Propiedades micromorfológicas del suelo superficial y subsuperficial en un ambiente pedemontano árido de patagonia, Argentina

BOUZA, PJ; DEL VALLE, HF

Ciencia Del Suelo

Asociación Argentina de la Ciencia del Suelo

Lugar: Buenos Aires; Año: 1998 vol. 16 p. 30 - 38

0326-3169

The objectives of this paper were: 1) to establish a classification system of crusts and layers, based on micromorphology and genesis, and 2) to determine the pedological modifications in the presence of the progressive soil degradation processes. The study site is located in a shrubby steppe of northeastern Chubut. The microtopographical pattern are represented by mounds beneath shrub clumps and areas of desert pavements. Taking into account to morphological properties, the surface layers were classified in four superficial soil condition classes. The classes represent a degradational sequence from better edaphic conditions (class 1) to desert pavement development (class 4). In these microsites, three morphological types of surface crusts and layers were identified, including a) single grain layers (class 1), b) run off sedimentational crusts (class 2) and 3) structural vesicular crusts (classes 3 and 4). Moreover the Bt and Btk horizons were studied. On the upper boundary, these horizons presents physical degradation and hydric erosion evidences and should relate to past wetter climates under which the soil formed. The decrease of the iluviation process are evidenced by: 1) discontinuous clay coating on voids walls, and 2) fragmented clay coating in the micromass with crystallitic b-fabric due to micrite intergrowths. The physical degradation was evidence by dominate vughy microstructure created by disconnection of packing pores due to settling and compaction.