Qi Wei
Hohai University, China
Title: Short-term response of soil N2O and CO2 emissions and their global warming potentials to irrigation salinity
Biography
Biography: Qi Wei
Abstract
Irrigation of brackish water (2-5 g L-1) instead of fresh water, modify soil microbial activities such as carbon and nitrogen cycle, and thus affect soil emissions of nitrous oxide (N2O) and carbon dioxide (CO2). However, the effects of irrigation salinity on global warming potentials (GWPs) caused by N2O and CO2 emissions are rarely investigated. Pot experiments with three irrigation salinity levels (2, 5 and 8 g L-1) were designed to study the responses of GWPs and the contribution of N2O and CO2 to various salinity levels. Results indicated that soil CO2 flux reduced with the increase of irrigation salinity and was obviously lower than that from fresh water irrigated soil (CK). By comparison, for N2O, 2 and 8 g L-1 saline water decreased the cumulative fluxes by 22.6% and 39.6% compare to CK (p<0.05), respectively, whereas 5 g L-1 saline water enhanced it by 87.7%. Overall, the cumulative GWPs of N2O and CO2 from irrigated soils using saline water (2-8 g L-1) were 3.2%-51.1% lower than that from CK, with the relative change to CK at 2 g L-1 salinity level significantly higher than those at 5 g L-1 salinity level. These results suggested that the degree to which soil Ec affected soil microbial processes might vary significantly among irrigation salinity ranges. Reducing the salinity of irrigated brackish water can mitigate soil GHGs and provides a potential strategy for solving water resources scarcity and reducing soil salt accumulation.