Page 8 - Soil Degradation, Conservation and Remediation

Pref ace

Recently, I wrote a book entitled Soils: Principles, Properties and Management
which Springer published in December 2012. The original manuscript had a long
chapter of more than 75 normally typed pages on soil resources and degradation.
While writing the chapter, I collected more than adequate literatures on the levels

and impacts of soil degradation worldwide. I figured it would be a good idea to

extend it with necessary details, examples, tables, and figures into a full-fl edged
book on soil degradation, conservation, and remediation should an opportunity ever
present itself. I did so eventually, and while writing, I endeavored to give lucid
accounts of the principal processes of soil degradation, its effects on soil quality,
plant production and human health, and methods of improvement of degraded soils.
The decline in soil quality due to human interventions in soil, water, and environ-
ment is called human-induced soil degradation. H. Eswaran et al.’s observation on
the looming significance of soil degradation studies is noteworthy: “Soil degrada-

tion has been a major global issue during the 20th century and will remain high on
the international agenda in the 21st century. The importance of soil degradation
among global issues is enhanced because of its impact on world food security
and quality of the environment” ( http://soils.usda.gov/use/worldsoils/papers/land-
degradation- overview.html ). Deforestation of fragile lands, overexploitation of

vegetation and biomass resources, shifting cultivation, overgrazing, unbalanced
fertilizer use, non-adoption of soil conservation management practices, use of
ground water in excess of the capacity for recharge, inappropriate irrigation system,
and indiscriminate disposal of wastes are some of the factors responsible for soil
degradation. Physical deterioration of soil including surface sealing, hardsetting and
compaction, water and wind erosion, and chemical soil degradation including nutri-

ent depletion, acidification, salinization, and soil pollution are the chief processes of
soil degradation. Decline in soil productivity and fall in crop quality are the measur-
able impacts of soil degradation. The productivity of some lands has declined by as

much as 50 % due to soil erosion and desertification. Mean yield reduction due to
erosion in Africa is 8.2 %. Annual loss in productivity due to water erosion is esti-
mated at 36 million tons of cereal equivalent to US$5,400 million and due to wind
erosion to US$1,800 million in South Asia. It is estimated that the total annual cost

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