Wetland Soils from Lake Patzcuaro, Michoacan, Mexico

In Mexico and particularly in the state of Michoacan, the genesis, morphology and function of hydromorphic soils has not been sufficiently studied, despite having large areas of continental wetlands such as the vadose region of Lake Patzcuaro. We studied two wetlands representative of the shore of Lake Patzcuaro, Michoacan. One was permanently saturated with Gleysols development and the other was had periodic flooding and fluvisols development in a large floodplain. The results indicate the presence of haplic gleysol (colluvic, eutric) (WEB, 2006), dark brown in color, with moderate amounts of organic carbon (0.87 % average), clay> 30 %, predominant structure of subangular polyhedra and prisms with segregation of sesquioxides ferromanganese protruding from hypo-coatings of iron oxides, and the presence of traces of ostracods throughout most of the profile. Lithological discontinuity is prominent. The alluvial wetlands contain haplic fluvisol (hyperhumic, eutric) (WEB, 2006) with soil having a grayish brown matrix, a high content of organic matter throughout the profile (> 7 %), and traces of ostracods. These soils have a high base saturation (> 50 %). Three wet zones are well defined within the soil: a lower permanent endosaturation zone, an intermediate zone resulting from capillarity and an alternating wetting-drying zone in the epipedons.