| Abstract: | The influence of soil structure on penetration resistance Penetration resistance depends strongly on the soil structure. However, because roots may either penetrate aggregates or grow around them, the value determined for the bulk soil can only be used as a first approximation. If e.g. unconfined aggregates are penetrated, the penetration resistance increases with increasing size. If however, the aggregates are confined by being embedded in gypsum then the penetration resistance is higher but is independent of aggregate size. Thus, the outer skin is stronger than the inner part of the aggregates. When single prisms are penetrated horizontally, then the penetration resistance is smaller than the resistance to vertical penetration. On the other hand, for polyhedral structure the penetration resistance is of the same order of magnitude in both directions. |
