Abstract
Salinity intrusion is a pressing issue in the coastal areas worldwide. It affects the natural environment and causes massive economic loss due to its impacts on the agricultural productivity and food safety. Here, we assessed the salinity intrusion in the Tra Vinh Province, in the Mekong Delta of Vietnam. Landsat 8 OLI image was utilized to derive indices for soil salinity estimate including the single bands, Vegetation Soil Salinity Index (VSSI), Soil Adjusted Vegetation Index (SAVI), Normalized Difference Vegetation Index (NDVI), and Normalized Difference Salinity Index (NDSI). Statistical analysis between the electrical conductivity (EC1:5, dS/m) and the environmental indices derived from Landsat 8 OLI image was performed. Results indicated that spectral values of near-infrared (NIR) band and VSSI were better correlated with EC1:5 (r2 = 0.8 and r2 = 0.7, respectively) than the other indices. Comparative results show that soil salinity derived from Landsat 8 was consistent with in situ data with coefficient of determination, R2 = 0.89 and RMSE = 0.96 dS/m for NIR band and R2 = 0.77 and RMSE = 1.27 dS/m for VSSI index. Findings of this study demonstrate that Landsat 8 OLI images reveal a high potential for spatiotemporally monitoring the magnitude of soil salinity at the top soil layer. Outcomes of this study are useful for agricultural activities, planners, and farmers by mapping the soil salinity contamination for better selection of accomodating crop types to reduce economical loss in the context of climate change. Our proposed method that estimates soil salinity using satellite-derived variables can be potentially useful as a fast-approach to detect the soil salinity in the other regions with low cost and considerable accuracy.
Highlights
Salinity intrusion affects agricultural activities in many parts of the world (Suarez 1989; Shammi et al 2019). It has become a pressing issue in the Mekong Delta of Vietnam, which has been ranked among top five countries most likely to be affected by climate change coupled with sea level rise
In Vietnam, according to recent report of Directorate of Water Resources (DWR)Ministry of Agriculture and Rural Development (MARD), the discharge of water in the upstream of the Mekong River was reduced to 900 m3/s
It is found that the values of NIR band and Vegetation Soil Salinity Index (VSSI) indices are highly correlated with EC1:5 with coefficient of determinations 0.89 and 0.77, respectively, with corresponding lowest gradient values of 0.38 and 0.28, respectively
Summary
Salinity intrusion affects agricultural activities in many parts of the world (Suarez 1989; Shammi et al 2019). It has become a pressing issue in the Mekong Delta of Vietnam, which has been ranked among top five countries most likely to be affected by climate change coupled with sea level rise. Salinity intrusion occurs when salts are dissolved in water and accumulated in the soil at a level that affects agricultural production, environment, and economics. Salinity affects the metabolism of soil organisms and reduces the productivity of land. According to the report of DWR-MARD in Tra Vinh Province, in the dry season in 2016, 12,346 ha of rice were damaged due to the impact of drought and salinity intrusion, mainly in the Tra Cu, Cau Ngang, Tieu Can, Chau Thanh, and Duyen Hai districts and Tra Vinh City (CGIAR 2016) Provincial Report of Tra Vinh, 2011-2015
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
