Agriculture Reference
In-Depth Information
management involves the manipulation of physical, chemical, and biological proper-
ties, such that soil processes underpinning ESs are sustained and risks of degrada-
tion of soil quality (SQ) are minimized. The goal of soil management is to optimize
and sustain the positives and minimize the risks of negatives (e.g., erosion, saliniza-
tion, compaction). Thus, the objective of this chapter is to describe the rationale for
science-based management of soils and outline the basis of priorities for research,
development, and outreach, and the need to enhance awareness about the importance
of sustainable management of the world's soil resources.
19.2 PROCESSES, FACTORS, AND CAUSES
OF SOIL DEGRADATION
Processes refer to mechanisms or biological, physical, chemical, ecological, and
geological reactions and transformations underpinning changes in SQ, ecosystem
functions, and services. Principal soil degradation processes include decline in soil
structure, crusting, compaction, erosion, depletion of nutrients and soil organic car-
bon (SOC), salinization, acidification, elemental imbalance, pollution and contami-
nation, anaerobiosis, and drought or the hydrologic imbalance (Figure 19.1). Factors
Processes
Organic carbon and nutrients
Decline of soil structure
Erosion
Salinization
Depletion of soil
Acidification
Compaction
Crusting
Anaerobiosis
Pollution
Contamination
Drought
Factors
Parent material
Te rrain and slope climate
and climate change
Climax vegetation
Drainage
Landscape position
Soil type
Soil
degradation
Causes
Land use
Land use change
Farming systems
Cropping sequences
Farm size and income
Land tenure
Institutional support
Social equity
Infrastructure
Education
Civil strife
Political stability
Political will
FIGURE 19.1
Interactive effects of processes, factors, and causes of soil degradation.
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