Search

Brackish water stands as a promising alternative to mitigate freshwater scarcity in arid regions. However, its application poses potential threats to agricultural sustainability. There is a need to establish a clear understanding of the economic and ecological benefits. We conducted a two-year (2021-2022) field experiment to investigate the effects of four different irrigation water salinity levels on soil electrical conductivity, cotton yield, water use efficiency, CO 2 emissions, and carbon sequestration. The salinity levels were designated as CK (0.85 g L -1 ), S1 (3 g L -1 ), S2 (5 g L -1 ), and S3 (8 g L -1 ). Results indicated that using irrigation water with high salinity (≥5 g L -1 ) led to the accumulation of salt in the soil, and a decrease in plant biomass and seed cotton yield. Compared to CK, the S3 treatment decreased by 18.72 % and 20.10 % in the respective two years. Interestingly, using brackish water (3 L -1 and 5 g L -1 ) decreased the rate and cumulative CO 2 emissions, and increased the carbon emission efficiency and carbon sequestration by 0.098-0.094 kg kg -1 and 871-1859 kg ha -1 in 2021, 0.098-0.094 kg kg -1 and 617-1995 kg ha -1 in 2022, respectively. To comprehensively evaluate the tradeoff between economic and ecological benefits, we employed the TOPSIS method, and S1 was identified as the optimal irrigation salinity. Through fitting analysis, the most suitable irrigation salinity levels for 2021 and 2022 were determined as 3.52 g L -1 and 3.31 g L -1 , respectively. From the perspective of water conservation, salinity management, yield improvement, and reduction of CO 2 emissions, it is feasible to utilize brackish water for irrigation purposes, as long as the salinity does not exceed 3.52 g L -1 (first year) and 3.31 g L -1 (second year)., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)