Integrated geospatial and hydrological approach for modeling and forecasting to detect crop water stress in Laos

Climate change impact a global threat as it exacerbates severe weather events and droughts, affecting food and water security. This study examines how rainfall, humidity, crop water losses and crop water stress index (CWSI) are changing in Laos from 2020 to 2022, focusing on trends caused by the monsoon and how droughts affect agriculture. Rainfall records indicate a delayed onset of the monsoon, with 55–60% of the northern highlands receiving 1–10 mm at the start of the season, while the southern lowlands receive over 30 mm. In the main monsoon season, 60–70% of Laos receives more than 50 mm of rainfall; however, the northern parts receive less rainfall due to topographical obstacles. Relative humidity varies between 40–60% in winter and 50–80% in spring, with greater fluctuations in 2022. Evapotranspiration is minimal (2–6 mm) in 60–70% of the region during the dry seasons, while it increases in the southern areas with monsoon rainfall. The CWSI reaches a maximum value of 25% heavy load in May, corresponding with reduced soil moisture levels (~190–200 mm) and negative SMDI values. The research points to the importance of integrated drought monitoring for agricultural resilience in Laos.