Soil flooding increases greenhouse gas fluxes

Soil flooding significantly impacts livelihood, agriculture, and the environment, affecting soil health. This study investigated the effects of flooding, flooding duration, and water source (seawater vs. freshwater) on greenhouse gas fluxes from two predominant soil types in South Florida—Krome and Biscayne. Experiments were conducted by flooding Krome and Biscayne soils with fresh and seawater, and greenhouse gas samples were collected using PVC chambers on the 1 st , 7 th , 14 th , and 28 th days of flooding. Samples were analyzed for soil carbon dioxide (CO 2 ), nitrous oxide (N 2 O), and methane (CH 4 ) fluxes using a gas chromatograph. Results confirmed that CO 2 and N 2 O fluxes exhibited a distinct pattern, peaking one day after flooding and sharply decreasing with the progression of flooding. Soil type, flooding duration, and water source were critical factors modulating CO 2 and N 2 O fluxes, but CH 4 fluxes were consistently below the detection limit. Biscayne soil had the highest CO 2 and N 2 O fluxes under seawater and freshwater flooding compared to Krome. These findings underscore the critical role of the initial flooding phase in driving greenhouse gas emissions, emphasizing the need for targeted mitigation strategies. • CO 2 and NO 2 fluxes were affected by soil, water type, and flooding duration • The first day of flooding resulted in peak soil CO 2 and NO 2 fluxes. • The highest CO 2 and NO 2 fluxes were recorded from Biscayne soil.