To minimize the environmental impact of sea salt production and promote agricultural sustainability, studies on the reuse of marine gypsum have piqued interest in semi-arid regions. This study aimed to (a) verify the characteristics of marine gypsum, (b) analyze its agronomic potential for replacing agricultural gypsum as a nutrient source in acidic sandy soils, and (c) assess its effectiveness in recreating sodic soils. The study comprised two experiments: acidic sandy soil (Red Latosol) and sodic clayey soil (Fluvic Neosol). Both experiments employed a completely randomized design with 14 treatments and three replications. The treatments included as follows: (1) soil without any additional treatment (Control-C)
(2) agricultural gypsum (AG) (40 mesh-0.42 mm)-reference treatment
(3) 12 treatments involving marine gypsum (MG), with variations in recommended doses (50%, 100%, and 200%) and particle sizes (1.19, 0.84, 0.59, and 0.42 mm, corresponding to 16, 20, 30, and 40 mesh, respectively). MG exhibited higher levels of Ca