ABSTRACT
Changes on the structure of a Palehumult under different agricultural management

Achim Ellies S.1 y Cardenio Contreras H.
 

The effect of different agricultural management on the soil structure and mechanical properties of an Andeptic Palehumult soillocated in the coastal mountains near to Temuco in Southern Chile was evaluated. Sites with extensive and intensive management under forest, grassland, crops and horticulture, were selected. During spring and summer period undisturbed soil samples were collected to study variation on soil structure properties such as bearing capacity, shear strength, pore size distribution and water conductivity, and on field soil penetration resistance was determined. The sites under extensive and peasant managements showed a strong degradation of their structural properties, which was reflected on a loss of coarse pore volume and a reduction of the water conductivity. Under intensive management, changes on the structural properties in a low grade were observed. The different management studied also showed changes on mechanical properties related to root growth. The degraded sites showed higher internal cohesion, penetration resistance and bearing capacity. The seasonal changes of mechanical properties also were greater on sites with poor structure.

Keywords: Soil structure, bearing capacity, shear strength, penetration resistance.
1 Instituto de Ingeniería Agraria y Suelos, Casilla 567, Valdivia, Chile.