One of the largest concentrations of acid sulfate soils in the world is found in the Vietnam Mekong River Delta, a large low-lying river plain scarcely above sea level, covering 1.6 million ha (4.0 ac; figure 1) (van Mensvoort 1996; Vietnam Ministry of Agriculture 1978; Huu et al. 2022). Acid sulfate soils have high concentrations of aluminum (Al), sulfates (SO4 2–), and iron (Fe), and when drained produce sulfuric acid (H2SO4) that reduces soil pH below 4 (van Mensvoort 1996; Huu et al. 2022). These metals accumulate in the topsoil during the tropical dry season and are toxic to plant root growth and development and suppress yields making them some of the most difficult soils in which to grow agricultural crops. Yet, the Vietnam Mekong Delta produces 50% of Vietnam’s rice crop; 60% of exported fish; and 70% of the country’s fruit production (Loc et al. 2021). One of the keys to acid sulfate soil productivity is water-soil adaptive management that maintains crop-specific balance between reducing and oxidizing conditions in the plant rootzone at critical vegetative, bloom, and fruit development stages (Hanhart et al. 1997).