Date of Award

Winter 2018

Project Type

Dissertation

Program or Major

Natural Resources and Environmental Studies

Degree Name

Doctor of Philosophy

First Advisor

John D Aber

Second Advisor

Serita D Frey

Third Advisor

Kevin H Gardner

Abstract

Nitrogen management presents a unique dilemma: We must use nitrogen to grow our food and sustain life on earth, but excess reactive nitrogen that accumulates in the environment contributes to a cascade of negative impacts to human and ecosystem health. Addressing this nitrogen challenge will require a suite of solutions. This dissertation presents and explores three nitrogen management strategies: 1) The first ever integrated carbon and nitrogen footprint tool for campus sustainability management; 2) Exporting compost to improve a farm’s nitrogen efficiency; and 3) Methods for reducing gas emissions from aerated static pile heat recovery composting.

Nitrogen footprint tools connect our everyday choices with the associated nitrogen pollution to the environment. The campus-level nitrogen footprint tool has been particularly successful at both communicating the nitrogen story and encouraging real change with nitrogen footprint reduction goals. However, it is important to assess environmental impacts together to identify management strategies and avoid trade-offs. In this paper, the development and methodology behind the first ever integrated carbon and nitrogen footprint tool for campuses is presented. Comparisons of campus carbon and nitrogen footprints show that the footprints correlate strongly, and scenario analyses indicate benefits to both footprints from a range of management strategies. Integrating the carbon and nitrogen footprints into a single tool for campuses facilitates more comprehensive and integrated management of campus sustainability.

Food production is a significant source of nitrogen pollution, and new and improved farm nitrogen management practices are necessary to reduce nitrogen losses. In this study, aerated static pile heat recovery composting is considered as a nitrogen management strategy. To assess its potential, the nitrogen budget of an organic dairy farm was first assessed, where it was found that organic practices led to the cycling of substantially more nitrogen on the farm property than was imported or exported. Some of the potential farm nitrogen loss pathways were characterized, including gas emissions from the compost facility (ammonia, carbon dioxide, methane), but future research should characterize other nitrogen loss pathways to assess the balance between storage and environmental loss. Management strategies for reducing greenhouse gas and ammonia emissions from the compost facility were identified. Scenario analysis found that exporting finished compost was a viable strategy for improving the farm’s nitrogen use efficiency as long as enough nitrogen is retained on-site to support crop production.

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