ABSTRACT
The term soil crusting refers to the forming processes and the consequences of a thin layer at the soil surface with reduced porosity and high penetration resistance. Surface crusts are largely blamed for initiating runoff, favoring interrill soil erosion and inhibiting seedling emergence. This chapter summarizes various aspects of soil crusting with a peculiar focus on the methods for assessment of this type of soil degradation. In addition to morphological changes, soil crusting is associated with a dramatic reduction in the saturated hydraulic conductivity of soil surface which can be used as a sealing index. A wide variety of tests based on soil structural instability have been developed to predict soil susceptibility to crusting. Some soil engineering properties have been tested also as predictors of susceptibility to crusting, in particular the Atterberg liquid limit.
