Mangroves are coastal ecosystems, ecotones between the continent and the sea, characteristic of tropical and subtropical regions, subject to tidal regime. They have unique physicochemical and metabolic properties with high primary productivity, functioning as an ecological reserve, nursery and nutrient medium. Therefore, they constitute a filter, serving as an ultra-sensitive "thermometer" to the biogeochemical and sedimentological variations of the environment. The present work proposes the generation of data on the macronutrient content (Ca, Mg, Na, S) of soils from this ecosystem, subsidizing ecological studies between the plant-soil relationship and helping in the planning of use, preservation, and conservation. The soil samples were collected at three sites along the bay of Mojuim, municipality of São Caetano de Odivelas/PA. These sites were drilled with a mud auger to a depth of 3 m, always in the last of three contiguous plots of 20x20m each, used for biological inventory. These samples were analyzed according to the usual analytical methods described in EMBRAPA (1997). In the A and Cg textural horizons, the clay fraction predominated in relation to the other soil mineral fractions (silt and sand), varying in the following order: clay> silt>fine sand. The results obtained reveal a soil rich in macronutrients, whose values will be compared with other mangroves of the northern Brazilian coast.
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