Sanjita Gurau Master’s Thesis Defense, Tuesday, November 25, 2025 @ 10:00 am Central Time

COMMITTEE CHAIR: Dr. Ram Ray

TITLE: FIELD-SCALE EVALUATION OF ALGAL BIOFERTILIZER TO ENHANCE SOIL HEALTH, CARBON SEQUESTRATION, AND COTTON YIELD FOR SUSTAINABLE AGRICULTURE

ABSTRACT: The intensive use of synthetic fertilizers in cotton production has improved yields but has also contributed to soil degradation, nutrient imbalance, and greenhouse gas emissions. To promote sustainable nutrient management, this study evaluated the field-scale potential of algal biomass as a biofertilizer for enhancing soil health, carbon sequestration, and cotton productivity under southern U.S. agroecosystem conditions. The two-year experiment (2023-2024) was conducted at Prairie View A&M University’s Research Farm in Texas using a randomized complete block design. The first year (2023) established baseline data with four synthetic nitrogen fertilizer rates Control (no fertilizer), Double the recommended nitrogen rate, Recommended nitrogen rate and Half of the recommended nitrogen rate, while the second year (2024) examined six treatments Algae+NPK, Algae, NPK, Sterilized Algae+NPK, Sterilized Algae, and Control applied to 36 field plots. Soil physicochemical properties, greenhouse gas fluxes (CO2, CH4, N2O), and plant growth parameters were monitored using in-situ sensors, trace gas analyzers, and laboratory analyses (CHNS and ICP). Results revealed that algal biomass substantially improved soil moisture retention and moderated electrical conductivity compared to conventional NPK and control treatments, indicating enhanced soil structure and reduced salinity stress. The Algae and Algae+NPK treatments increased soil carbon and nitrogen content, stimulated root growth, and improved belowground biomass accumulation, suggesting potential for long-term carbon sequestration. Cotton yield in algae-treated plots was comparable to or higher than NPK plots, confirming that algal biomass can sustain productivity while reducing dependence on synthetic fertilizers. Greenhouse gas fluxes did not differ significantly across treatments; however, algal plots exhibited slightly lower N2O emissions and mild CH4 uptake, demonstrating potential environmental co-benefits. Overall, this research provides field-based evidence that algae-based biofertilizers enhance soil health, support crop productivity, and contribute to climate-smart agriculture. The study highlights algae as a promising biofertilizer for cotton systems, though further long-term studies are needed to address heavy metal content, optimize application rates, and evaluate large-scale feasibility.

Keywords: Algal biofertilizer; Soil health;  Cotton; Greenhouse gas; Carbon sequestration; Sustainable agriculture

Room Location: CARC Seminar RM # 015