Nov 8, 2013, 11:30am - 12:25pm
HCS Seminar
HCS Seminar
Dr. Jennifer Blesh, Assistant Professor, University of Michigan, Department of Ecology and Evolutionary Biology.
Agroecosystem management and nitrogen balance on grain farms in the Midwest
ABSTRACT: Human alteration of the global nitrogen (N) cycle, particularly through agricultural production, has led to persistent environmental consequences. For example, soluble N forms leach to surface waters and are transported to coastal marine ecosystems causing eutrophication and hypoxia. This seminar will explore how applying ecological theory to N management can tighten agroecosystem N cycling, using research on farms in the upper Mississippi River Basin (MRB) as a case study. Nitrate losses from grain farms in this region are a primary contributor to the annual hypoxic zone in the Gulf of Mexico. Nitrogen mass balances were constructed for a range of farm management types—from corn-soybean rotations to diversified farms that rely on legume nitrogen fixation as a primary N source—in four states in the upper MRB: Iowa, Minnesota, Ohio and Wisconsin. The N balance approach combined data from farmer interviews with analysis of grain and legume samples, and measurements of legume N fixation. Practices that increase carbon sinks for inorganic N, and support the rhizosphere processes that supply N through the soil N cycle, can reduce surplus N additions. This research also addressed how a subset of farmers had transitioned to practices that the N balance study indicated have the greatest potential for reducing N loading to the Gulf of Mexico, focusing on the resources and strategies that farmers mobilized to develop opportunities for innovation.
Host: Dr. Kristin Mercer
mercer.97@osu.edu
mercer.97@osu.edu
11:30 AM - 12:15 PM
244 Kottman Hall (Columbus)
video-linked to
121 Fisher Auditorium (Wooster)