Term of Award

Fall 2015

Degree Name

Master of Science in Biology (M.S.)

Document Type and Release Option

Thesis (restricted to Georgia Southern)

Copyright Statement / License for Reuse

Digital Commons@Georgia Southern License

Department

Department of Biology

Committee Chair

Stephen Vives

Committee Member 1

Ray Chandler

Committee Member 2

Lissa Leege

Committee Member 3

David Kreller

Abstract

Global climate change is the biggest environmental challenge of this century. Potential climate change adaptation and mitigation strategies are to replace fossil fuels with bioenergy sources that have near-zero net CO2 emission and to utilize practices that promote carbon sequestration. This study assesses the soil carbon sequestration and bioenergy production potentials of switchgrass (Panicum virgatum) and longleaf pine (Pinus palustris) agroforestry systems in the southeastern coastal plain. Switchgrass has high biomass yield potential under low nutritional and management requirements and longleaf pine is a common native tree species in the southeastern coastal plain. The primary goal of this study was to establish a first-year rotation of switchgrass amongst three fertilizer treatments across four stands of longleaf pine to assess biomass production, carbon sequestration, and isotopic identification of soil carbon sources (C3 vs C­4 plants). The three fertilizer treatments were no fertilizer, inorganic, and organic. The N:P:K ratio for both inorganic and organic fertilizers were 11:2:2. Inorganic fertilizer resulted highest yield of switchgrass under the agroforestry systems compared to the monoculture stands of switchgrass. The comparison between before and after study soil carbon stocking did not show any significant carbon sequestration in the study plots. The isotopic analysis revealed that the predominant carbon source came from C3 plant (pine) contributions, probably a result of pine timber practices that were established at the field sites for many years prior to the study. The presence of longleaf pine artificial stands may have favored the establishment of switchgrass when compared to monoculture planting. Since no carbon was sequestered within the one year timeframe, an extended study needs to be conducted for further insight on how much carbon can be sequestered over multiple seasons of implementing this practice.

Research Data and Supplementary Material

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