Date of Graduation

5-2026

Document Type

Thesis

Degree Name

Master of Science in Crop, Soil & Environmental Sciences (MS)

Degree Level

Graduate

Department

Crop, Soil & Environmental Sciences

Advisor/Mentor

Daniels, Mike

Committee Member

Greub, Kelsey

Second Committee Member

Fernandes, Samuel

Third Committee Member

Roberts, Trenton

Keywords

Conservation Agriculture; Greenhouse Gases

Abstract

The slow degradation of natural resources has resulted in the focus of agriculture shifting towards conservation practices, such as reduced/no-tillage, cover crops (CC), and organic amendments (i.e., biochar), that conserve and improve natural resource quality. The objectives of this thesis were to i) quantify the impacts of biochar rate (i.e., 0, 2000, and 4000 kg ha-1) and ii) the combination of CC and tillage practice on carbon dioxide (CO¬2), methane (CH4), and nitrous oxide (N2O) fluxes, growing-season-long emissions, global warming potential (GWP), soil properties, and plant response from a minimally tilled cotton (Gossypium hirsutum)-corn (Zea mays) rotation and a soybean (Glycine max)-corn rotation over the 2024 and 2025 growing seasons on a silt-loam soil in southeast Arkansas. Among biochar rates, no differences in season-long GHG emissions were reported in either growing season. However, averaged over time, 2024 CO2 fluxes were 649 and 637 mg m-2 hr-1 from the 2000 and 4000 kg ha-1 biochar treatments, which did not differ, and were greater (P < 0.01) than the 0 kg ha-1 biochar treatment (558 mg m-2 hr-1). Nitrous oxide fluxes during the 2025 corn growing season were greatest (P < 0.05) from the 4000 kg ha-1 treatment (0.12 mg m-2 hr-1), lowest from the 2000 kg ha-1 treatment (0.07 mg m-2 hr-1), and the control (0.09 mg m-2 hr-1) was similar to both biochar rates. Annual and two-year cumulative emissions and GWP from the cotton-corn rotation in the biochar study did not differ (P > 0.05) among biochar rates. In the CC and tillage practice study, GWP from the 2025 corn growing season was 16176 and 17025 kg CO2 equivalents ha-1 from the conventional and conservation field treatments, which did not differ. Despite the lack of emissions and GWP differences, CO2, CH4 and N2O flux differences occurred at times between field treatments (P < 0.01). This study contributes to a wider understanding of how implementing conservation practices may impact agroecosystems by evaluating the properties of GHGs, soil, and plants in side-by-side comparisons of conservation and conventional agricultural practices to pave a path for long-term sustainability of natural resources in Arkansas.

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