Submicroscopy of Aggregates of Luvic Phaeozems under Different Land Uses in the Southeast of the Buenos Aires Province, Argentina

Resumo

Soil aggregates are key elements of soil structure that play an important role in several soil processes. One of the major factors that affect soil structure are the anthropogenic activities. Such modifications can be studied by different scales of analysis, macro, meso and microscale; and measured through different soil properties. The aim of our work is to perform description at submicroscopic scale of the soil aggregates matrices of Luvic Phaeozems affected by the different uses in the southeastern part of Buenos Aires, Argentina. The descriptions were made taking into account: (a) characteristics of aggregates matrix, (b) elemental composition of matrix and (c) organics components (plant residues, other carbon components) and microbiogical components. In natural and forested soils, the content of organic carbon in the aggregate matrices is higher, while in cultivated soils there is a decrease, which results in a decrease in their structural stability. The observations under MEB and the EDAXs have contributed to defining the morphological characteristics of the aggregate matrices from granular porous organic ones in non-tilled soils to compact ones in cultivated plots.