Soil degradation is one of the world’s great environmental problems. At the same time as rivers are contaminated with sediments eroded from soils, severe erosion in many parts of the world results in a significant decrease in soil productivity. Although the immediate cause for water erosion may be intense rainfall, there are a number of reasons soil loss is especially severe in some situations. Susceptibility to erosion is influenced by soil type (silts are more susceptible), degree of aggregate stability, and extent of soil cover by residue and/or growing plants. Compaction, another form of soil degradation, can go unnoticed unless one looks for the symptoms, but it can have a damaging effect on plant growth. For a discussion of tried and true ways of reducing erosion and compaction, see chapters 14 and 15. And for how to reclaim saline, sodic, and saline-sodic soils, see chapter 20.
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