Date of Award

12-2025

Document Type

Thesis

Degree Name

Master of Science

Department

Natural Resources and Environmental Sciences

Abstract

Carbon sequestration is one of the major strategies for removing atmospheric carbon dioxide and fixing it in the soil and plants. The research study focused on the carbon sequestration and greenhouse gas dynamics of three different forage sorghum cultivars: Sugar Graze Ultra (annual), PSH20TX01 (perennial seeded), and PSH09TX15 (perennial rhizomes), in Southern Texas, where each cultivar had nine plots. The field study was conducted over two growing seasons, in 2024 and 2025, at the Prairie View A&M University research farm. Three different fertilizer rates, recommended, half-recommended, and zero fertilizer rates, were applied. Soil greenhouse gas emissions were measured using a trace gas analyzer and a flux chamber in each plot on a weekly basis throughout the seasons. Both soil-disturbed and soil-intact core samples were collected from depths of 0-15 cm and 15-45 cm before and after planting season 1, and after harvesting season 2. Above-ground and below-ground biomass were collected from a 2 ft × 2ft area at each end of the season. Soil bulk density, total carbon percentage, soil pH, and soil electrical conductivity were analyzed. Soil carbon stock, total plant carbon stock, total below-ground carbon stock, and total ecosystem carbon stock were calculated using the biomass and soil data. Statistical analysis using ANOVA revealed that the bulk density in the soils of PSH09TX15 was significantly lower than that of the soils in the Sugar Graze Ultra at both depths at the end of season 2. Although there was no significant difference in soil total carbon among varieties in season 2 in the surface, subsurface total carbon was significantly increased in the PSH20TX01. Total ecosystem carbon storage was highest in the Sugar Graze Ultra cropping system (18.98 Mg C/ha). However, PSH09TX15 showed the highest below-ground carbon stock (11.01 Mg C/ha), which directly influenced the long-term soil carbon sequestration. Lower CO2 emissions were recorded in the soils of PSH09TX15. The research provides insights into the carbon sequestration capabilities of three forage sorghum varieties, thereby highlighting their potential to mitigate climate change.

Index Terms: Carbon sequestration, forage sorghum, greenhouse gases, soil CO2 flux chambers, total ecosystem carbon stock.

Committee Chair/Advisor

Ram Ray

Committee Member

Gebrekidan Tefera

Committee Member

Richard Griffin

Rights

© 2021 Prairie View A & M University

Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

Date of Digitization

01/20/2026

Contributing Institution

J. B . Coleman Library

City of Publication

Prairie View

MIME Type

Application/PDF

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