Assessment of Salinity Intrusion Risks on Agricultural Land Use Changes in Ben Tre Province, Mekong Delta (2014-2023)

Background and objective: Ben Tre Province in Vietnam’s Mekong Delta has been severely affected by salinity intrusionevents, notably in 2016 and 2020, leading to extensive agricultural and economic losses. This study aims to evaluate thespatial and temporal impacts of salinity intrusion on agricultural land use from 2014 to 2023. Using a modified DRASTICmodel, Normalized Difference Vegetation Index (NDVI), and Geographically Weighted Regression (GWR), the researchidentifies vulnerable areas and provides insights for sustainable land-use management. Methods: A modified DRASTIC model, integrating Electrical Conductivity (EC) as a key parameter, was employed to assesssalinity intrusion risks. NDVI values, derived from Landsat 8 imagery for 2014 and 2023, quantified changes in vegetationcover. The GWR model explored spatial heterogeneity in the relationship between salinity risk and agricultural land-usedynamics. Validation was conducted using 200 field samples across eight agricultural land-use (ALU) types, including rice,fruit trees, cash crops, coconuts, barren land, aquaculture and water surface. Results: Salinity intrusion significantly reduced areas of rice (-4,450 ha), fruit trees (-37,785 ha), and aquaculture (-8,226ha), while promoting the expansion of salinity-tolerant species such as coconuts (+7,635 ha) and mangroves (+51,757 ha). High-risk zones were concentrated in coastal districts, particularly Ba Tri and Thanh Phu. GWR analysis revealed substantialspatial variability, highlighting the resilience of salinity-tolerant crops adapted to saline conditions. Conclusion: This study demonstrates the critical impact of salinity intrusion on agricultural systems and emphasizes thenecessity of transitioning to salinity-resilient crops. By integrating spatial analysis and adaptive modeling, the findingsprovide actionable recommendations for mitigating salinity risks and enhancing the sustainability of ALU in Ben TreProvince.