), an orientation course for all new graduate students in Land and Atmospheric Science (LAAS 5050), and an online course for undergraduates on the interactions between land and people across diverse world cultures (ESPM 3051).  The course goals, the most recent course syllabus, and students' teaching evaluations are available on the teaching page.

Professor Yoo is a big fan of blackboards and chalk, and he believes that we all learn best in mutually respectful and supportive environments. Professor Yoo is also committed to improving the quality of online teaching because the format allows for broader access to education. For example, more than half of the students in the fully online ESPM 3051 (Lands and Humans in World Cultures) are from outside the College of Food, Agriculture, and Natural Resources Sciences.

Outreach

Our mission is to share the joy of learning about soils as a gift. It is our job to tell people about the important issues with the land. We have worked with international filmmakers as well as local media, and our work has been communicated to the general public through venues like the Minnesota State Fair. In the coming years, we will focus on creating research-, teaching-, and outreach-related collaborations with groups that have rarely been partners of soil scientists. Those communities include, for example, indigenous rights activists, filmmakers, and faith communities.