COMMITTEE CHAIR: Dr. Ram Ray

TITLE: CARBON SEQUESTRATION AND GREENHOUSE GAS EMISSION DYNAMICS OF FORAGE SORGHUM CULTIVARS IN SOUTHERN TEXAS

ABSTRACT: Carbon sequestration is an important strategy that removes carbon dioxide from the atmosphere and stores it in soil and vegetation. The study aimed to evaluate carbon sequestration, carbon emission in three different forage sorghum varieties: annual (Sugar Graze Ultra), perennial seeded sorghum (PSH20TX01), and perennial rhizomatous sorghum (PSH09TX15). The experiment was conducted from June 2024 to September 2025 at Prairie View A&M University’s research farm, with each sorghum variety allocated to nine plots. Three different nutrient treatments were applied to the sorghum plots (recommended, half, and double nutrient application rates). Each plot was irrigated using a drip irrigation system, which provided water directly to the plants. Soil carbon emissions were measured using Soil CO2 Flux Chambers and a trace gas analyzer in each plot on a weekly basis. Soil sensors measuring soil moisture, temperature, and salinity were installed on each plot. Both disturbed and undisturbed soil samples were collected from depths of 0-15 cm (surface) and 15-45 cm (subsurface) before planting and after harvesting. Soil bulk density, porosity, and organic matter content were analyzed to understand the dynamics of soil carbon over time. Above-ground and below-ground biomass were collected within 2ft × 2ft area in each plot at the end of the season, and fresh and dry weights were measured. Statistical analysis using two-way ANOVA in R statistical software revealed significant differences in biomass among sorghum varieties. The annual sorghum variety exhibited a significantly higher aboveground biomass, while the perennial rhizomatous sorghum variety had significantly higher belowground biomass. Although the soil organic carbon content did not show any statistical difference over time, the soil bulk density was decreased across all three varieties. Lower soil carbon emissions were observed in PSH09TX15 than in others. This study offers new insights into the carbon sequestration capabilities of forage sorghum cultivars, thereby contributing to climate change mitigation efforts.

Keywords: Soil organic carbon; Forage sorghum; Agriculture; Flux Chambers; Carbon sequestration

Room Location: CARC Seminar RM # 015