Tim Bowles, Professor

Closed (1) Understanding on-farm soil health

Closed. This professor is continuing with Spring 2021 apprentices on this project; no new apprentices needed for Fall 2021.

Despite extensive efforts to measure on-farm soil conditions, the concept of soil health continues to be a murky concept across soil science, agriculture, and policy disciplines. However, soil health is critical to productive agriculture and long-term, whole-farm resilience. At present, most measurements of soil health on organic farms often involve observable or qualitative assessments, at best, and/or lack calibration to local climates. In addition, incorporation of farmer perceptions is also currently lacking. To address this gap, additional research on overall on-farm soil health metrics for farmers in regions with diverse microclimates like California is essential.

Our research will measure biophysical indicators of soil health on mixed-vegetable, diversified farms in Yolo County. We will complement this work with qualitative metrics, where we will determine farmer perceptions of soil health through semi-structured interviews. This study will further our understanding of the functional role of soil health on farms, incorporating existing farmer wisdom with quantified soil metrics.


Students will be asked to work on ongoing lab work for the project. Soil measurements will include nutrient cycling and microbial activity. This project is an excellent opportunity for students interested in fine-tuning experience with lab work.

Day-to-day supervisor for this project: Ansel Klein, Graduate Student

Qualifications: Interest in soil science, microbial ecology, and agroecology. Extreme precision and attention to detail. Interest in detail-oriented work. Previous lab experience is required.

Weekly Hours: 6-8 hrs

Related website: https://bowleslab.netlify.com/

Closed (2) Urban agroecology to build soil health and address food insecurity

Applications for fall 2021 are now closed for this project.

Our lab is currently investigating innovative soil management strategies tailored to urban agricultural systems, aimed at maximizing efficiency, addressing food insecurity, and enhancing climate resilience of agroecosystems. In partnership with the Berkeley Food Institute, we have joined a coalition of soil scientists, ecologists, city planners, and cooperative extension specialists to develop practices that will address concerns over soil health and soil contamination in the city.

One part of this work is a two-year experiment at Berkeley’s 0.25 ha research field, the Oxford Tract. We are comparing a novel no-till management system, combined with cover cropping, against conventional tillage methods typically used by production farmers.

With a focus on both soil ecology and the efficiency of crop production, we have tracked key metrics of soil health over the course of this long-term experiment, including total soil organic carbon (C) and nitrogen (N), microbial activity, water use efficiency, fungal community composition, crop drought response, and more.

In addition, our team has also taken sociological data on the impact of our small model farm. This includes interviews with urban farmers, food distributors, and consumers of food produced in urban environments. We have carefully tracked all the food from our farm to those who received it, all based on alternative economies and solidarity networks in the East Bay. By mapping these dynamics over a series of years, and speaking with those directly involved, we hope to understand the capacity of small farms to meet the needs of food insecure populations in urban areas.

All this work points towards an understanding of soil health, the dynamic properties of soil that support the production of food and fiber while providing key ecosystem services such as water filtration, carbon storage, and contaminant buffering. We are also deeply concerned with how the health of the soil supports healthy communities. This is where we engage with food justice; delivering free produce through our robust network of partner organizations to people in need. How can creating vibrant agroecosystems address food insecurity and the resilience of impacted urban communities?

The student who joins this project will have the opportunity to participate at multiple scales simultaneously. The student will be predominantly engaged in analyzing the rich data set that we have collected, and critically analyze the role of our model farm both ecologically and sociologically. The student will also learn basics of experimental design and help maintain field research plots (e.g planting and irrigation). Students will learn how to collect and analyze both ecological and sociological data, summarize results, and report key findings back to our research group. Students will have the opportunity to participate in UC Berkeley's robust local food system, and help to demonstrate how small farms meaningfully address food insecurity.

Day-to-day supervisor for this project: Coleman Rainey, Ph.D. candidate

Qualifications: • Have a background in ecology, environmental science, chemistry, biology, or related fields • Maintain a 3.0 GPA or higher • Understand basic soil ecology, and its intersection with biochemistry, mineralogy, microbiology, etc. • Be passionate/have experience in farming or gardening • Preferably have research experience in a laboratory/bench chemistry environment • Work independently and be able to summarize and communicate findings clearly

Weekly Hours: 3-5 hrs

Related website: https://bowleslab.netlify.com/