Page 16 - Soil Degradation, Conservation and Remediation

Chapter 1
Soil Resources and Soil Degradation

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Including rocky surfaces, deserts, and ice-covered areas, there is 130,575,894 km
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land area in the globe. About 38.5 million km (29.45 % of the earth’s ice-free land
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surface) is too dry for human habitation, and about 20.2 million km (15.46 %) of
the land occurring in the cold tundra zone is not much suitable for normal agricul-
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ture. Saline and alkaline soils occur in 3,105,000 km (2.4 % of the land surface),
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and soil acidity affects 18,420,100 km (14.1 % of the total land). Only about 12 %

of the land surface is suitable for food and fiber production, 24 % is grazing land,
and about 31 % is forestland; the remaining 33 % has many constraints for most

uses. The lands are classified into eight land capability classes based on their produc-
tivity, limitations, climate, and soil conservation requirements. Class I land is the
most suitable agricultural land, and Classes VII to VIII are not suited for cultivation.

Agricultural soils are again classified into nine land quality classes based on the
integration of three soil performance classes and three soil resilience classes. Land
quality I is the prime land. Suitability of cropping and productivity gradually
decrease from Class I to Class IX. The global arable land area is estimated to be
1.351 billion hectares, and 38 % of the arable land has been degraded at variable
intensities. The principal cause of soil degradation is the land mismanagement.

GLASOD identifi ed five main causes of soil degradation, including deforestation,
overgrazing, mismanagement of agricultural land, overexploitation of vegetation,

and (bio-) industrial activities. There are five types of land/soil degradation: water
erosion, wind erosion, physical deterioration, chemical deterioration, and degradation
of biological activity. With this background, ten “laws of sustainable soil management”
have been suggested.

1.1 Soil as a Resource

Let us add a few words to Rosewell ( 1999 ). To him and to all of us, soil is one of the
world’s most valuable natural resources. It is essential to all life forms on this planet.
It provides a physical matrix, chemical environment, and biological setting for water,

K.T. Osman, Soil Degradation, Conservation and Remediation, 1
DOI 10.1007/978-94-007-7590-9_1, © Springer Science+Business Media Dordrecht 2014