My research group conducts studies of soil nutrient cycling processes in agroecosystems at scales ranging from the rhizosphere to farm and watershed scales. We investigate mechanisms within the plant-soil-microbial continuum that control ecosystem processes such as energy flows and nutrient cycling. Current research projects are focused on achieving a better understanding of the biotic and abiotic mechanisms regulating linkages between carbon and nitrogen cycles, with particular emphasis on the following processes: 1) symbiotic biological N-fixation, 2) decomposition and mineralization and 3) microbially-mediated N transformations such as nitrification, denitrification. Our work is also geared toward the development of management practices that improve soil quality while optimizing carbon and nitrogen cycling in intensive horticultural systems. Most of our research involves some degree of interdisciplinary collaboration. We are currently working with colleagues from molecular microbial ecology, resource economics, environmental sociology, biogeochemical modeling and weed ecology.

The graduate and undergraduate courses I teach integrate ecological and agricultural knowledge. My over-arching goal in teaching and mentoring students is to contribute to the development of scientists who will be equipped to address the global challenges we face in agriculture and environmental management. In my classes we engage in participatory, independent and collaborative learning and work to improve key life skills including critical and synthetic thinking, verbal and written communication. Graduate seminars that I have offered include 1) Decomposition, 2) Sustainability: Ethical, socioeconomic and biophysical dimensions, 3) Agroecosystems: Research and design.