The development of soil structure is one of the end products of the
natural soil-forming process. Aggregation of sand, silt and clay particles
increases the soil bulk volume (decreases bulk density) and creates large pore
spaces between the particles and between aggregates. This has favorable
effects on aeration, water permeability and root penetration. One of the most
important functions of wise agricultural land husbandry is the maintenance of
good structure or tilth.
Most conditions present in the urban situation tend to destroy structure
and prevent its formation. (Craul and Klein, 1980; Patterson, 1976). These
conditions include:
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