Although compaction is regarded as the most
serious environmental problem caused by conventional
agriculture (McGarry, 2001), it is the most
difficult type of degradation to locate and rationalize,
principally as it may show no evident marks on the soil
surface (Fig. 1). Unlike erosion and salting that give
strong surface evidence of the presence of land
degradation, degradation of soil structure requires
physical monitoring and examination before it is
uncovered and its extent, nature and cause resolved.
The hidden nature of soil structural degradation (SSD)
leads to specific problems such as poor crop growth or
water infiltration that may be blamed on other causes.
In addition, SSD is often blamed for poor crop
performance when it is actually not present. Farmers
rarely link their land management practices to the
causes of SSD and remain unaware that many deepripping
exercises worsen SSD (McGarry and Sharp,
2001). Because subsoil compaction is very persistent
and possibilities of natural or artificial loosening have
been disappointing, it has been acknowledged by the
European Union (EU) as a serious form of soil
degradation (Akker and Canarache, 2001).