Field indicators for the identification of hydromorphic soils in the region of Viçosa, Minas Gerais - BrazilLocal indicators are useful to identify environments. In the region of Viçosa, Gleysols with their typically gray color are not common, although waterlogged soils under the plant cover "taboa" (Thypha dominguensis) are found. Most of the soils with high water tables are covered by "taboa", while the gley characteristics are not pronounced, especially in soils with high iron contents. Since there was no clear relation among the height of the water table, O2 deficiency, and color, it was hypothesized that other types of indicators for reducing conditions could be found in these environments. In pursuit of local indicators, soil, water and vegetation were characterized. Soils with different degrees of drainage limitation were studied in Cajuri (area 1); Viçosa (area 2), and Coimbra (area 3). For a field evaluation of soil redox conditions, pH and pE were measured by an electronic device, adapted to a steel probe. Despite its importance for the identification of environmental indicators, soil morphology was not a precise indicator for O2 deficiency during long periods of time, the most common characteristic of waterlogged soils. Although color is a useful indicator for numerous drainage conditions of the soil, it was not efficient in this area as well. In general, the studied Gleysols presented a chroma > 2, which surpasses the criterion for gley horizons in the Brazilian Soil Classification System. Therefore, soil color was not a good indicator for drainage limitation in these areas. The presence of "taboa" was confirmed as a good indicator for drainage limitation. Pure clusters of this vegetation were found where pH and pE values are low, but vary within a wide range. A water table above 0.60 m was found to be a good indicator for the gley status of soils.
Thypha dominguensis; criteria of classification; field pH and pE; water table
