Date of Award

Fall 12-16-2017

Semester of Degree

December

Document Type

Open Access Dissertation

Degree Name

Ph.D. in Environmental Science

Department

Environmental Science, Division of

Major Professor

Stewart Diemont

Steering Committee Member

Russell Briggs

Steering Committee Member

Robin Kimmerer

Steering Committee Member

Theresa Selfa

Abstract

This research was conducted in the tropical mountainous area in the northeast of Oaxaca, Mexico (Sierra Norte). This area is inhabited by the Zapotec indigenous people whose livelihoods rely upon traditional agriculture. The Zapotec farmers’ main agricultural system is the milpa, an intercropping of primarily corn and beans; shaded coffee; and sugar cane. Trees are also part of the cropping systems and provide shade as in shaded coffee, function as barriers between land uses, or are used to shift from annual cropping to perennial shade coffee. This research demonstrates that these various land uses are part of a traditionally designed agroforestry system that provide ecosystem services such as carbon sequestration, and soil fertility. The first approach to study this system was an emergy evaluation of the Zapotec traditional education system (TEK-education). More specifically, I looked at the energy inputs from renewable and non-renewable resources that supports this knowledge system. Second, I compared soil fertility, carbon and nitrogen concentrations, among land-uses within the Zapotec agroforestry. For shaded coffee, I determined carbon sequestration in the standing biomass and carbon inputs from litterfall from the leguminous species Inga spp. Results from these lines of research indicated that TEK education systems have similar emergy transformity values, and lower environmental impact than conventional systems. Soil organic carbon and nitrogen concentrations were higher in secondary forest and were not statistically different among land uses under cropping, thus providing evidence of the conservation of soil nutrients among land uses. I found that milpa cropping had an acidic pH, and sugar cane had the lowest soil organic carbon and nitrogen. Hence, I developed an experiment to test the use of mulch derived from Inga vera Wild. and the organic fertilizer Bio-orgamin to increase soil pH, exchangeable cations, and milpa yields. This treatment showed promise for increasing pH and exchangeable cations, and to increase biomass in milpa. Finally, I included a chapter on performance ethnography, reflecting on my own experiences while engaging in research within the Zapotec community to which I belong.

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