In many land use systems worldwide soil deformation is a major problem arising from increasing land use intensity. Altered soil functions, in particular reduced hydraulic conductivities and impeded aeration, influence the top soil layers. This has an important effect on vulnerability to erosion, in particular.
Assessing very thin soil layers like soil crusts requires very sensitive and highly accurate equipment which should also allow very small vertical stress application during measurement. Many different shear test devices are available for measuring shear strength, including direct shear apparatus, shear vanes or cone penetrometers, but the construction of the frame shear test requires a thickness of the sample of at least 3 cm for example, which excludes such a test device for soil crust strength determination.
Soil stability is a decisive factor for erosion risk reduction. Soil stability is determined by shear resistance or the angle of internal friction, depending on or varying through soil-water pressure and humus content. Soil shear resistance will increase with increasing organic carbon content. Air-dry soil state samples will result in the smallest resistance to shearing in comparison with the range of water content applied. The effect of bulk density on soil shear strength depends on the water content and is distinct for a higher range of vertical loads.
Product code: 08.65
The air permeameter apparatus measures the permeability or conductance of an (undisturbed) soil...More information
Product code: 08.67
In many land use systems all over the world soil deformation is a major problem due to...More information
Product code: 08.68
The shear test apparatus (art. no. 08.68) measures the shear stress of an undisturbed soil...More information