Influencia del contenido en materia orgánica sobre las propiedades físicas del sueño

Abstract

[Abstract] Soil physical characteristics of agricultural soils with a range of texture and organic matter content, i. e., dry and wet pore space organisation, were investigated. In order to study the specific effect of organic matter for each soil, frequently both grassland and cultivated adjacent land were sampled. Because of the complexity of the soil particle structure, measurements were performed at the textural level on 2-3 mm aggregates. The compactness of grassland horizons was found to be lower than that of its cultivated counterparts. Mercury intrusion porosimetry showed that lacunar pores prevailed, whose volume increased as organic carbon content increased. The volume of clay-fabric pores was very small and did not appear to depend on the variation in organic matter content. Water content near saturation increased with increasing organic matter content and for potentials of about 1,500 kPa water retention curves tended to converge. Pore size distribution patterns as measured mercury intrusion porosimetry and derivedfrom water retention characteristics were compared. The low shrinkage potential of moderately coarse and medium textured soils was also verified. A lack of potential for regeneration of good soil structure by fragmentation was deduced from the shrinkage curves.