ABSTRACT
Degradation of the soil can be considered as an alteration of its physical, chemical and biological properties which from an agricultural point of view results in a reduction or loss of productivity. Physical soil degradation is mainly a result of soil structure breakdown when soil aggregates are deformed by a force applied either externally from the impact of rain, or internally from the breaking out of trapped air when aggregates are flooded. A deterioration of soil structure stability may be observed as a splitting off of the individual soil particles from aggregates. Soil strength due to biological activity is also reduced because increasing tillage intensity reduces e.g., earth worm abundance, number of earth worm channels, net consumption of organic matter, etc. The proctor test is recommended as a standard test mainly for homogenized soil material in order to define the effect of water content and of the organic and mineral composition of soils on soil compactability.
